ASTM-D6007-02 甲醛检测方法
Designation:D6007–02
Standard Test Method for
Determining Formaldehyde Concentration in Air from Wood Products Using a Small Scale Chamber1
This standard is issued under the?xed designation D6007;the number immediately following the designation indicates the year of original adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.A superscript epsilon(e)indicates an editorial change since the last revision or reapproval.
1.Scope
1.1This test method measures the formaldehyde concentra-tions in air from wood products under de?ned test conditions of temperature and relative humidity.Results obtained from this small-scale chamber test method are intended to be comparable to results obtained testing larger product samples by the large chamber test method for wood products,Test Method E1333. The results may be correlated to values obtained from Test Method E1333.The quantity of formaldehyde in an air sample from the small chamber is determined by a modi?cation of the National Institute for Occupational Safety and Health(NIOSH) 3500chromotropic acid test procedure.Other analytical pro-cedures may be used to determine the quantity of formaldehyde in the air sample provided that such methods give results comparable to those obtained by using the chromotropic acid procedure.However,the test results and test report must be properly quali?ed and the analytical procedure employed must be accurately described.
1.2The wood-based panel products to be tested by this test method are characteristically used for different applications and are tested at different relative amounts or loading ratios to re?ect different applications.This is a test method that speci?es testing at various loading ratios for different product types. However,the test results and test report must be properly quali?ed and must specify the make-up air?ow,sample surface area,and chamber volume.
1.3Ideal candidates for small-scale chamber testing are products relatively homogeneous in their formaldehyde release characteristics.Still,product inhomogeneities must be consid-ered when selecting and preparing samples for small-scale chamber testing.
1.4The values stated in SI units are the standard values. Any values given in parentheses are for information only. 1.5This standard does not purport to address all of the safety concerns,if any,associated with its use.It is the responsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.
2.Referenced Documents
2.1ASTM Standards:
D3195Practice for Rotameter Calibration2
D5197Test Method for Determination of Formaldehyde and Other Carbonyl Compounds in Air(Active Sampler Methodology)2
D5221Test Method for Continuous Measurement of Form-aldehyde in Air2
E77Test Methods for Inspection and Veri?cation of Ther-mometers3
E220Method for Calibration of Thermocouples by Com-parison Techniques3
E337Test Method for Measuring Humidity with a Psy-chrometer(the Measurement of Wet-Bulb and Dry-Bulb Temperatures)2
E691Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method4
E741Test Method for Determining Air Change in a Single Zone by Means of Tracer Gas Dilution5
E1333Test Method for Determining Formaldehyde Con-centrations in Air and Emission Rates from Wood Products Under De?ned Test Conditions Using a Large Chamber6 2.2U.S.Department of Housing and Urban Development (HUD)Standards:
24CFR3280,Manufactured Home Construction and Safety Standards7
2.3NIOSH Standard:
3500Formaldehyde Method8
2.4Other Documents:
Minnesota Statutes Section144.495,325f.18,and325F.181 Formaldehyde Gases in Building Materials9
1This test method is under the jurisdiction of ASTM Committee D07on Wood and is the direct responsibility of Subcommittee D07.03on Panel Products.
Current edition approved April10,2002.Published June2002.Originally published as https://www.wendangku.net/doc/027144315.html,st previous edition D6007-96.
2Annual Book of ASTM Standards,V ol11.03.
3Annual Book of ASTM Standards,V ol14.03.
4Annual Book of ASTM Standards,V ol14.02.
5Annual Book of ASTM Standards,V ol04.11.
6Annual Book of ASTM Standards,V ol04.10.
7Federal Register,V ol49,No.155,Aug.8,1984,available from Superintendent of Documents,https://www.wendangku.net/doc/027144315.html,ernment Printing Office,732N.Capitol St.,NW,Mail Stop: SDE,Washington,DC20401.
8U.S.Dept.of Health and Human Services,1989,available from Superintendent of Documents,https://www.wendangku.net/doc/027144315.html,ernment Printing Office,732N.Capitol St.,NW,Mail Stop: SDE,Washington,DC20401.
9Available from Print Communications,Dept.of Administration,117University Ave.,St.Paul,MN55155.
1
Copyright?ASTM International,100Barr Harbor Drive,PO Box C700,West Conshohocken,PA19428-2959,United States.
3.Terminology
3.1De?nitions of Terms Speci?c to This Standard:
3.1.1air change rate,N(N is equal to Q/V)—the ratio of conditioned and?ltered air that enters or is replaced in the small chamber in one hour divided by the interior volume of the small chamber,air changes per hour(ACH).
3.1.2equilibrium concentration,C eq—is that C s measured when Q equals zero,ppm.
3.1.3loading ratio,L—(L is equal to A/V)the total exposed surface area,excluding panel edges,of the product being tested divided by the test chamber’s interior volume,m2/m3.
3.1.4make-up air?ow,Q—the quantity of conditioned and ?ltered air fed into the chamber per unit time,m3/h.
3.1.5mass transfer coeff?cient,K—a measure of the perme-ability of the emitting surface of a wood based panel product, m/h.K is calculated as follows:10
K5~Q/A!~C s!
~C eq2C s!(1)
3.1.6N/L ratio—(N/L is equivalent to Q/A)the ratio of air ?ow through the chamber to sample surface area,m/h,as follows:
N/L5Q/V
A/V
5~Q/V!3~V/A!5Q/A(2)
3.1.7Q/A ratio—the ratio of air?ow through the chamber (Q)to sample surface area(A),m/h.
3.1.8sample surface area,A—the total area of all sample faces exposed in the chamber,m2.
3.1.9steady state concentration,C s—the interval when the formaldehyde concentration is not changing with time(ex-pressed in parts of formaldehyde per million parts air(ppm)) under the de?ned environmental test parameters.
3.1.10volume of closed system,V—the interior volume of the test chamber,m3.
4.Signi?cance and Use
4.1Limitations on formaldehyde levels have been estab-lished for wood panel building products made with urea-formaldehyde adhesives and permanently installed in homes or used as components in kitchen cabinets and similar industrial products.This test method is intended for use in conjunction with the test method referenced by HUD Rules and Regula-tions24CFR3280for manufactured housing and by Minne-sota Statutes Section144.495for housing units and building materials.This test method provides a means of testing smaller samples and reduces the time required for testing.
4.2Formaldehyde concentration levels obtained by this small-scale method may differ from expected in full-scale indoor environments.Variations in product loading,tempera-ture,relative humidity,and air exchange will affect formalde-hyde emission rates and thus likely indoor air formaldehyde concentrations.
4.3This test method requires the use of a chamber of0.02 to1m3in volume to evaluate the formaldehyde concentration in air using the following controlled conditions:
4.3.1Conditioning of specimens prior to testing,
4.3.2Exposed surface area of the specimens in the test chamber,
4.3.3Test chamber temperature and relative humidity,
4.3.4The Q/A ratio,and
4.3.5Air circulation within the chamber.
5.Interferences
5.1The NIOSH3500analytical method lists phenols as a negative interference when present at an8:1excess over formaldehyde.Modi?cations in the analytical procedure shall be made when relatively high phenol to formaldehyde concen-trations(8:1)are anticipated.11,12
6.Apparatus
6.1Test Chamber—The interior volume of the small cham-ber shall be from0.02to1m3.The interior of the test chamber shall be free of refrigeration coils that condense water and items such as humidi?ers with water reservoirs since water has the potential for collecting formaldehyde and thus in?uencing test results.The interior surfaces of the small chamber, including any sample support system,shall be a nonadsorbent material.Stainless steel,aluminum,and polytetra?uoroethyl-ene(PTFE)have been found appropriate as chamber lining materials.All joints except for doors used for loading and unloading specimens should be sealed.Doors shall be self-sealing.
6.2Make-Up Air:
6.2.1The make-up air shall come from a?ltered dust-free environment and contain not more than0.02ppm of formal-dehyde.This can be accomplished by passing make-up air through a?lter bed of activated carbon,activated alumina impregnated with potassium permanganate,or other materials capable of absorbing,or oxidizing formaldehyde.
6.2.2Make-up air for the chamber must pass through a calibrated air?ow measuring device.
6.2.3Air Circulation—Low speed mixing fans or multi-port inlet and outlet diffusers are two techniques that have been used successfully to ensure mixing of the chamber air over all sample surfaces.
6.2.4Air Sampling Port—The exhaust?ow(that is,cham-ber outlet)is normally used as the sampling point,although separate sampling ports in the chamber can be used.The sampling system shall be constructed of a material to minimize adsorption(for example,glass,stainless steel),and the system should be maintained at the same temperature as the test chambers.
6.3Examples of acceptable reagents,materials,and equip-ment are provided in Appendix X1.
10Christensen,R.L.,and Anderson,W.H.,Measuring Formaldehyde Concen-trations Using a Small Scale Chamber,Proceedings23rd International Particleboard/Composite Materials Symposium,W.S.U.,1989.
11Hakes,D.,Johnson,G.,and Marhevka,J.,Procedure for Elimination of Phenol Interference in the Chromotropic Acid Method for Formaldehyde,American Industrial Hygiene Association,April1984.
12Technical Bulletin No.415,National Council of the Paper Industry for Air and Stream Improvement Inc.(NCASI),
1983.
7.Hazards
7.1Chromotropic Acid Reagent Treatment —(See 10.3.4and 10.3.5.)During this hazardous operation,the operator must wear rubber gloves,apron,and a full face mask or be protected from splashing by a transparent shield such as a hood window.The solution becomes extremely hot during addition of sulfuric acid.If acid is not added slowly,some loss of sample could occur due to splattering.
7.2Cleaning Chemicals for Glassware —Use appropriate precautions if cleaning chemicals are considered to be hazard-ous.
