Document LJ26ekEp0nYjmXpaNM9z4opn7

4 Designation: D 3335 - 05a Standard Test Method for LOW CONCENTRATIONS OF LEAD, CADMIUM, AND COBALT IN PAINT BY ATOMIC ABSORPTION SPECTROSCOPY1 Thnnandnid it iuued under the Seed designation D MJ3: thenuinber iminrdtjteh following the designation indicates the sear of original adoption or. in the case of revision, the >earoTlat revision. a number in parentheses indicates the tear of last rrapproval A superscript rpulon () indicates an editorial change liner the Ian rtviiion or tcapprovil. 1. Scope 5 .a D1193 Specification for Reagent Water* 1.1 This test method coven the determination of lead* contents between 0.0r and 555, cad mium contents between 50 and. 150 ppm (mg/ D2S32 Guide for Determining Volatile and Nonvolatile Content of Paint and Related Coatings* kg), and cobalt contents between 50 and 2000 ppm (mg/kg) present in the nonvolatile portion of liquid coatings or contained in dried films. There is no reason to believe that higher levels of all three elements could not be determined by this test method, provided that appropriate dilulions and adjustments in specimen size and re 3. Summary of Method 3.1 The specimen of liquid coating or dried* film is prepared for analysis by dry ashing. The content of lead, cadmium, or cobalt of an acid extract of the ash is determined by atomic ab sorption spectroscopy. agent quantities are made. 1.2 Only pigmented coatings were used for evaluating this test method, but there is no reason to believe that varnishes and lacquets could not be analyzed successfully, provided that appropri ate precautions are taken. 1.3 This test method is not applicable to the detennination of lead in samples containing an timony pigments (low recoveries are obtained). 4. Significance and Use 4.1 The permissible level of heavy metals in certain coatings is specified by governmental reg ulatory agencies. This test method provides a fully documented procedure for determining low concentrations of lead, cadmium, and cobalt present in both water and solvent-reducible coat ings to determine compliance. 1.4 If lead is present in the sample to be analyzed in the form of an organic lead com pound at a concentration greater than 0.1 %, small losses of lead may occur, resulting in slightly poorer precision than shown in Section 12. 1.5 This standard may involve hazardous ma 5. Apparatus 5.1 Atomic Absorption Spectrophotometer. consisting of an atomizer and either a single- or three-slot burner, gas pressure regulating and me tering devices for air and acetylene; lead, cad mium. and cobalt source lamps* with a regulated terials. operations, and equipment. This standard does not purport to address all ofthe safety prob lems associated with its use. It is the responsibil ity of whoever uses this standard to consult and establish appropriate safety and health practices anddetermine theapplicabilityofregulatory limi 1 This int method under (he jurisdiction of ASTM Commince INI on hint and Related Coatings and Materials and * the direct responsibility of Subcommittee 001.21 on Analysis of Paints and Paint Materials. Current edition approved July 16 and Nov 29. 1985. Pub listed January I9B6. Originally published as D 3335 - U* previous edition D 3335 -14. tations prior to use. Specific precautionary state ments are given in Section 7. * Vandeberi. J. T.. Stafford. H. O.. and Scon. K w,, termination of Low Concentrations of Lead in Paint* Jouf** ..rpjtm Tnknuiw. VoJ 47. No. 60*. May I9'}. 1 Annua of .4ST\t SlurufjrJs. Vol 06.03. 2. Applicable Documents 2.1 ASTM Standards: * Ar.ruai $,vk vf ASTM Standards. Vol 06 01 'Both hollow cathode lamps and eiectrodeleu ditchaTP lamps have been found satisfactory for this purpose. J646 0007-SWP-000007199 v & ft' a a D3335 jonsunt-currem supply. a monochromator and usociated optics: a photosensitive detector con certed to an electronic amplifier, and a readout device. 5.2 Muffle Furnace, capable or maintaining 500* lore. 5.3 Crucibles, wide-form. porcelain, glazed in side and outside except for the outside bottom surface, approximately 30-mL capacity, 50-mm rim diameter and 31-mm height.* 5.4 Hot Plate, with variable surface tempera ture control over the range from 70 to 200*C. 5.5 High-Silica Glass Beakers100 and 250mL. 5.6 Volumetric Flasks. 50.100. and 1000-mL 5.7 Dropping Bottles, V* or *A-oz (7 or 15-mL) capacity. 