1. Calibrate each personal sampling pump with a representative sampler in line.
2. Sample at an accurately known flow rate between 1 and 4 L/min for up to 8 h for a total sample size
of 200 to 1500 L for TWA measurements. Do not exceed a filter loading of ca. 2 mg total dust.
SAMPLE PREPARATION:
NOTE 1: The following sample preparation gave quantitative recovery (see EVALUATION OF
METHOD) [4]. Steps 4 through 9 of Method 7300 or other quantitative ashing
techniques may be substituted, especially if several metals are to be determined on a
single filter.
NOTE 2: The Appendix gives a microwave digestion procedure which may be necessary for
complete recovery of lead from some matrices, especially epoxy-based paint.
3. Open the cassette filter holders and transfer the samples and blanks to clean beakers.
4. Add 3 mL conc. HNO3
, and 1 mL 30% H2O2
and cover with a watchglass. Start reagent blanks at
this step.
NOTE: If PbO2
is not present in the sample, the 30% H2O2
need not be added [2,4].
5. Heat on 140 C hotplate until volume is reduced to about 0.5 mL.
6. Repeat two more times using 2 mL conc. HNO3
and 1 mL 30% H2O2
each time.
7. Heat on 140 C hotplate until ca. 0.5 mL liquid remains.
8. When sample is dry, rinse the watchglass and walls of the beaker with 3 to 5 mL 10% HNO3
. Allow
the solution to evaporate to dryness.
9. Cool each beaker and dissolve the residues in 1 mL conc. HNO3
.
10. Transfer the solution quantitatively to a 10-mL volumetric flask and dilute to volume with distilled
1. Calibrate each personal sampling pump with a representative sampler in line. 2. Sample at an accurately known flow rate between 1 and 4 L/min for up to 8 h for a total sample sizeof 200 to 1500 L for TWA measurements. Do not exceed a filter loading of ca. 2 mg total dust.SAMPLE PREPARATION:NOTE 1: The following sample preparation gave quantitative recovery (see EVALUATION OFMETHOD) [4]. Steps 4 through 9 of Method 7300 or other quantitative ashingtechniques may be substituted, especially if several metals are to be determined on asingle filter.NOTE 2: The Appendix gives a microwave digestion procedure which may be necessary forcomplete recovery of lead from some matrices, especially epoxy-based paint. 3. Open the cassette filter holders and transfer the samples and blanks to clean beakers. 4. Add 3 mL conc. HNO3, and 1 mL 30% H2O2 and cover with a watchglass. Start reagent blanks atthis step.NOTE: If PbO2 is not present in the sample, the 30% H2O2 need not be added [2,4]. 5. Heat on 140 C hotplate until volume is reduced to about 0.5 mL. 6. Repeat two more times using 2 mL conc. HNO3 and 1 mL 30% H2O2 each time. 7. Heat on 140 C hotplate until ca. 0.5 mL liquid remains. 8. When sample is dry, rinse the watchglass and walls of the beaker with 3 to 5 mL 10% HNO3. Allowthe solution to evaporate to dryness. 9. Cool each beaker and dissolve the residues in 1 mL conc. HNO3.10. Transfer the solution quantitatively to a 10-mL volumetric flask and dilute to volume with distilled
การแปล กรุณารอสักครู่..