8.Test Specimens
8.1Standard Face and Back Con?guration —Loading (L or A/V )is de?ned as the total exposed specimen surface area,excluding edge area,divided by the chamber volume.Alumi-num tape shall be used to cover the edges of the specimens if the edge exposure is greater than 5%of the surface area,thereby retarding formaldehyde emission from the edge.The Q/A ratios in Table 1are used for testing wood panel products containing formaldehyde.Each small chamber will have a unique value for the make-up air ?ow (Q )dependent on the sample surface area used,and the type of product tested.8.2Nonstandard Sample Con?guration Testing Products with Single Surface Exposed —Some products have signi?-cantly different formaldehyde release characteristics for each surface.In those cases,panels may be tested back-to-back with edges taped together.The panels shall be identi?ed as tested in the back-to-back mode.
8.3Combination Testing —Different products may be tested in combination.Qualify the test report and note the Q/A ratio used.
9.Sample Material Handling and Specimen Conditioning 9.1Handling —Materials selected for testing shall be wrapped in polyethylene plastic having a minimum thickness of 0.15mm (6mil)until sample conditioning is initiated.When testing wood products that are not newly manufactured such as after original application,installation or use,the method of packaging and shipping the products for testing shall be fully https://www.wendangku.net/doc/027144315.html,rmation on the age and history of the product shall be detailed in the test report.
9.2Conditioning —Condition test specimens with a mini-mum distance of 0.15m (6in.)between each specimen for 2h 615min at conditions of 2463°C (7565°F)and 5065%relative humidity.The formaldehyde concentration in the air within 0.3m (12in.)of where panels are conditioned shall be not more than 0.1ppm during the conditioning period.Alter-native conditioning intervals may give better correlation,such as seven day conditioning that parallels Test Method E 1333.10.Procedure
10.1Test Procedure for Materials :
10.1.1Purge the chamber by running empty or with the use of ?lters designed to reduce the formaldehyde background concentration in air,or both.The formaldehyde background concentration in air of the empty operating chamber shall not exceed 0.02ppm.Clean chamber surfaces with water or suitable solvent if formaldehyde background concentrations approach 0.02ppm.
10.1.2Locate the specimens in the chamber so that the conditioned air stream circulates over all panel surfaces.
10.1.3Operate the chamber at 2561°C (7762°F)and 5064%relative humidity.Record the temperature,relative humidity,and barometric pressure during the testing period.Conduct the chamber test at a given Q/A ratio and record this ratio in the report.
10.1.4Specimens remain in the operating chamber until a steady state formaldehyde concentration is reached.The time may be estimated using the following equation:
t 5
21n ~12C t /C s !V
Q 1KA
(3)
where:t =time to any percent of C s less than 100%(such as
99.9999999999,and so forth),C t
=concentration at time,t ,C s =steady state formaldehyde concentration,A =product surface area,m 2,V =chamber volume,m 3,K =mass transfer coefficient,m/h,and ?1n =negative natural log.
It is necessary to know the range of K for the product involved.If K is unknown,a conservative estimate based on the literature may be used.10Alternatively,back to back air tests giving replicate values within the error of the analytical method may be used.
10.2Air Sampling —Purge air sampling lines for
1min.At the sampling station,bubble air through a single impinger containing 20mL of a 1%sodium bisul?te (NaHSO 3)solu-tion.A ?lter trap may be placed between the impinger and the ?owmeter.Set a calibrated ?owmeter to maintain an average air?ow of 160.05L/min for 30min with time measured accurately to within 5s.Following air sampling,analyze the collection solution.
10.3Analysis of Air Samples :
10.3.1Pipet 4mL of the NaHSO 3solution from the im-pinger into each of three 16by 150-mm screwcap test tubes for triplicate analysis of each impinger sample.
10.3.2Pipet 4mL of 1%NaHSO 3into a 16by 150-mm screwcap test tube to act as a reagent blank.
10.3.3Add 0.1mL of 1%chromotropic acid reagent to each test tube.Shake tube after addition.
10.3.4Slowly and carefully pipet 6.0mL concentrated sulfuric acid (H 2SO 4)into each test tube (Warning —See 7.1.)and allow to ?ow down the side of test tube.Allow the volumetric pipet to drain.Do not blow out .Before placing caps
TABLE 1Q/A Ratios,62%
Test Method E 1333L (m 2/m 3)
N/L or Q/A (m/h)
Product Type
0.950.526hardwood plywood wall paneling 0.43
1.173
particleboard ?ooring panels,industrial particleboard panels,
industrial hardwood plywood panels 0.26 1.905medium density ?berboard (MDF)0.13 3.846
particleboard door core
on test tubes,check the condition of the polytetra?uoroethyl-ene (PTFE)cap liners to make sure they are clean and not deteriorated.
10.3.5Slowly and gently agitate test tubes to
affect mixing.Mixing is complete when there is no sign of strati?cation.Caution needs to be taken due to the exothermic chemical reaction.Rapid mixing will cause heating and a pressure increase which may break the test tube.Vent test tubes to release pressure.
10.3.6If absorbance readings exceed 1.0or if spectropho-tometric analysis is performed within 2h,heat capped test tubes to 95°C or place capped test tubes in a boiling water bath for 1562min to ensure that the chemical reaction is completed.Remove tubes from water bath and allow to cool to room temperature.
10.4Absorbance Readings :
10.4.1Standardize the spectrophotometer using distilled water at 580nm in accordance with the instrument’s operating instructions.The reagent blank shall be read against distilled water because an absorbance above 0.100for the reagent blank indicates contamination of reagent blank or improper solution preparation.If absorbance for the reagent blank compared to distilled water is greater than 0.100,repeat the entire standard-ization procedure.
10.4.2Zero the instrument using the reagent blank if the absorbance is not greater than 0.100(compared to distilled water as zero).Alternatively,the instrument may be left zeroed on distilled water,and the absorbance of the reagent blank subtracted from the absorbance of the standard solutions.10.4.3Read and record absorbance at 580nm for each test tube prepared (see A4.6-A4.9).If the absorbance of the specimen solution is found to fall outside the preferred absorbance range (>1.0),steps 10.3.1-10.3.4may be repeated using an appropriate dilution of each impinger solution.11.Calculation
11.1Convert the volume of air sampled to the volume of air at standard conditions as follows:
V s 5
V 3P 32981013~T 1273!
(4)
where:
V s =volume of air at standard conditions (101kPa and
298K),L,
V =volume of air sampled,L,P =barometric pressure,kPa,and T =temperature of sample air,°C.
11.2Calculate total micrograms of formaldehyde collected in each impinger sample as follows:
C t 5C a 3F a
(5)
where:
C t =total formaldehyde in the sample,μg,
C a =total quantity of formaldehyde in the sample aliquots
taken from the impinger (as determined from the calibration curve in Annex A4),μg,and
F a =
aliquot factor 5sampling solution volume,mL aliquot used,mL
11.2.1Calculate the concentration of formaldehyde in air in the small chamber as follows:
C s 5C t 324.47V s
330.03
(6)
where:
C s
=parts of formaldehyde per million parts air,ppm,30.03=molecular weight of formaldehyde,and
24.47=μL of formaldehyde gas in 1μmol at 101kPa and
298K.
Round calculated formaldehyde concentrations to the near-est 0.01ppm.Round up to the nearest 0.01ppm any value at or in excess of 0.005ppm.Round down all values below 0.005to the nearest 0.01ppm.
11.3When the chamber temperature differs from 25by 1?4°C (77by 1?2°F)or more,adjust the formaldehyde concentra-tions obtained to a standard temperature of 25°C (77°F)using a formula developed by Berge,et al.13Annex A1contains a table of conversion factors for use at different observed test temperatures as calculated using this formula.The observed test temperature is the average temperature for the total period of 15min prior to air sampling plus the time of air sampling.11.4The small chamber formaldehyde concentration in air shall be adjusted to a concentration at 50%relative humidity when the difference in relative humidity from 50%is greater than or equal to 1%(see Annex A2).
12.Report
12.1Report the following information:12.1.1Test number.
12.1.2Title of report shall state if standard face and back con?guration testing (see 8.1)or if nonstandard con?guration testing (see 8.2)was performed.
12.1.3The manner in which materials were shipped or stored,or both:wrapped separately in vapor retarder,wrapped collectively in vapor retarder or in original box or container.If materials were shipped unwrapped,or not in the original box or container,it shall be noted in the test https://www.wendangku.net/doc/027144315.html,rmation on age and product history,if known,shall be described in the test report.
12.1.4Name of product manufacturer or name of company submitting material,or both,date of manufacture,and sam-pling date (if known).
12.1.5Description of test material or product shall include generic product name,thickness,size,if surface is ?nished or sealed (both surfaces should be described),and special treat-ment (if known).
12.1.6Specimen conditioning details to include average temperature and range (nearest 1?4°C),average relative humid-ity and range (nearest 1%),and time to the nearest minute.12.1.7Formaldehyde background concentration in the air in the area where specimens are conditioned (rounded to the nearest 0.01ppm).
12.1.8Chamber volume:nominal length,width,and height.
13
Berge,A.,Mellagaard,B.,Hanetho,P.,and Ormstad,E.B.,Formaldehyde
Release from Particleboard-Evaluation of a Mathematical Model ,Holz Als Roh-und Werkstoff 38,1980,pp.252–255.
12.1.9Chamber Q/L ratio.
12.1.10Description of specimens as loaded into chamber including number of specimens in charge and number of surfaces exposed.
12.1.11Average temperature and range(nearest1?4°C), average relative humidity and range(nearest1%),and time to the nearest minute during the sampling period.
12.1.12Chamber formaldehyde concentration in air at test conditions;chamber formaldehyde concentration in air cor-rected to25°C,50%relative humidity,rounded to nearest0.01 ppm.
12.1.13The analytical method employed if different from the NIOSH3500chromotropic acid test procedure.
12.1.14Formaldehyde background concentration of air in chamber prior to test and formaldehyde concentration of make-up air(rounded to the nearest0.01ppm).
