Comparison of three sampling and analytical methods for the determination of airborne hexavalent chromium

Abstract

A field study was conducted with the goal of comparing the performance of three recently developed or modified sampling and analytical methods for the determination of airborne hexavalent chromium (Cr(VI)). The study was carried out in a hard chrome electroplating facility and in a jet engine manufacturing facility where airborne Cr(VI) was expected to be present. The analytical methods evaluated included two laboratory-based procedures (OSHA Method ID-215 and NIOSH Method 7605) and a field-portable method (NIOSH Method 7703). These three methods employ an identical sampling methodology: collection of Cr(VI)-containing aerosol on a polyvinyl chloride (PVC) filter housed in a sampling cassette, which is connected to a personal sampling pump calibrated at an appropriate flow rate. The basis of the analytical methods for all three methods involves extraction of the PVC filter in alkaline buffer solution, chemical isolation of the Cr(VI) ion, complexation of the Cr(VI) ion with 1,5-diphenylcarbazide, and spectrometric measurement of the violet chromium diphenylcarbazone complex at 540 nm. However, there are notable specific differences within the sample preparation procedures used in three methods. To assess the comparability of the three measurement protocols, a total of 20 side-by-side air samples were collected, equally divided between a chromic acid electroplating operation and a spray paint operation where water soluble forms of Cr(VI) were used. A range of Cr(VI) concentrations from 0.6 to 960 microg m(-3), with Cr(VI) mass loadings ranging from 0.4 to 32 microg, was measured at the two operations. The equivalence of the means of the log-transformed Cr(VI) concentrations obtained from the different analytical methods was compared. Based on analysis of variance (ANOVA) results, no statistically significant differences were observed between mean values measured using each of the three methods. Small but statistically significant differences were observed between results obtained from performance evaluation samples for the NIOSH field method and the OSHA laboratory method.

Determination of hexavalent chromium in exhaled breath condensate and environmental air among chrome plating workers

“…Furthermore, the website of the National Institute for Occupational Safety and Health (NIOSH) shows various protocols for determining Cr(VI) in environmental air [23], and a comparison of the different analytical methods [24]. The state of the art concerning the measurement of airborne Cr(VI) compounds in workplace aerosols and related samples has recently been reviewed [25].…”

Moving your laboratories to the field – Advantages and limitations of the use of field portable instruments in environmental sample analysis

“…Analysis with portable UV-vis and UV-vis/NIR spectrophotometers is very simple and despite relatively high detection limits, it is often performed, even for scientific purposes, which can be evidenced by examples of recently published reports (Almazán-Sánchez et al, 2014;Dimitroula et al, 2015;Duguma and Walton, 2014;Liu et al, 2014;Meng et al, 2014). Boiano et al (2000) found no statistically significant differences between the results derived from laboratory and field UV-vis spectrophotometric determinations of airborne hexavalent chromium. The mean recovery values were higher for the field method (96.0 712.9% for spiked samples and 98.4 7 6.7% for certified reference material) than for two laboratory based methods (90.4 78.2% and 94.9 76.4% for spiked samples; 84.3 71.9% and 94.2 79.9% for certified reference material).…”

Development of analytical procedures for determination of total chromium by quadrupole ICP?MS and high-resolution ICP?MS, and hexavalent chromium by HPLC?ICP?MS, in different materials used in the automotive industry

“…However, for pH between 4 and 5, Cr(VI) reduction into Cr(III) was evidenced [14,15]. Thus, it seems preferable to use more alkaline solutions such as phosphate buffer (pH 8) [16,17,18,19], ammonium/ammonia buffer (8<pH<9) [19,20,21,22], alkaline digestion with a carbonate/sodium hydroxide mixture (pH 12) [23,24,25,26,27], or sodium hydroxide at pH 13 [20,26]. Good extraction recoveries were obtained with the ammonium/ammonia buffer for various pure solid phases such as K 2 CrO 4 (s) or PbCrO 4 (s) [22] and no oxidation of Cr(III) into Cr(VI) was observed for experiments performed with trivalent chromium in the form of Cr 2 O 3 (s).…”