5.8 Glass or Disposable Syringes, 5 or 10-mL capacity. . 5.9 Pipets. 1.2.5, and 10-mL capacity. 5.10 Paitu Shaker. 5.11 Paint Draw-Down Bar. * 6. Reagents 6.1 Purity ofReagents--Reagent grade chem icals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents shall conform to the specifications of the Committee t Analytical Reagents of the American Chemi cal Society, where such specifications are avail able.* Other grades may be used, provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening the accuracy of the determination. 6.2 Purity of Hater--Unless otherwise indi cated. references to water shall be understood to mean reagent grade water conforming to T>pe II ofSpecification D 1193. 6.3 Ammonium Acetate Solution <50 % weight/volume)--Dissolve 500 g of ammonium acetate (NbLC-HjOj) in water and dilute to 1 L 6.4 Ammonium Acetate Diluting Solution-- Add 50 mL of HNO, (sp gr 1.42) to 150 roL of 50 % weight/volume ammonium acetate solu tion and dilute to 1 L 6.5 Cadmium StandardStock Solution {l mg/ mL)--Dissolve 2.1032 g of cadmium nitrate (Cd(NOj),) in 10 mL of water, add 10 mL of HNOj (sp gr 1.42), and dilute to I L 6.6 Cobalt Standard Stock Solution (1 mg/ mL)--Dissolve 4.9387 g of cobalt nitrate hexahydrate (Co (NOj )j -6Hj O) in 10 mL of water. add 10 mL of HNOj (spgr 1.42). and dilute to 1 L 6.7 Lead Standard Stock Solution (1 mg/ mL)--Dissolve 1.5980 g of lead nitrate (Pb(NO,h) in 10 mL of water, add 10 mL of HNOj (sp gr 1.42). and dilute to 1 L. No t e 1--10.00 mg/mL concentrations of cad mium. lead, silver and zinc are available as SRM 2121: and the same concentration of cobalt, copper, iron and nickel as SRM 2124 from: Ofiice ofStandard Reference Materials. Room B-JI1. Chemistry Building National Bureau of Standards. Washington. DC 20234. 6.8 A'itric Acid (sp gr 1.42)--Concentrated ni tric acid (HNOj). 6.9 A'itric Acid (1+1)--Add 1 volume of HNOj (sp gr 1.42) to I volume ofwater. 7. Safety Precautions 7.1 Concentrated nitric add is corrosive and may cause severe burns of the skin *or eves; the vapor is irritating to mucous membranes. Use care in handling this aridic substance. Refer to suppliers* Material Safety Data Sheet 7.2 Use only a rubber bulb aspirator for pipeting liquids. 8. Calibration and Standardization 8.1 Prepare 100-mL quantities of at least four standard solutions bracketing the expected lead, cadmium, or cobalt concentration in the sample to be tested. To suitable aliquots ofthe 1 mg/mL standard lead, cadmium, or cobalt solution, add 5 mL of HNO, (sp gr l .42) and 15 mL of 50 % ammonium acetate solution. Dilute to 100 mL with water. 8.2 Operational instructions for atomic ab sorption spectrophotometers vary with' different models. Consult the manufacturer's literature for establishing optimum conditions for the specific instrument used. 8.3 Turn the instrument on and set the wave length to the 283.3-nm lead line, the 228.8-nm cadmium line, or the 240.7-nm cobalt line. Apply the current recommended by the manufacturer * Coon No. 25007 crucibles. or wainlni. have ban found uiiifKioo for this purpose. ' Vror beakers manufactured by the Coming Glut Co. ban bon found satisfactory fee this purpose. 1 -Rcsjent Chemicals. American Chemical Society Specifi cations." Am. Chemical Soc. Washington, DC. for suizcstions on the testing et reagents not lined by the Ameriosn Chemical Society, tee 'Reapent Chemicals and Standards." by Joseph Rosin. D. Van Nonrmnd Co. lac. Nen York. KY. and the "Uniled Suits Pharmacopeia." 647 0007-SWP-000007200 r-l*S |V # 03335 to the lead, cadmium, or cobalt source lamp. Allow the instrument to warm up for about 15 min and set the slit width. Adjust the air and acetylene pressure or (low rates and ignite the burner in accordance with the manufacturer's instructions. 8.4 Aspirate water to rinse the atomizer cham ber. Aspirate a standard solution and make any necessary readjustment in instrument parameters to obtain maximum absorption. 8.5 Aspirate each of the appropriate standard solutions and record the corresponding instru ment readings. Aspirate water between each standard. 8.6 Construct a calibration curse on linear graph paper by plotting the absorbance versus concentration (micrograms per millilitre) for each standard solution. Alternativ ely, the calibra tion results may be stored in the instrument, if so equipped, and readings made directly in con centration. 