National Institute for Occupational Safety and Health

“ Units = μg analyte per sample Note: For a few of the compounds in this method the LOQ values, when compared to the preceding method development results, may appear higher. This can be explained by the fact that in the initial method development no recovery study was conducted at a level near or above the instrumentally determined LOQ recoveries for each analyte. ”

“ Inject a known amount (2 to 20 μL) of pure analyte, or calibration stock solution, directly onto front sorbent section with a microliter syringe. c. Ca p the tube. Allow to stand overnight. d. Deso rb (steps 5 through 7 ) and analyze together with working standards (steps 11 and 12) . e. Prepare a graph of DE vs. μg analyte recovered. 10. Analyze three quality control blind spikes and three analyst spikes to insure that the calibration graph and D E graph are in control. ”

“ Inject s am ple aliqu ot either m anu ally using solve nt flush technique o r with autosam pler. NOTE: If peak area is above the linear range of the working standards, dilute with CS 2, rean alyze and apply the appropriate dilution factor in calculations. Measure peak area.
CALCULATIONS: 13.
14.
Determ ine the ma ss, μg (correc ted for DE) , of analyte found in the sam ple front (W f) and back (W b) sorbent sec tions and in the average m edia blank front (B f) and back (B b) sorbent sections. NOTE: If W b > W f/10, report breakthrough and possible sample loss. ”