12.1.15Air-sampling rate and length of sample time. 12.1.16Date of test.13.Precision and Bias
13.1A study including seven laboratories and four test materials was conducted in accordance with Practice E691and resulted in the following statements for precision and bias. 13.1.1Repeatability—Test results indicate a repeatability (within laboratory)precision standard deviation ranging from 0.01to0.02for products emitting0.06to0.24ppm of formaldehyde.
13.1.2Reproducibility—Test results indicate a reproducibil-ity(between laboratory)precision standard deviation ranging from0.02to0.05for products emitting0.06to0.24ppm of formaldehyde,respectively.
13.1.3Bias—No bias statement is available for this test method due to the lack of an acceptable homogeneous form-aldehyde off-gassing reference material.
14.Keywords
14.1airborne;chromotropic acid analysis;formaldehyde concentration in air;small chamber;small-scale test;wood products
ANNEXES
(Mandatory Information)
A1.TEMPERATURE CONVERSION FACTORS FOR FORMALDEHYDE
A1.1Table A1.1is based on the Berge,et al13formula to correct formaldehyde concentrations in air for temperature:
C5C o3e2R~1/t21/to!
or
C o5Ce R~1/t21/to!where:
C=test formaldehyde concentration level,
C o=corrected formaldehyde concentration level, e=natural log base,
R=coefficient of temperature(9799),
t=actual temperature,K,and
t o=corrected temperature,
K.
A2.RELATIVE HUMIDITY CONVERSION FACTORS FOR FORMALDEHYDE
A2.1Table A2.1is based on the Berge,et al 13formula to correct formaldehyde concentrations in air for relative humid-ity:
C 5C o @11A ~H 2H o !#
or
C o 5
C
11A H 2H o !
where:C =test formaldehyde concentration level,
C o =corrected formaldehyde concentration level,A =coefficient of humidity (0.0175),H =actual relative humidity,and H o =
relative humidity,%.
A3.STANDARD SOLUTIONS A AND B
A3.1Standardization of Formaldehyde Standard Solution A (1.0mg/mL):
A3.1.1Pipet 2.70mL of 37.0%formaldehyde solution into a 1L volumetric ?ask.Dilute to mark with freshly distilled water and mix well.This solution is stable for at least one month.
A3.1.2Calibrate the pH meter with standard buffer solution of pH 9.0.
A3.1.3Pipet two 50mL aliquots of formaldehyde standard Solution A into two 150-mL beakers for duplicate analysis and add 20mL of 1M sodium sul?te (Na 2SO 3)to each beaker.Sodium sul?te solution can age,thus the 1M sodium sul?te solution should be adjusted to a 9.5pH before adding to standard Solution A aliquots.
A3.1.4Place solution on magnetic stirrer.Immerse pH electrodes into the solution and carefully titrate with 0.100N hydrochloric acid (HCl)to the original pH of the solution.Record volume of HCl and corresponding pH intermittently.Make a graph of pH versus volume of HCl.
A3.1.5Calculate the concentration,C A ,of formaldehyde standard Solution A in milligrams per millilitre as follows:
C A 5
V 3N 330.03~mg per milliequivalent !
50~mL !
where:
V =0.100N HCl required at pH of 9.5from the graph
prepared in A3.1.4,mL,and
TABLE A1.1Temperature Conversion Table for Formaldehyde
N OTE 1—The Berge,et al 11equation is an exponential function.The greater the variance between actual and corrected temperature,the greater the potential error.Two horizontal lines within the table delineate the speci?ed test temperature ranges 2561°C (7762°F).
Actual To Convert to 25°C (77°F)Multiple by Actual To Convert to 25°C (77°F)Multiply by
°C (°F)°C (°F)22.2(72) 1.3625.3(77.5)0.9722.5(72.5) 1.3225.6(78)0.9422.8(73) 1.2825.8(78.5)0.9123.1(73.5) 1.2426.1(79)0.8923.3(74) 1.2026.4(79.5)0.8623.6(74.5) 1.1726.7(80)0.8323.9(75) 1.1326.9(80.5)0.8124.2(75.5) 1.1027.2(81)0.7824.4(76) 1.0627.5(81.5)0.7624.7(76.5) 1.0327.8
(82)
0.74
25.0
(77)
1.00
TABLE A2.1Relative Humidity Conversion Table for
Formaldehyde
Actual RH %
To Convert to 50%RH Multiply by
Actual RH %
To Convert to 50%RH Multiply by
46 1.08510.9847 1.06520.9748 1.04530.9549 1.0254
0.93
50
1.00
N=normality of HCl.The concentration of standard Solution A will be the average of the two analyses
conducted.
A3.2Standard Solution B:
A3.2.1Prepare formaldehyde standard Solution B by dilut-ing1mL of standard Solution A and1g of sodium bisul?te (NaHSO3)to100mL in a volumetric?ask using distilled water.This standard is stable for at least one week.
A3.2.2Calculate the concentration of formaldehyde C B in standard Solution B in micrograms per millilitre as follows:
C b5
C A3100031mL
100
A3.2.3Record the value.
A4.CALIBRATION CURVE
A4.1Prepare a1%sodium bisul?te(NaHSO3)solution by dissolving1g of NaHSO3in a100mL volumetric?ask and diluting to the mark with distilled water.This solution is stable at room temperature and should be prepared on a weekly basis.
A4.2Label six16by150mm screwcapped test tubes1,2, 3,4,5,and6.
A4.3Pipet the following volumes of1%sodium bisul?te solution and then standard Solution B(see Annex A3)into the labeled test tubes:
Tube No.Volume,mL
NaHSO3Solution B
1 4.00
2 3.90.10
3 3.70.30
4 3.50.50
5 3.30.70
6 3.0 1.00
A4.3.1Note that no Solution B was added to Test Tube1. Test Tube1will be the reagent blank.
A4.4Add0.1mL of1%chromotropic acid reagent to each test tube.Shake tube after addition.
A4.5Slowly and carefully pipet 6.0mL concentrated sulfuric acid(H2SO4)into each test tube(Warning–See7.1.) and allow to?ow down the side of the test tube.Allow the volumetric pipet to drain.Do not blow out.Before placing caps on test tubes,check the condition of the polytetra?uoroethyl-ene(PTFE)cap liners to make sure they are clean and not deteriorated.
A4.5.1Slowly and gently agitate test tubes to affect mixing. Mixing is complete when there is no sign of strati?cation. Carefully vent test tubes to release pressure.Rapid mixing will cause heating and a pressure increase with the potential for breaking the test tube.If absorbance readings exceed1.0or if spectrophotometric analysis is performed within2h,heat capped test tubes to95°C or place in a boiling water bath for 15+2min to ensure that the chemical reaction is complete. After removal,allow the test tubes to cool to room temperature. A4.6Standardize the spectrophotometer using distilled water at580nm in accordance with the instrument’s operating instructions.The reagent blank(Tube1)shall be read against distilled water.A high absorbance for the reagent indicates contamination of reagent blank or improper solution prepara-tion.If absorbance for the reagent blank compared to distilled water is greater than0.040(using a12mm cell path length),repeat the entire standardization procedure.
A4.7Zero the instrument using the reagent blank(Tube1) if the absorbance is not greater than0.040(compared to distilled water as zero).Alternatively,the instrument may be left zeroed on distilled water,and the absorbance of the reagent blank subtracted from the absorbance of the standard solutions. Recovery shall be within65%of reagent blank.
A4.8Read and record absorbance at580nm for each standard prepared(Tubes2through6).
A4.9Plot absorbance against micrograms of formaldehyde in the color developed solution.Note the amount of formalde-hyde in micrograms is based upon the concentration of formaldehyde in standard Solution B,which is dependent upon the standardization carried out on standard Solution A in Annex A3.
A4.9.1Example—If standard Solution A=100μg/mL then standard Solution B=10.00μg/mL:
Tube1=0mL Standard Solution B
310.00μg/mL=0.00μg total formaldehyde
Tube2=0.10mL Standard Solution B
310.00μg/mL=1.00μg total formaldehyde
Tube3=0.30mL Standard Solution B
310.00μg/mL=3.00μg total formaldehyde
Tube4=0.50mL Standard Solution B
310.00μg/mL=5.00μg total formaldehyde
Tube5=0.70mL Standard Solution B
310.00μg/mL=7.00μg total formaldehyde
Tube6=1.00mL Standard Solution B
310.00μg/mL=10.00μg total formaldehyde
A4.9.2The absorbance of each tube would be plotted against the total micrograms of formaldehyde in each tube. A4.9.3The absorbance of each chamber impinger aliquot specimen determined in10.4.3is compared to this calibration curve,and the total micrograms of formaldehyde in the aliquot is represented as C a in11.2.
N OTE A4.1—The calibration curve as described in this annex is provided as an example.If absorbance readings are outside of this range, dilute the solution with distilled water to a concentration that is within the calibration curve.If absorbance readings exceed1.0,place capped test tubes in a boiling water bath for1562min to ensure that the chemical reaction is completed.Vent test tubes to release pressure.Remove tubes from water bath and allow to cool to room temperature.
A4.10Preparation of the calibration curve
(A4.3-A4.9)
shall be repeated at least once more and the ?nal calibration line shall re?ect the composite of the determinations (or the curve shall be calculated using a linear least squares ?tting technique).The calibration curve may not be linear at high formaldehyde concentrations (high absorbance readings).If the plot in A4.9shows the last few points deviating from linearity,omit the points from calculations or repeat entire procedure.Further,the curve should be frequently checked based on changes in reagent lot numbers,past experience,data scatter-ing,or instrument instability.
APPENDIX
(Nonmandatory Information)
X1.REAGENTS,MATERIALS,AND EQUIPMENT FOUND SUITABLE FOR USE
X1.1Air-Sampling Apparatus
N OTE X1.1—Other apparatus and instruments may be used if equiva-lent results are anticipated.