9. Procedure 9.1 If the sample is a liquid coating, mix it until homogeneous, preferably on a mechanical shaker. Determine the nonvolatile content in accordance with Guide D 2832. 9.2 Prepare at least two replicate specimens by weighing by difference from a dropping bottle or syringe approximately 2 to 3 g of the mixed liquid coating, or by directly weighing approxi mately 1 to 2 g ofdried paint film, into a 30-mL porcelain crucible. Weigh to 0.1 mg. No t e I--The specimen size called for will give a concentration of approximately 10 to 20 pg/mL lead in the final diluted solution Tor paints containing ap proximately 500 ppm (mg/kg) lead, based on the solids. Ifthe material is estimated to contain mote or less than 500 ppm lead, the quantity taken should be adjusted accordingly. In the event that significantly less than 500 ppm lead is expected, a 250-mL high-silica beaker may be used in place of the crucible to accommodate spec imen weights up to 10 g. The size specified will give a concentration ofapproximately 2 to 4 pg/mL cadmium in the final diluted solution for paints containing ap proximately 100 ppm cadmium, based on the solids. The size specified will give a concentration of approxi mately 10 to 20 pg/mL cobalt in the final diluted solution for paints containing approximately 500 ppm cobalt, based on the solids. No t e 2--Recover dried paint films from previously coated substrates (being careful not to remove any underlying material from the substrate) or prepare in the laboratory from liquid samples. For the laboratory preparation, flow some of the well-mixed sample onto a clean glass plate. The use ofa paint drawdown bar is recommended to obtain a uniform wet film thickness not exceeding 2 mils (50 pm). Allow the film to dry in an even at I05*C for a minimum of I h. Scrape'the dried film olT the glass plate, preferablv with a single edge razor blade. 9.3 Place the crucible (or beaker) containing the liquid coating on a hot plate and slowly increase the temperature until the material is dried. With some types of coatings, an initial oven-drying at I0J*C may be necessary to re move solvents without incurring losses due to spattering. 9.4 When the specimen appears to be dry or when starting with a dried film., gradually* in crease the temperature of the hot plate until the material chan. 9.5 After charring is complete, place the con tainer in a preheated muffle furnace and ash at 475 to SOO'C. No t e 4--Ashing at temperatures in excess of 500*C may result in the loss of some lead by volatilization. 9.6 When the ashing appears to be complete (do not exceed I to 2 hk remove the crucible or beaker from the muflle furnace and allow- it to cool to room temperature: Break up the ash into fine panicles with a glass stimng rod. leaving the rod with the container through the filtering step. 9.7 Add 10 mL of HNOj (1+1), taking care to avoid losses due to spattering in case the ash reacts vigorously with the arid. Heat carefully on a hot plate until 2 to 3 mL of solution remain. Add an additional tO mL of HNOj (1+1) and continue heating on the hot plate until less than 5 mL of the solution remains. 9.8 Filter the solution ihrough medium-po rosity filter paper into a 50-mL volumetric flask. If the filtrate is not clear, refiller through fineporosity filter paper. Wash the container three times with 2.5 mL of hot ammonium acetate solution (6.3). each time transferring the wash ings to the filter paper. Wash the filter paper several times with water. Adjust the volume to 50 mL with water and mix. 9.9 Aspirate the test solution and determine the absorbance in the same manner in which the instrument w-as calibrated. Determine the con centration of lead, cadmium, or cobalt in micrograms per millilitre from the calibration curve. If the absorbance is above the range covered by the calibration curve, dilute an aliquot of the sample solution to a suitable volume with ammonium acetate diluting solution. No t e 5--For maximum accuracy, calibration and standardization (Section Si should be completed jud pnorto. Non used to method known s. sigmfirai and calc tions. cc spectrow ir.strumt- i- : ; ; : 10. Cal i 10.1 | lead, ca i:; .. tionof L: lead, eac : where: s: C F* 5000 ' AT 5* 11. Re 111 tent of whethe coating | j \ 12. Pr ( 12.1 f interla' laborat The, irt any peurm n This if not re standard ftsponu ntake i o 648 0007-SWP-000007201 y the tk- * -vly is -ial reto or 10-be Qat -c =ie or to -nto ihe ep. are ash os an. nd us so sk. ie-ee lie ^ h-'' er to ne ne noir ie le m 10 aspirating the sample solution. ^ NoTr 0--The method orsundard additions max be pied to improve the accuracy of the analysts. This method is particularly recommended for use with un sown samples where matrix elfecu may be potentially pgnilicant. For a deuilcd description of the procedure and calculations used in the method of sundard addi tions. consult a sundard text on atomic absorption spectroscopy or the instruction manual provided by the instrument manufacturer. 