Document renQG1Qrn4YJ2K38v6BNZ4MRq

FORMULA: Pb M.W.: 207.19 (Pb); 223.19 (PbO) ___________ LEM METHOD: 7105 ISSUED: 8/15/90 OSHA: 0.05 mg/m3 NI0SH: <0.1 mg/m3 [1] ACGIH: 0.15 mg/m3 PROPERTIES: soft metal; d 11.3 g/cm3; MP 327.5 *C; valences +2, +4 in salts SYNONYMS: vary depending upon the chemical form (elemental lead and lead compounds except alkyl lead): CAS #7439-92-1 (Pb); CAS #1317-36-8 (PbO). SAMPLING________________________________________________ MEASUREMENT SAMPLER: FILTER (0.6~lim cellulose ester membrane) FLOW RATE: 1 to 4 L/min VOL-MIN: 1 L @ 0.05 mg/m3 -MAX: 1500 L TECHNIQUE: ATOMIC ABSORPTION, GRAPHITE FURNACE ANALYTE: lead ASHING: cone. HN03, 3 mL; 30% H202, 1 mL; 140 'C FINAL SOLUTION: 10 mL 5% HNO3 SHIPMENT: routine WAVELENGTH: 283.3 nm SAMPLE STABILITY: stable FIELD BLANKS: 10% of samples _______________ ACCURACY........................ ........... RANGE STUDIED: not studied BIAS: not significant [2] GRAPHITE TUBE: pyrolytic coated INJECTION: 20 l*L + 10 J1L matrix modifier, DRY: 110 'C, 70 sec; CHAR: 800 C. 30 sec; ATOMIZE: 1800 *C, 5 sec. BACKGROUND CORRECTION: 02, H2 or Zeeman CALIBRATION: Pb^ in 5% HNO3 OVERALL PRECISION (sr): not determined RANGE: 0.05 to 1.0 pg per sample [2] ESTIMATED LOD: 0.01 |ig per sample [21 PRECISION (sr): not determined APPLICABILITY; The working range is 0.0002 to >1 mg/m3 for a 200-L air sample. If high concentrations are expected, the samples should be analyzed by flame AAS. The method is applicable to elemental lead, including Pb fume, and all other aerosols containing lead. This is an elemental analysis, not compound-specific. Aliquots of the sample may be analyzed separately for additional elements. INTERFERENCES: Use D2 or H2 continuum or Zeeman background correction to control molecular absorption. High concentrations of calcium, sulfate, carbonate, phosphate, iodide, fluoride, or acetate can be offest by an additional sample treatment step. OTHER METHODS: This revises and replaces P&CAM 214 (3). Method 7300 (ICP-AES) is an alternate analytical method. Method 7505 is specific for lead sulfide. Method 7082 is a flame AA method. 0 074854 coNFTDEN-rm 8/15/90 7105-1 NIOSH Manual of Analytical Methods METHOD: _710& ,LM 16. Perform a matrix spike of a sample occasionally to check for matrix interferences. If an adequate recovery is not obtained (85 to 115%), an alternate method of analysis should be used, such as flame AA or ICP. MEASUREMENT: 17. Set spectrophotometer as specified by the manufacturer and to conditions on page 7105-1. NOTE: An alternate wavelength is 217.0 nm [6]. Analyses at 217.0 nm have slightly greater sensitivity, but poorer signal-to-noise ratio compared to 283.3 nm. Also, nonatomic absorption is significantly greater at 217.0 nm, making the use of 02. H2 continuum, or Zeeman background correction mandatory at that wavelength. 18. Add matrix modifier to samples and standards in proper ratio of 2 to 1 (sample or standard to matrix modifier). 19. Analyze standards, samples, and blanks. Record absorbance readings. NOTE: If the absorbance value for the sample is above the linear range of the standards, dilute with 5% HNO3, reanalyze, and apply the appropriate dilution factor in the calculations. CALCULATIONS: 20. Using the measured absorbances, calculate/the corresponding concentrations (^ig/mL) of lead in the sample, Cs, and average media blank, Cjj, from the calibration graph. 21. Using the solution volumes (mL) of the sample, Vs, and media blanks, Vjj, calculate the concentration, C (mg/m^), of lead in the air volume sampled, V (L): C sVvs C= mg/mJ EVALUATION OF METHOD: Method S341 [5] was issued on October 24, 1975, and validated over the range 0.13 to 0.4 mg/m^ for a 180--L air sample, using generated atmospheres of lead nitrate [2). Recovery in the range 18 to 72 Jig Pb per sample was 98%, and collection efficiency of 0.8-lim mixed cellulose ester filters (Millipore Type AA) was 100% for the aerosols. Subsequent studies on analytical recovery of 200 Jig Pb per sample using flame AAS gave the results [31: Species Diaestion Method Analvtical. Recovery. Pb metal Pb metal PbO PbS Pb02 Pb02 Pb in paint* Pb in paint* HNO3 only HNO3 + h2o2 HNO3 only HNO3 only HNO3 only hno3 + h2o2 HNO3 only HN03 + h2o2 92 4 103 3 93 4 93 5 82 3 100 1 95 6 95 6 Standard Reference Material #1579, U.S. National Bureau of Standards. Additional collection efficiency studies were also done using Gelman 6N-4 filters for the collection of Pb fume, which had geometric mean diameter of 0.1 |im [3]. Mean collection efficiency for 24 sampling runs at flow rates between 0.15 and 4.0 L/min was >97 1 2%. Overall precision, sr, was 0.072 for lead nitrate aerosol [2,5] and 0.068 for Pb fume [3]. 8/15/90 7105-3 DO 07A8S5 confident* NI0SH Manual of Analytical Methods