X1.1.1Midget Impingers .14X1.1.2Rotameters ,1L/min.15
X1.1.3Line Filter ,with desiccant (to dry the air before entering rotameters).16
X1.1.4Polytetra?uoroethylene (PTFE)Tubing .16
X1.1.5Buret ,250or 500mL (to calibrate rotameters).16X1.1.6Impinger Pumps .16
X1.1.7Film-Type Laboratory Calibrators or Bubble Tube ,for calibrating pumps and rotameters.17
X1.2Analytical Apparatus
X1.2.1Spectrophotometer .18
X1.2.2Spectrochek ,16for calibration of the spectrophotom-eter.
X1.2.3Beaker ,150mL,low form.16X1.2.4Volumetric Flask ,1000mL.16X1.2.5Volumetric Flask ,100mL.16
X1.2.6Volumetric Flasks ,two,10mL.16X1.2.7Buret ,25mL,Class A.16X1.2.8pH meter .16
X1.2.9Magnetic Stirrer .16
X1.2.10Pipet ,volumetric,4mL.16
X1.2.11Pipet ,volumetric,50mL,Class A.16X1.2.12Pipet ,volumetric,6mL,Class A.16
X1.2.13Pipet ,long-tip Mohr type,2by 0.01mL.16X1.2.14Pipet,Mohr ,10by 0.1mL.16X1.2.15Safety Bulb ,for pipeting.16
X1.2.16Test Tubes ,16by 150mm,with polytetra?uoroet-hylene (PTFE)lined screw caps.16
X1.2.17For repetitive analyses of sample solutions and for added safety,use of automatic pipeting equipment may be https://www.wendangku.net/doc/027144315.html,e of the following have been found suitable.16X1.2.17.1Brinkman Dispensers ,volume 0.1to 0.5mL (for chromotropic acid),volume 1to 10mL (for sulfuric acid),and volume to 25mL (for distilled water).16X1.2.17.2Oxford Macro-Set Pipet .16
X1.2.17.3Tips ,250,for transferring 4mL aliquots.16X1.3Reagents
X1.3.1Chromotropic Acid Reagent —Dissolve 0.10g of chromotropic acid (4,5-dihydroxy-2,7-naphthalene-disulfonic acid disodium salt)in freshly distilled water and dilute to 10mL.This solution is to be made up daily.
X1.3.2Sulfuric Acid (H 2SO 4),concentrated,reagent grade.Nitrate concentration shall be less than 10ppm.X1.3.3Buffer Solution ,pH 9.0.
X1.3.4Hydrochloric Acid ,(HCl)0.100N ,standard.
X1.3.5Sodium Sul?te Solution ,1.0M —Dissolve 12.67g anhydrous sodium sul?te (Na 2SO 3)(ACS assay 99.5%)in a 100-mL volumetric ?ask and dilute to the mark with freshly distilled water.The correct amount to be dissolved should be 12.6/ACS assay of the anhydrous sodium sul?te actually being used (read assay from bottle label).
X1.3.6Formaldehyde Solution ,weight 37%.
X1.3.7Sodium Bisul?te ,(NaHSO 3),reagent grade.X1.3.8Mild Liquid Soap .
14
Ace Glass Stopper No.7531-06and 30-mL Bottle No.7531-04,available from Ace Glass Inc.,P.O.Box 688,Vineland NJ 08360,or Lurex No.191-4050,available from Lurex Scienti?c,have been found suitable for this purpose.15
Scott Specialty Gases,Model S2-315-2-4with stainless steel ?oat,available from 7425North Oak Park Ave.,Chicago,IL 60648,have been found suitable for this.16
Available from scienti?c supply houses.17
Available from SKC Inc.,334Valley View Rd.,Eighty Four,PA 15330-9614.18
Milton Roy Spectronic 20Spectrophotometer,available from scienti?c supply houses,or equivalent,has been found suitable for this
purpose.
ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this https://www.wendangku.net/doc/027144315.html,ers of this standard are expressly advised that determination of the validity of any such patent rights,and the risk of infringement of such rights,are entirely their own responsibility.
This standard is subject to revision at any time by the responsible technical committee and must be reviewed every?ve years and if not revised,either reapproved or withdrawn.Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM International Headquarters.Your comments will receive careful consideration at a meeting of the responsible technical committee,which you may attend.If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards,at the address shown below.
This standard is copyrighted by ASTM International,100Barr Harbor Drive,PO Box C700,West Conshohocken,PA19428-2959, United States.Individual reprints(single or multiple copies)of this standard may be obtained by contacting ASTM at the above address or at610-832-9585(phone),610-832-9555(fax),or service@https://www.wendangku.net/doc/027144315.html,(e-mail);or through the ASTM website (https://www.wendangku.net/doc/027144315.html,).
实验五--分光光度法测定甲醛