10. Calculation 10.1 Calculate the mean concentration of lead, cadmium, or cobalt in the nonvolatile por tion of the sample as follows: lead, cadmium or cobalt, ppm (mg/kg) in nonvolatile MCxfxSOOOl/IATxS) v. .-.ere: C " concentration oflead. cadmium, or co balt in the aspirated specimen solution. (pg/mL), F m dilution factor from 9.9 (volume diluted to/volume ofaliquot), 5000 factor derived from multiplying the 50mL volume obtained in procedure in 9.8 bv 100 (to convert AT used to a whole number) and 10* (to obtain ppm), then dividing by 10* (to convert grams ofsample to pg). AT percent nonvolatile ofpaint sample (use 100 if sample was a dried film), and 5 sample, g. 11. Report 11.1 Report the lead, cadmium, or cobalt con tent of the nonvolatile content ofthe sample and whether the analysis was conducted on a liquid coating or a dried film. 12. Precision and Bias* ent days, four samples of water-reducible paints and four samples ofsolvent-reducible paints con taining from 0.01 to 5 5c lead. 50 to 150 ppm (mgAg) cadmium, and 50 to 2000 ppm cobalt. The wjthin-laboratory coefficient of variation was found to be 3.4 56 relative at 24 degrees of freedom for lead. 3.7 56 relative at 15 degrees of freedom for cadmium, and 3.3 56 relative at 21 degrees of freedom for cobalt. The between-laboratory coefficient ofvariation was 9.3 56 relative at 20 degrees of freedom for lead. 8.9 56 relative at 11 degrees of freedom for cadmium, and 5.5 56 relative at 17 degrees offreedom for cobalt. Based on these coefficients, the following criteria should be used for judging the acceptability of results at the 95 56 confidence level: 12.1.1 Repeatability--Two results, each the mean of duplicate determinations, obtained by the same operator on different days should be considered suspect if the)' differ by mote than 11 56 relative for all three metals. 12.1.2 Reproducibility--Two results, each the mean of duplicate determinations, obtained by operators in different laboratories should be con sidered suspect if they differ by more than 28 56 relative for lead or cadmium or by more than 17 % relative for cobalt. 12.2 Bias: 12.2.1 The true value for the amount oflead present in the solids of a coating should be be tween 97 and 111 56 of the experimental value. 12.2.2 The true value for the amount of cad mium present in the solids of a coating should be between 77 and 143 56 of the experimental value. 12.2.3 The true value for the amount ofcobalt present in the solids of a coating should be be tween 96 and 120 56 of the experimental value. 12.1 The precision estimates are based on an interlaboratory study in which seven different laboratories analyzed in duplicate, on two differ 'Supporting dau ore available on loan from ASTM Head- quanen. Rcquos RR: 001-1005. The American Scan\ far Testing andMaterials takes noposition respecting the validity ofanypatent rights assertedin connection mth any item mentioned >n this standard lsen atthti standard are expressly advised that determination ofthe validity ofany such patent nghii. and the risk ofinfringement atsuch ngtus. areentirely their own responsibility This Standard is subject le revision aa any time by the responsible technicalcommittee end must be reviewedeveryfive years and if not revised, either reopproved or withdrawn. Your comments ore invited either for rev ision of this standard or for additional standards and should be addressed to ASTM Headpuaners. four comments will receive careful consideration at a meeting ofthe responsible technical committee, which you mar mend Ifyoufed that your comments hove not received a fair hearing you should male your nrws known to the ASTM Committee on Standards. I9lt Pace St.. Philadelphia. Pa. ItiOJ.