Page:NIOSH Manual of Analytical Methods - 1024.pdf/1

 Rh Rh

METHOD: 1024, Issue 2

1000 ppm

lowest feasible; suspect carcinogen

gas; vapor density 1.9 (air = 1); BP –4.4 °C; explosive range 2.0 to 11.5% v/v in air

10 ppm; suspect carcinogen (1 ppm = 2.21 mg/m³ @ NTP)

butadiene; biethylene; divinyl

SAMPLING

SOLID SORBENT TUBE (coconut charcoal, 400- and 200-mg inseparate tubes) 0.01 to 0.5 L/min 5 L @ 100 ppm 25 L separate front and back tubes, chill below –4 °C at least two months for quality assurance blind spikes stored in a freezer 2 to 10 field blanks per set

ACCURACY

0.19 to 19 mg/m³ (25-L samples) 0.1% 0.060 ±11.32% MEASUREMENT GAS CHROMATOGRAPHY, FID 1,3-butadiene 4 mL methylene chloride; 30 min 1 µL 200 °C 250 °C see APPENDIX A helium nitrogen, 30 mL/min fused silica, 10 m × 0.50-mm ID, 1.8-µm CP WAX 57 CB (backflushable pre-column), and 50 m × 0.32-mm ID, Al2O3/KCl PLOT (see APPENDIX A) vapor-spiked sampling media 1 to 480 µg per sample 0.2 µg per sample 0.025

The working range is 0.02 to 100 ppm (0.04 to 220 mg/m³) for a 25-L air sample. At the higher levels, desorbed samples may require dilution. Below 0.9 mg/m³ (0.4 ppm), the desorption efficiency falls below 75% and allowance should be made for decreased accuracy.

Pentane, methyl acetylene, or vinylidene chloride may chromatographically interfere at high levels. High humidity (>80% RH) or other hydrocarbons present at permissible levels may significantly decrease the sampler’s capacity for 1,3-butadiene.

This revises Method S91 [1].