实验五：空气中甲醛的测定（酚试剂分光光度法） 实验目的： 掌握甲醛测定方法； 熟练掌握大气采样器和分光光度计的使用； 实验原理： 甲醛的测定方法：分光光度法、气相色谱法、酚试剂分光光度法、乙酰丙酮分光光度法； 空气中的甲醛与3-甲基2-苯并噻唑酮腙酚试剂反应生成嗪，嗪在酸性溶液中被高铁离子氧化形成蓝绿色化合物，颜色深浅与甲醛含量成正比，物质的最大吸收波长为630nm，通过比色定量。当采样体积为10L时最低检出质量浓度为0.01mg／m3。 实验仪器： 分光光度计（在630nm测定）；大气采样器；具塞比色管（10ml）；分析天平；滴定管；容量瓶；量筒；移液管等 1、吸收液原液:称量0.10g酚试剂[C6H4SN(CH3)C:NNH2·HCl,简称NBTH]，加水溶解，倾于100ml具塞量筒中，加水到刻度。放冰箱中保存，可稳定三天。吸收液：量取吸收原液5ml，加95ml水，即为吸收液。采样时，临用现配。 2、1%硫酸铁铵溶液 3、碘溶液[C（1/2I2）=0.1000mol/L] 4、1mol/L氢氧化钠溶液 5、0.5mol/L硫酸溶液：取28ml浓硫酸缓慢加入水中，冷却后，稀释至1000ml。 6、硫代硫酸钠标准溶液[C（Na2S2O3）=0.1000mol/L] 0.5%淀粉溶液：将0.5g可溶性淀粉，用少量水调成糊状后，再加入100ml沸水，并煎沸2～3min至溶液透明确。 7、甲醛标准贮备溶液：取2.8ml含量为36～38%甲醛溶液，放入1L容量瓶中，加水稀释至刻度。此溶液1ml约相当于1mg甲醛。其准确浓度用下述碘量法标定。 实验步骤： 1、样品采集：用一个内装5ml吸收液的大型气泡吸收管，以0.5L/min流量，采气10L。并记录采样点的温度和大气压力。采样后样品在室温下应在24h内分析。 2、甲醛标准贮备溶液的标定：精确量取20.00ml待标定的甲醛标准贮备溶液，置于250ml 碘量瓶中。加入20.00ml[C（1/2I2）=0.1000mol/L]碘溶液和15ml 1mol/L氢氧化钠溶液，放置15min，加入0.5mol/L硫酸溶液，再放置15min，用[C（Na2S2O3）=0.1000mol/L]硫代硫酸钠溶液滴定，至溶液呈现淡黄色时，加入1ml 5%淀粉溶液继续滴定至恰使兰色褪去为止，记录所用硫代硫酸钠溶液体积（V2），ml。同时用水作试剂空白滴定，记录空白滴定所用硫化硫酸钠标准溶液的体积（V1），ml。甲醛溶液的浓度用公式（1）计算：甲醛溶液浓度（mg/ml）=（V1-V2）×N×15/20 (1) 式中：V1――试剂空白消耗[C（Na2S2O3）=0.1000mol/L]硫代硫酸钠溶液的体积，ml； V2――甲醛标准贮备溶液消耗[C（Na2S2O3）=0.1000mol/L]硫代硫酸钠溶液的体积，ml；N――硫代硫酸钠溶液的准确当量浓度； 15――甲醛的当量； 20――所取甲醛标准贮备溶液的体积，ml。 二次平行滴定，误差应小于0.05ml，否则重新标定。 绘制标准曲线： 用1.00μg/ml甲醛标准溶液，按下表制各标准色列管
室内甲醛检测方法
室内甲醛检测方法 甲醛现在被各界普遍认为是室内第一污染，它的释放期较长，轻微超标时居住者不易察觉。超标四五倍时，居住者才能嗅出气味。找正规的检测机构做甲醛检测已成为现在入住新居的一项必不可少的程序。下面金标准小编介绍以下目前在测定甲醛常采用以下6种检测方法： 1、测定工业废气和环境空气中甲醛的乙酰丙酮分光光度法，本法使用与树脂制造、涂料、人造纤维、塑料、橡胶、染料、制药、油漆、制革等行业的排放废气以及做医药消毒、防腐、熏蒸时产生的甲醛蒸汽测定。测量范围在0.5~800mg/m3。 2、测定居住区和公共场所空气大气中甲醛浓度的AHMT(4-氨基-3-联氮-5-硫基-1，2，4-三氮杂茂)分光光度法。测量范围为0.01~0.16mg/m3。 3、适用于公共场所空气中甲醛浓度的酚试剂（MBTH）分光光度法，测量范围为0.01~0.15mg/m3。 4、气相色谱法 5、用于测定纺织品中游离甲醛含量的水萃取法。适用为游离甲醛含量为20mg/kg到3500mg/kg之间的纺织品。 6、用于测定纺织品中释放的甲醛含量的蒸气吸收法。适用为游离甲醛含量为20mg/kg 到3500mg/kg之间的纺织品。 目前，甲醛气体的检测方法按精确度划分，大致可分为两种，其一种为精密度测定法（仪器分析法），包括世界卫生组织推荐的高效液体色谱法（HPLC），气相色谱法（DNPH-GC 法）及分光光度法等；其二为简易测定法，该法主要用于快速检测，其精确度要求不高。主要有电法学方法，可以显示测定数据，以及检测管方式和测定纸方式，即通过检测气体与指示剂发生法学反应而表现出的颜色变化来测定检测气体浓度。 室内甲醛检测方法——酚试剂分光光度法 一、原理 空气中的甲醛与酚试剂反应生成嗪，嗪在酸性溶液中被高铁离子氧化成蓝绿色化合物，根据颜色深浅，比色定量。 二、仪器设备 1．气泡采样管或多孔玻板采样管； 2．QC-2A大气采样仪或TMP1500电子控时采样器；
甲醛的基本知识
甲醛的基本知识
甲醛 甲醛是一种无色，有强烈刺激型气味的气体。易溶于水、醇和醚。甲醛在常温下是气态，通常以水溶液形式出现。易溶于水和乙醇，35～40％的甲醛水溶液叫做福尔马林。甲醛分子中有醛基生缩聚反应，得到酚醛树脂(电木)。甲醛是一种重要的有机原料，主要用于塑料工业(如制酚醛树脂、脲醛塑料—电玉)、合成纤维(如合成维尼纶—聚乙烯醇缩甲醛)、皮革工业、医药、染料等。 基本信息 别称：蚁醛（formaldehyde） 产品别名：福尔马林(35～40％的甲醛水溶液) 英文名称：Formaldehyde 英文别名：Formalin; Methanal 化学式：CH2O, HCHO 结构简式：HCHO 分子量：30.03 CAS登录号：50-00-0 EINECS登录号：200-001-8
密度： 1.083 折射率： 1.3755-1.3775 闪点：60 ℃ 水溶性：soluble 沸点：-19.5 ℃ 熔点：-118 ℃ 性质 物理性质 一种无色，有强烈刺激性气味的气体。易溶于水、醇和醚。甲醛在常温下是气态，通常以水溶液形式出现。 易溶于水和乙醇，35～40％的甲醛水溶液叫做福尔马林。甲醛分子中有醛基生缩聚反应，得到酚醛树脂(电木)。 甲醛是一种重要的有机原料，主要用于塑料工业(如制酚醛树脂、脲醛塑料—电玉)、合成纤维(如合成维尼纶—聚乙烯醇缩甲醛)、皮革工业、医药、染料等。福尔马林具有杀菌和防腐能力，可浸制生物标本，其稀溶液(0.1—0. 5％)农业上可用来浸种，给种子消毒。工业上常用催化氧化法由甲醇制取甲醛。甲醛可与银氨溶液产生银镜反应[1]，使试管内壁上附着一
空气净化器对甲醛净化效率的测试方法
空气净化器对甲醛净化效率的测试方法 集团企业公司编码：（LL3698-KKI1269-TM2483-LUI12689-ITT289-
空气净化器对甲醛净化效率的测试方法 国家空调设备质量监督检验中心王宏恩邓高峰唐冬芬王智超 摘要本文分析了室内甲醛的主要来源，介绍了常用的甲醛净化处理技术。为了评 价目前市场上的净化器对甲醛的净化效果，提出了环境舱检测方法，分析对比了 几种常用的甲醛检测技术，得出了检测甲醛时合理的组合方法。 关键词空气净化器甲醛净化效率测试方法 1室内甲醛的主要来源 随着室内装修的日益普及和密闭程度的增加，室内空气污染越来越严重，甲 醛(HCHO)是主要污染物之一。据统计，装修后1～6个月内，甲醛超标率居室内达 80%，会议室和办公室内接近100%；装修3年后，超标率仍可能达50%以上[1]，这 直接影响到人们的身体健康，世界各国对此都非常关注。在2004年的“致癌公 报”上，国际癌症研究中心(IARC)公布甲醛能引起鼻腔癌和鼻窦癌，并将甲醛列 为致癌物。长期接触低剂量甲醛可引起慢性呼吸道疾病、鼻咽癌、结肠癌、脑 瘤、月经紊乱、妊娠综合症、新生儿染色体异常、白血病、青少年记忆力和智力 下降，同时还会造成细胞核的基因突变、DNA单链内交连和DNA与蛋白质交连及抑 制DNA损伤的修复等严重后果。 自然界中的甲醛是甲烷循环中的一个中间产物，背景值很低，仅有几个 μg/m3的水平。城市空气中甲醛的年平均浓度大约是0.005～0.01mg/m3，一般不超 过0.03mg/m3。而新建楼房室内的污染水平波动于0.1mg/m3上下(WHO推荐的室内指 导限值)[2]。室内甲醛主要来源于以脲醛树脂为粘合剂的各种胶合板、刨花板、中
甲醛检测方法
甲 醛 方法 AHMT 分光光度法 测定范围 本方法测定范围为2ml 样品溶液中含有0.2～3.2ug 甲醛，若采样流量为1L/min ，采样体积为20L ，则测定浓度范围为0.01～0.16mg/m3 试剂和材料 本法除注明外，均为分析纯；所用水均为无有机物水 吸收液：称取1g 三乙醇胺、0.25g 偏重亚硫酸钠和0.25g 乙二胺四乙酸二钠溶液溶于水中并稀释至1000ml 。 0.5%4-氨基-3联氨-5巯基-1，2，3-叁氮杂茂（简称AHMT ）溶液：称取0.2gAHMT 溶于0.5mol/L 盐酸中，并稀释至50ml ，此试剂置于棕色瓶中，可保存半年 5mol/L 氢氧化钾溶液：称取28.0g 氢氧化钾溶于100ml 水中。 1.5%高碘酸钾溶液：称取1.5g 高碘酸钾溶于0.2mol/L 氢氧化钾溶液中，并稀释至100ml ，于水浴上加热溶解，备用。 0.1000mol/L 碘溶液：称量40g 碘化钾，溶于25ml 水中，加入12.7g 碘。待完全溶解后，用水定容至1000ml ，移入棕色瓶中，暗处贮存。 1mol/L 氢氧化钠溶液：称量40g 氢氧化钠溶于水中，并稀释至1000ml 。 0.5mol/L 硫酸溶液：取28ml 浓硫酸缓慢加入水中，冷却后稀释至1000ml 。 硫代硫酸钠标准溶液2 2 3 0.1000/N a S O c m ol L =:可购买标准试剂配制。 0.5%淀粉溶液：将0.5g 可溶性淀粉用少量的水调成糊状后，再加入10ml 废水，并煮沸2～3min 至溶液透明，冷却后，加入0.1g 水杨酸或0.4g 氯化锌保存。 甲醛标准贮备溶液：取2.8ml 甲醛溶液（含甲醛36%～38%）于1L 容量瓶中，加入0.5ml 硫酸并用水稀释至刻度线，摇匀。其准确浓度用下述碘量法标定。 甲醛标准贮备溶液的标定：精确量取20.00ml 甲醛标准贮备溶液，置于250ml 碘量瓶中。加入20.00ml0.0500mol/L 碘溶液和15ml1mol/L 氢氧化钠溶液，放置15min 。加入20ml0.5/L 硫酸溶液，再放置15min ，用0.1000mol/L 硫代硫酸钠溶液标定，至溶液呈淡黄色时加入1ml0.5%淀粉溶液，继续滴定至刚使蓝色消失为终点，记录所用硫代硫酸钠溶液体积，同时用水作空白滴定。
甲醛的基本知识及危害
甲醛的基本知识及危害-CAL-FENGHAI-(2020YEAR-YICAI)_JINGBIAN
甲醛的基本知识及危害 甲醛分子的球棍模型 甲醛是一种无色，有强烈刺激型气味的气体。易溶于水、醇和醚。甲醛在常温下是气态，通常以水溶液形式出现。易溶于水和乙醇，35～40%的甲醛水溶液叫做福尔马林。据研究和使用证明：据研究和使用证明：晶体石膏灯有一种天然的负离子散播功能，可以有效清除室内甲醛等有害气体，净化室内空气。中科院经实验证实：小粒径负离子清除甲醛的有效率达%以上，长期使用达99%。 中文名称：甲醛 中文别名：福尔马林、甲醛水、蚁醛溶液 英文别名：Formalin，Formol ，Methanal solution ，Oxymethylene solution ，Methyl aldehyde solution 化学式：HCHO 分子空间构型：平面型 相对分子质量： CAS：50-00-0 EINECS号： 200-001-8
