Occupational Health Analytical Chemistry

Quantitation of vanadium oxides in airborne dusts by x-ray diffraction

“…This methodology, which is used in the present work, employs sampling with a 10-mm nylon cyclone and 37-mm 5-pm pore size PVC-type filter, dissolution of the filter with tetrahydrofuran, redeposition onto 25 mm diameter, 0.45-µ pore size silver filters, followed by X-ray diffraction analysis using external standardization. Redeposition redistributes the analyte as a homogeneous deposit on the silver filter and also permits a straightforward correction algorithm for X-ray absorption, based on the reduction of intensity of the d = 2.359 Á silver diffraction line (10).…”

“…The major alterntive method is perchiorination (9)(10)(11)(12)(13)(14)(15) of PCBs to decachlorobiphenyl (DCB). Though isomer specificity is lost, enhanced sensitivity is attained since all PCB isomers are converted to DCB, and the ECD response to DCB is much greater than those for the PCB isomers observed most in samples (tetra-, penta-, and hexachlorinated).…”

“…The key to such a screening method is the quantitative perchiorination of microamounts of PCBs. There are three current reagents: antimony pentachloride (9-13,18), BMC reagent (9,10,15), and antimony pentachloride-iodine-sulfuryl chloride (10). These have been utilized to perchlorinate…”