InChI： InChI=1/CH2O/c1-2/h1H2 性状 无色水溶液或气体。有刺激性气味。液体在较冷时久贮易混浊，在低温时则形成三聚甲醛沉淀。蒸发时有一部分甲醛逸出，但多数变成三聚甲醛。本品为强还原剂，在微量碱性时还原性更强。在空气中能缓慢氧化成甲酸。能与水、乙醇、丙酮任意混溶。 pH ～。相对密度(d2525)～。熔点-118℃，沸点℃。折光率(n20D)。闪点60℃。易燃。低毒，半数致死量(大鼠，经口)800mG/kG。其蒸气能强烈刺激粘膜。 储存 水溶液密封避光在16℃以上的温处保存，低温处不宜久贮。 用途 分析测定铵盐和氨基酸。显微分析中各种制剂的固定剂、消毒剂、杀菌剂、还原剂。 安全措施 贮于阴凉干燥处，远离火种、热源。与氧化剂、酸碱类等分储分运。皮肤(眼睛)接触，用流动清水冲洗。 灭火：雾状水、抗溶性泡沫、干粉、二氧化碳、砂土。
室内空气中甲醛的取样与测定AHMT分光光度法
. 实验三室内空气中甲醛的取样与测定——AHMT分光光度法 一、实验提要 甲醛（HCHO）无色气体，易溶于水和乙醇。甲醛对皮肤和粘膜有强烈的刺激作用，可使细胞中的蛋白质凝固变性，抑制一切细胞机能，由于甲醛在体内生成甲醇而对视丘及视网膜有较强的损害作用。甲醛对人体健康的影响主要表现在嗅觉异常、刺激、过敏、肺功能异常及免疫功能异常等方面。 室内空气中甲醛主要来源于室内装饰的人造板材、人造板制造的家具、含有甲醛成分并有可能向外界散发的其他各类装饰材料及燃烧后会散发甲醛的材料。 3。0.10mg/m 室内空气质量标准规定甲醛的最高允许含量为空气中甲醛的测定方法主要有AHMT分光光度法、乙酰丙酮分光光度法、酚试剂分光光度法、气相色谱法、电化学传感器法等。 1.实验目的 （1）了解和掌握室内空气中甲醛的采样方法； （2）了解室内空气中甲醛的测定方法，掌握AHMT分光光度法测定甲醛的方法。 2.实验原理 空气中甲醛与4-氨基-3-联氨-5-巯基-1，2，4-三氮杂茂在碱性条件下缩合，然后经高碘酸钾氧化成6-巯基-5-三氮杂茂[4，3-b]-S-四氮杂苯紫红色化合物，其色泽深浅与甲醛含量成正比。 AHMT分光光度法测定范围为2mL样品溶液中含 0.2～3.2 μg甲醛。若采样 流量为1L/min，3。0.01~0.16 mg/m 采样体积为20L，则测定浓度范围为 测定甲醛时，乙醛、丙醛、正丁醛、丙烯醛、丁烯醛、乙二醛、苯（甲）醛、甲醇、乙醇、正丙醇、正丁醇、仲丁醇、异丁醇、异戊醇、乙酸乙酯无影响；二氧化硫共存时，使测定结果偏低。因此对二氧化硫干扰不可忽视，可将气样先通过硫酸锰滤纸过滤器，予以排除。 二、仪器、试剂及材料 1.仪器材料 （1）空气采样器：流量范围0～1 L/min； （2）多孔玻板吸收管：10 mL容量、棕色； （3）10mL具塞比色管； （4）可见光分光光度计。 2.试剂 (1) 吸收液：称取1g三乙醇胺、0.25g偏重亚硫酸钠和0.25g乙二胺四乙酸二钠溶于水中并稀释至1000mL。 1 / 7 . （2）0.5% 4-氨基-3-联氨-5-巯基-1，2，4-三氮杂茂（简称AHMT）溶液：称取0.25gAHMT溶于0.5mol/L盐酸中，并稀释至50mL，此试剂置于棕色瓶中，可 保存半年。 （3）5mol/L氢氧化钾溶液：称取28.0g氢氧化钾溶于100mL水中。 （4）1.5%高碘酸钾溶液：称取1.5g高碘酸钾溶于0.2mol/L氢氧化钾溶液中，并稀释至100mL，于水浴上加热溶解，备用。
甲醛及其检测方法的研究进展
方面可能具有更为重要的意义。将来人们重点将是对这些调节途径的详细信号机制的探索,明确这些机制对掌握许多疾病的发生机制、选择针对性治疗手段具有重要的意义。 参考文献: [1] W ang G L,Jiang BH,Rue E A,et al.Hypoxia2inducible factor1is a ba2 sic2helix2loop2helix2PAS heterodimer regulated by cellular O2tension[J]. Proc Natl Acad Sci US A,1995,92(12):5510-5514. [2] M axwell PH,W iesener MS,Chang G W,et al.The tum our suppress or protein VH L targets hypoxia2inducible factors for oxygen2dependent prote2 olysis[J].Nature,1999,399(6733):271-275. [3] Berra E,Benizri E,G inouves A,et al.HIF prolyl2hydroxylase2is the key oxygen sens or setting low steady2state levels of HIF21alpha in norm oxia [J].E M BO J,2003,22(16):4082-4090. [4] M cNeill LA,Hewits on K S,G leadle JM,et al.The use of dioxygen by HIF prolyl hydroxylase(PH D1)[J].Bioorg M ed Chem Lett,2002,12 (12):1547-1550. [5] M etzen E,Zhou J,Jelkmann W,et al.Nitric oxide im pairs norm oxic degradation of HIF21alpha by inhibition of prolyl hydroxylases[J].M ol Biol Cell,2003,14(8):3470-3481. [6] Haddad JJ,Land SC.A non2hypoxic,ROS2sensitive pathway mediates T NF2alpha2dependent regulation of HIF21alpha[J].FE BS Lett,2001,505 (2):269-274. [7] Zhong H,Chiles K,Feldser D,et al.M odulation of hypoxia2inducible factor1alpha expression by the epidermal growth factor/phosphatidyli2 nositol32kinase/PTE N/AK T/FRAP pathway in human prostate cancer cells:im plications for tum or angiogenesis and therapeutics[J].Cancer Res,2000,60(6):1541-1545. [8] Laughner E,T aghavi P,Chiles K,et al.HER2(neu)signaling increases the rate of hypoxia2inducible factor1alpha(HIF21alpha)synthesis:novel mechanism for HIF212mediated vascular endothelial growth factor expres2 sion[J].M ol Cell Biol,2001,21(12):3995-4004. [9] Jung Y J,Isaacs JS,Lee S,et al.I L21beta2mediated up2regulation of HIF2 1alpha via an NFkappaB/COX22pathway identifies HIF21as a critical link between in flammation and oncogenesis[J].FASE B J,2003,17(14): 2115-2117. [10] Qian D,Lin HY,W ang H M,et al.N orm oxic induction of the hypoxic2 inducible factor21alpha by interleukin21beta inv olves the extracellular signal2regulated kinase1/2pathway in normal human cytotrophoblast cells [J].Biol Reprod,2004,70(6):1822-1827. [11] S troka DM,Burkhardt T,Desbaillets I,et al.HIF21is expressed in nor2 m oxic tissue and displays an organ2specific regulation under systemic hy2 poxia[J].FASE B J,2001,15(13):2445-2453. [12] K im CH,Cho Y S,Chun Y S,et al.Early expression of my ocardial HIF2 1alpha in response to mechanical stresses:regulation by stretch2activated channels and the phosphatidylinositol32kinase signaling pathway[J].Circ Res,2002,90(2):E25-33. [13] K uwahara F,K ai H,T okuda K,et al.Hypoxia2inducible factor21alpha/ vascular endothelial growth factor pathway for adventitial vasa vas orum formation in hypertensive rat aorta[J].Hypertension,2002,39(1):46 -50. (收稿日期:2004-07-07 修回日期:2004-10-25) 文章编号:1000-6486(2005)01-0055-03【综 述】甲醛及其检测方法的研究进展 张志虎, 邵华 关键词:甲醛;检测方法 中图分类号:R134+.4 文献标识码:A 甲醛广泛存在于环境中,对机体有诸多不利的影响。随着 生活水平的提高和卫生意识的增强,人们现在越来越关注它在 环境中的存在(尤其是在室内装修方面),因此对它的研究也较多。国内外建立了许多空气中甲醛的检测方法,而对甲醛的生 物检测方法研究却很少,本文旨在探索有效的检测方法。 1 甲醛的理化性质 甲醛常温下是一种无色、具有强烈刺激性的气体,易溶于水,比重01815,沸点-1915℃。其40%的水溶液称为福尔马林,它能使蛋白凝固,具有杀菌和防腐作用,常用来保存动物标本。甲醛的化学性质很活泼,能和氢氰酸、亚硫酸氢钠、氨的衍生物(如2,4-二硝基苯肼、苯肼、羟胺等)以及醇类发生加成 基金项目:国家自然科学基金资助(30471429);山东省自然科学基 金资助(Y2002C30) 作者单位:山东省劳动卫生与职业病防治研究院,山东济南250062 作者简介:张志虎(1973-),男,在读硕士研究生,主要从事职业卫 生和环境卫生研究 通讯作者:邵华反应;经催化氢化,甲醛被还原成甲醇;甲醛可以被氧化剂氧化生成甲酸;它在浓碱的作用下,能发生自身的氧化还原作用,此即所谓的歧化反应。 2 甲醛的来源 甲醛广泛存在于环境中,它有众多的来源:许多工业生产活动如石化工业、药物制造、燃煤工业等可产生甲醛;甲醛是树脂、橡胶、塑料等合成工业的重要原料;一些燃烧产物(如机动车尾气、烹调油烟、香烟烟雾等)、生活用品(如香水、喷发水、空气清新剂等)、建筑、装饰材料(如脲醛树脂、夹合板、粒子板、泡沫绝缘材料、油漆、染料、新家具等)也可产生甲醛;空气中碳氢化合物在光化学作用下可以生成甲醛。体内脂质的氧化或过氧化,丝氨酸、甘氨酸、胆碱等的代谢,以及一些脱甲基反应都可产生甲醛;甲醛还是嘌呤、胸腺嘧啶生物合成的中间产物。 3 甲醛的代谢 人体内的甲醛(包括外界进入的和内生的)有多种代谢途径,主要有:①经肺直接呼出;②进入尿液被排出[1];③与体内组织蛋白质、细胞DNA反应形成加合物而贮存在体内;④在肝脏和红细胞中的甲醛脱氢酶、醇脱氢酶的催化下,生成甲酸。
甲醛的危害及处理方法与研究
1 绪论 1.1 甲醛的危害及处理方法与研究进展 1.1.1 甲醛的性质 甲醛(俗称福尔马林，英文名Formaldehyde，别称蚁醛)，35%～40%的水溶液通常称福尔马林。甲醛是一种无色易溶于水的刺激性气体,当室内空气中含量为0.1 mg/m3时就有异味和不适感；当大于65mg/m3可以引起肺炎、肺水肿等损伤，甚至导致死亡。皮肤直接接触甲醛，可引起皮炎、色斑、坏死。经常吸入少量甲醛，能引起慢性中毒，出现粘膜充血、皮肤刺激症、过敏性皮炎、指甲角化和脆弱、甲床指端疼痛等。 1.1.2 甲醛的主要来源 大气中甲醛主要来源于工业生产以及广泛运用的塑料、橡胶、脉醛泡沫、树脂、隔热材料、豁合剂、皮革、纺织、制药、汽车尾气等。家庭室内甲醛主要来源于装饰材料。大量使用含醛的树脂、胶合板、细木工板、泡沫塑料和油漆以及香烟的燃烧、一些纺织品也可以向空气中释放甲醛气体。在实验室，解剖室中，甲醛是常用的组织防腐剂、消毒剂。建筑材料生产车间可能有高浓度的甲醛蒸汽。 生活饮用水中的甲醛主要来源于所接触的输配水管、蓄水容器、供水设备和漆酚、环氧(酚醛)树脂为涂料，内衬等防护材料的溶出及环境水的污染。食品中甲醛的主要来源，为不法商贩在水发食品中添加甲醛。废水中的甲醛主要来自有机合成、合成橡胶、油漆和涂料、塑料、制革、纺织以及木材粘合剂生产过程等。 1.1.3 甲醛对人体的危害 甲醛是公认的强毒性物质。对人和温血动物的毒性很强，当室内空气中甲醛超过国家规定的卫生标准(0.08mg/mL)，可引起眼部、上呼吸道刺激症、皮肤过敏反应以及变态反应。长期接触较高浓度的甲醛对呼吸系统、神经系统、肝脏、皮肤、免疫系统等都有一定的毒害作用。如果人类长期饮用被甲醛污染的水源，会引发头昏、贫血以及各种神经系统疾病，甲醛还有致畸、致癌作用。1995年国际癌症研究机构将甲醛确定为可疑致癌物[1]，寻求遗传毒性研究发现甲醛能引起基因突变和染色体损伤，这些均提醒人们甲醛污染已不容忽视，寻求有效治理方法以降解废水中甲醛己成为环境污染治理领域的热点。
室内空气中甲醛的取样与测定——AHMT分光光度法
实验三室内空气中甲醛的取样与测定——AHMT分光光度法 一、实验提要 甲醛（HCHO）无色气体，易溶于水和乙醇。甲醛对皮肤和粘膜有强烈的刺激作用，可使细胞中的蛋白质凝固变性，抑制一切细胞机能，由于甲醛在体内生成甲醇而对视丘及视网膜有较强的损害作用。甲醛对人体健康的影响主要表现在嗅觉异常、刺激、过敏、肺功能异常及免疫功能异常等方面。 室内空气中甲醛主要来源于室内装饰的人造板材、人造板制造的家具、含有甲醛成分并有可能向外界散发的其他各类装饰材料及燃烧后会散发甲醛的材料。 室内空气质量标准规定甲醛的最高允许含量为0.10mg/m3。 空气中甲醛的测定方法主要有AHMT分光光度法、乙酰丙酮分光光度法、酚试剂分光光度法、气相色谱法、电化学传感器法等。 1.实验目的 （1）了解和掌握室内空气中甲醛的采样方法； （2）了解室内空气中甲醛的测定方法，掌握AHMT分光光度法测定甲醛的方法。 2.实验原理 空气中甲醛与4-氨基-3-联氨-5-巯基-1，2，4-三氮杂茂在碱性条件下缩合，然后经高碘酸钾氧化成6-巯基-5-三氮杂茂[4，3-b]-S-四氮杂苯紫红色化合物，其色泽深浅与甲醛含量成正比。 AHMT分光光度法测定范围为2mL样品溶液中含 0.2～3.2 μg甲醛。若采样流量为1L/min，采样体积为20L，则测定浓度范围为 0.01~0.16 mg/m3。 测定甲醛时，乙醛、丙醛、正丁醛、丙烯醛、丁烯醛、乙二醛、苯（甲）醛、甲醇、乙醇、正丙醇、正丁醇、仲丁醇、异丁醇、异戊醇、乙酸乙酯无影响；二氧化硫共存时，使测定结果偏低。因此对二氧化硫干扰不可忽视，可将气样先通过硫酸锰滤纸过滤器，予以排除。 二、仪器、试剂及材料 1.仪器材料 （1）空气采样器：流量范围0～1 L/min； （2）多孔玻板吸收管：10 mL容量、棕色； （3）10mL具塞比色管； （4）可见光分光光度计。 2.试剂 (1) 吸收液：称取1g三乙醇胺、0.25g偏重亚硫酸钠和0.25g乙二胺四乙酸二钠溶于水中并
甲醛的检测方法与研究进展
第19卷第5期2009年10月 皮革科学与工程LEATHER SC I ENCE AND ENG I N EER ING V ol 119,N o 15O ct 12009 文章编号:1004-7964(2009)05-0033-03 甲醛的检测方法与研究进展 胡逸飞,张新申* ,俞凌云 (四川大学制革清洁技术国家工程实验室,四川成都610065) 摘要:甲醛含量是环境监测与皮革工业的一项重要指标。本文综述了国内外近些年来常用的甲醛测定的方法的优 缺点及其实际应用。 关键词:甲醛;检测方法;皮革 中图分类号:TS 57 文献标识码:A 收稿日期:2008-09-05 第一作者简介:胡逸飞(1988-),男,新疆乌鲁木齐市人,本科生,专业:轻化工程。 *通讯联系人,张新申,教授,博士生导师,E-m a i:l zhangx -i nsheng @126.co m 。 Research Progress i n AnalysisM et hods for For mal dehyde H U Yi -fei ,Z HANG X in-s hen * ,YU L ing-yun (N ational Engineering Laboratory for Cle an T echno l ogy of L eather M anufact ure ,S ic huan Uni versit y,Che ngdu 610065,Chi na )Abstrac t :The content o f fo r ma l dehyde is a very i m po rtant i ndex i n env iron m entalm onitor i ng and l ea t her i ndustry .T he re -cent co mmon de ter m i nati ons of f o r m aldehyde i n the wo rl d are briefl y su mma rized and t he ir practical appli ca tions a re dis -cussed . K ey word s :for m aldehyde ;analysis m ethods ;leather 甲醛是日益受到重视的环境污染物之一,在我 国有毒化学品优先控制名单,甲醛居第二位[1] 。甲醛对人体有害,主要因为甲醛可以和人体内的蛋白质结合,改变蛋白质的内部结构并使其凝固,因而 具有杀伤力[2] 。因此建立易操作,精密度高的甲醛测定方法尤其重要。 1 分光光度法 111 酚试剂分光光度法 鲍军等[3] 采用酚试剂分光光度法测定人造板及其制品、木家具的微量甲醛释放量(干燥器法)。甲醛浓度在0~3.50mg /L 范围内,与吸光度呈线性关系,相关系数为0.9993。检测灵敏度是GB 18584、GB /T 17657乙酰丙酮分光光度法的5倍,显色过程耗时约为后者的1/5,样品测定结果与乙酰丙酮分光光度法相符合。尤其对于甲醛释放量不 大于115mg /L 的样品,酚试剂分光光度法测定结果 的重复性好于乙酰丙酮光度法,测定结果的相对标准偏差小于乙酰丙酮光度法。112 变色酸分光光度法 变色酸法是测定甲醛的较为成熟的分析方法,美国职业安全卫生研究所N I O SH 把其列为标准的 分析方法(N I O SH 方法3500)[4] 。甲醛在浓硫酸溶液中与变色酸作用形成紫色化合物,检出限为011mg /L 。其中当乙醛在017m g 以下时不干扰测定,量大时使溶液发黄,醇共存时不干扰测定;酚含量 为2L g 以上时测定结果偏低[5] 。Petreas M 等提出了改良变色酸法,以1%的亚硫酸钠溶液吸收甲醛,变色酸浓度改为5%,使该法在应用中更稳定、更灵敏。 113 分光光度法测定微量甲醛 崔成民等[6] 研究了分光光度法测定微量甲醛的方法,并对显色剂的使用条件进行了系统研究,得出显色剂用量为1100mL 以上时,甲醛显色溶液的吸光度值基本保持稳定,此方法在测定食品等固形物中的甲醛有很好的应用。114 AHMT 法 AHMT 法 [7]指空气中的甲醛与AHMT (4-氨基-
甲醛的危害及其卫生检验方法
归方程为Y =010235+110541X ,r =019986。212 精密度实验 取标准溶液110、015ml 用苯:石油醚=1∶1溶解稀释至10ml 配成高低两种浓度溶液,测定6次,各样的相对标准偏差在5%以内,满足分析要求。213 回收率测定实验 在测定精密度的实验中,将标准测定值与真值比较,标准样品的平均回收率范围在95%～105%。实际样品加标回收测定:取3份样品分别测定其本底含量及加015ml 标准液后的含量,计算回收率,范围在80105%～110%。214 两种升温方法测定结果比较 用恒温法和程序升温法,测定6份保健食品样品和两份标样,测定结果进行平均差数t 检验,计算结果表明,两种升温方法测定结果差异无显著性,本文采用恒温法。215 实际样品的分析 用该法测定送检样品,其γ-亚麻酸标准及样品气相色谱图如图1 。 图1 γ-亚麻酸标准及样品气相色谱图a 1γ-亚麻酸标准图 b 1样品图 样品与γ-亚麻酸标准品比较,相对应的γ-亚麻酸见 表1。 表1 样品γ-亚麻酸含量测定结果 批号 保留时间(min ) γ-亚麻酸含量(%) 020*******.57 5.330200120216.54 5.5402001203 16.56 5.46 由以上分析结果可看出,样品中亚麻酸含量达5%以上。3 讨论 气相色谱分析保健食品中亚麻酸的含量存在一定的困难,主要是由于γ-亚麻酸的含量较高,不易与其相邻峰达到基线分离。为了提高柱效、改善分离度、准确测定γ-亚麻酸的含量,并采用程序升温的方法对保健食品中的亚麻酸进行分离,分离效果较好。 γ-亚麻酸沸点很高,难于用气相色谱直接分析,必须转化为挥发性衍生物,再将所得的自由脂肪酸脂化,使其极性下降,沸点降低,因而分离能上升,才能用气相色谱分析,否则其在气相色谱上的响应值很低,无法准确定量。 尝试了用12%～14%的三氟化硼甲醇溶液和014m ol/L 氢氧化钾甲醇溶液对样品进行甲脂化,经G C 分析比较,014m ol/L 氢氧化钾甲醇溶液,干扰峰少,提取较完全,样品响应值高,故选用014m ol/L 氢氧化钾甲醇溶液对样品进行甲脂化处理。本法简便、快速,能满足色谱分析的需要。 本文提供了一种快速、简便测定保健食品中γ-亚麻酸的分析方法,γ-亚麻酸的出峰时间为16155min 其他成分干扰少,运用于实测样品,证明方法准确、可靠,具有一定的实用价值。4 参考文献 [1]日本药学会,编著1卫生试验1注解.北京:华文出版社,199512711[2]韦业成1月见草油及胶囊中γ-亚麻酸的含量测定1药物分析杂志,1990,10(1):151 [3]沈小婉,李明元,叶世博,等1脂肪酸的测定1色谱法在食品分析中 的应用.北京:北京大学出版社,1992.57-601 (收稿:2003-04-21) (本文编辑:张军) 甲醛的危害及其卫生检验方法 徐向荣,徐增康 (陕西省疾病预防控制中心,西安市710054) 关键词 甲醛;危害;检验方法 中国图书资料分类号:R13 文献标识码:A 文章编号:1004-1257(2003)12-0047-03 甲醛(formaldehyde )是一种严重影响人类健康的环境污染物,因其毒性较大,目前,世界卫生组织(WH O )和美国环境保护局(EP A )均将甲醛列为潜在危险致癌物和重要环境污染物。1 甲醛的分子结构与特征 甲醛,化学式为HCH O ,俗名蚁醛。常温下是气体,具有特殊臭味。甲醛与其他醛不同,它的羰基碳原子和2个氢原子相连,性质上比其他醛活泼。甲醛在空气中能逐渐被氧化为甲酸,是强还原剂。2 甲醛的污染来源 加工生产室内装饰材料细木工板、中密度纤维板、刨花板和胶合板等木制人造板材中使用的粘合剂脲醛树脂和酚醛树脂,其主要原料是甲醛、尿素、苯酚和其他辅料,板材中残留的未参 与反应的有害物质如甲醛会逐渐向周围环境释放,形成室内空 气中甲醛的主体,从而对室内空气造成污染。研究表明,人造板材中甲醛的释放期一般为3～15a 。含有甲醛成分并有可能向外界散发的其他各类装饰材料还有壁纸、化纤地毯、泡沫塑料、 油漆和涂料等[1] 。装饰房间不同时间内空气中甲醛平均含量均显著地高于未经装修的对照房间,平均含量在01071～01170mg ?m -3之间,装饰后1a 内房间空气中甲醛的平均浓度为01114mg ?m -3。在装饰2a 以后室内空气中甲醛的平均含量可以降低到居室空气中甲醛的卫生标准(最高容许浓度)0108mg ?m -3[2]。甲醛在室内的浓度变化主要与污染源的释放量和释放规律有关,也与使用期限、室内温度、湿度及通风强度等因素有关,其中温度和通风的影响最为重要。有调查显示,大部分家具市场空
甲醛的测定 乙酰丙酮分光光度法
空气甲醛的测定乙酰丙酮分光光度法 1 适用范围：工业废气、环境空气和室内空气中甲醛的测定。 2 原理 甲醛气体经水吸收后，在pH=6的乙酸-乙酸铵缓冲溶液中，与乙酰丙酮作用，在沸水浴条件下，迅速生成稳定的黄色化合物，在波长413nm处测定。 3 最低检出浓度 本方法的检出限为0.25μg，在采样体积为30L时，最低检出浓度为0.008 mg/m3。 4 试剂 除非另有说明，分析时均使用符合国家标准的分析纯试剂和按(4.1)条制备的水。 4.1 不含有机物的蒸馏水：加少量高锰酸钾的碱性溶液于水中再行蒸馏即得（在整个蒸馏过程中水应始终保持红色，否则应随时补加高锰酸钾）。 4.2 吸收液：不含有机物的重蒸馏水。 4.3 乙酸铵（NH4CH3COO）。 4.4 冰乙酸（CH3COOH）：ρ=1.055。 4.5 乙酰丙酮溶液，0.25%（V/V）：称25g乙酸铵，加少量水溶解，加3mL冰乙酸及0.25mL新蒸馏的乙酰丙酮，混匀再加水至100mL，调整pH=6.0，此溶液于2℃~5 ℃贮存，可稳定一个月。 4.6 0.1000mol/L碘溶液：称量40g碘化钾，溶于25mL水中，加入12.7g碘。待碘完全溶解后，用水定容至1000mL。移入棕色瓶中，暗处贮存。 4.7 氢氧化钠（NaOH）。 4.8 1mol/L氢氧化钠溶液：称量40g氢氧化钠，溶于水中，并稀释至1000mL。 4.9 0.5mol/L硫酸溶液：取28mL浓硫酸（ρ=1.84g／mL）缓慢加入水中，冷却后，稀释至1000mL。 4.10 1+5硫酸：取40mL浓硫酸（ρ=1.84g／mL）缓慢加入200 mL水中，冷却后待用。 4.11 0.5%淀粉指示剂：将0.5g可溶性淀粉，用少量水调成糊状后，再加入100mL沸水，并煮沸2~3 min至溶液透明。冷却后，加入0.1g水杨酸或0.4g氯化锌保存。 4.12 重铬酸钾标准溶液：C(1／6K2Cr2O7)＝0.1000mol／L 准确称取在110～130℃烘2h，并冷至室温的重铬酸钾2.4516g，用水溶解后移入500mL容量瓶中，用水稀释至标线，摇匀。 4.13 硫代硫酸钠标准滴定溶液：c(Na2S2O3·5H2O)≈0.10mol／L。 称取12.5g硫代硫酸钠溶于煮沸并放冷的水中，稀释至1000mL。加入0.4g氢氧化钠，贮于棕色瓶内，使用前用重铬酸钾标准溶液标定，其标定方法如下： 于250mL碘量瓶内，加入约1g碘化钾及50mL水，加入20.0mL重铬酸钾标准溶液(4.12)，加入5mL硫酸溶液(4.10)，混匀，于暗处放置5min。用硫代硫酸钠溶液滴定，待滴定至溶液呈淡黄色时，加入1mL淀粉指示剂(4.11)，继续滴定至蓝色刚好退去，记下用量(V1)。 硫代硫酸钠标准滴定溶液浓度(mol／L)，由式(1)计算： 式中：C1——硫代硫酸钠标准滴定溶液浓度，mol／L； C2——重铬酸钾标准溶液浓度，mol／L； V1——滴定时消耗硫代硫酸钠溶液体积，mL； V2——取用重铬酸钾标准溶液体积，mL。
室内甲醛检测方法完整版
室内甲醛检测方法 HEN system office room 【HEN16H-HENS2AHENS8Q8-HENH1688】
室内甲醛检测方法 甲醛现在被各界普遍认为是室内第一污染，它的释放期较长，轻微超标时居住者不易察觉。超标四五倍时，居住者才能嗅出气味。找正规的检测机构做甲醛检测已成为现在入住新居的一项必不可少的程序。下面金标准小编介绍以下目前在测定甲醛常采用以下6种检测方法： 1、测定工业废气和环境空气中甲醛的乙酰丙酮分光光度法，本法使用与树脂制造、涂料、人造纤维、塑料、橡胶、染料、制药、油漆、制革等行业的排放废气以及做医药消毒、防腐、熏蒸时产生的甲醛蒸汽测定。测量范围在~800mg/m3。 2、测定居住区和公共场所空气大气中甲醛浓度的AHMT(4-氨基-3-联氮-5-硫基-1，2，4-三氮杂茂)分光光度法。测量范围为~m3。 3、适用于公共场所空气中甲醛浓度的酚试剂（MBTH）分光光度法，测量范围为~m3。 4、气相色谱法 5、用于测定纺织品中游离甲醛含量的水萃取法。适用为游离甲醛含量为 20mg/kg到3500mg/kg之间的纺织品。 6、用于测定纺织品中释放的甲醛含量的蒸气吸收法。适用为游离甲醛含量为20mg/kg到3500mg/kg之间的纺织品。 目前，甲醛气体的检测方法按精确度划分，大致可分为两种，其一种为精密度测定法（仪器分析法），包括世界卫生组织推荐的高效液体色谱法（HPLC），气相色谱法（DNPH-GC法）及分光光度法等；其二为简易测定法，该法主要用于快速检测，其精确度要求不高。主要有电法学方法，可以显示测定数据，以及检测管方式和测定纸方式，即通过检测气体与指示剂发生法学反应而表现出的颜色变化来测定检测气体浓度。 室内甲醛检测方法——酚试剂分光光度法 一、原理 空气中的甲醛与酚试剂反应生成嗪，嗪在酸性溶液中被高铁离子氧化成蓝绿色化合物，根据颜色深浅，比色定量。 二、仪器设备 1．气泡采样管或多孔玻板采样管； 2．QC-2A大气采样仪或TMP1500电子控时采样器； 3．10mL具塞比色管； 4．723型可见分光光度计。 三、药品试剂 本法中所用水均为重蒸馏水或去离子交换水，所用试剂纯度均为分析纯。 1．吸收原液(C(MBTH)=mL)：称量酚试剂(MBTH)，用水溶解后稀释至50mL(贮于冰箱中可稳定三天)。 2．吸收液(C(MBTH)=mL)：量取5mL吸收原液，用水稀释至100mL(采样时，临用现配)。 3．L盐酸：量取浓盐酸(C摩(mol/L)=C质(%)×ρ总(g/mL)× 1000/M(g/mol)=12mol/L)，用水稀释至1000mL。 4．1%硫酸铁铵溶液：称量硫酸铁铵，用L盐酸溶解后稀释至100mL。 5．碘溶液(C(1/2I2)=L)：以下两种方法二选其一，若有可能，则优先采取第二个方法。一，准确称量40g碘化钾，溶于25mL水中，加碘，用水溶解后稀释至1000mL(移入棕色瓶中，暗处贮存)；二，外购试剂进行当量换算：精确量取外购碘