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

Abstract

A European directive was recently adopted limiting the use of hazardous substances such as Pb, Hg, Cd, and Cr(VI) in vehicle manufacturing. From July 2003 a maximum of 2 g Cr(VI) will be authorised per vehicle in corrosion-preventing coatings of key components. As no standardised procedures are available to check if produced vehicles are in agreement with this directive, the objective of this work was to develop analytical procedures for total chromium and Cr(VI) determination in these materials. The first step of this study was to optimise digestion procedures for total chromium determination in plastic and metallic materials by inductively coupled plasma mass spectrometry (ICP-MS). High resolution (HR) ICP-MS was used to examine the influence of polyatomic interferences on the detection of the (52)Cr(+) and (53)Cr(+) isotopes. If there was strong interference with m/ z 52 for plastic materials, it was possible to use quadrupole ICP-MS for m/ z 53 if digestions were performed with HNO(3)+H(2)O(2). This mixture was also necessary for digestion of chromium from metallic materials. Extraction procedures in alkaline medium (NH(4)(+)/NH(3) buffer solution at pH 8.9) assisted by sonication were developed for determining Cr(VI) in four different corrosion-preventing coatings by HPLC-ICP-MS. After optimisation and validation with the only solid reference material certified for its Cr(VI) content (BCR 545; welding dusts), the efficiency of this extraction procedure for screw coatings was compared with that described in the EN ISO 3613 standard generally used in routine laboratories. For coatings comprising zinc and aluminium passivated in depth with chromium oxides the extraction procedure developed herein enabled determination of higher Cr(VI) concentrations. This was also observed for the screw covered with a chromium passivant layer on zinc-nickel. For coating comprising a chromium passivant layer on alkaline zinc the standardized extraction procedure was more efficient. In the case of painted metallic plate, because of a reactive matrix towards Cr(VI), its extraction without degradation was difficult to perform.

TPC Proteins Are Phosphoinositide- Activated Sodium-Selective Ion Channels in Endosomes and Lysosomes

“…After digestion (10min, 60°C), the ionic composition was measured using a Thermo Scientific Finnigan Element inductively coupled with a plasma-high resolution mass spectrometer (ICP-HRMS)(Seby et al, 2003). …”

Quick and simple speciation analysis of chromium in cements

“…For voltammetric determinations of Cr(VI) in solid samples it is necessary to carry out Cr(VI) into the solution. The literature describes several methods of Cr(VI) extraction among which the following extraction mixtures should be mentioned: DTPA + (NH4)2SO4/NH4OH (Grabarczyk et al, 2006;Grabarczyk, 2008a), (NH4)2SO4/NH4OH (Séby et al, 2003), Na2CO3 + NaOH (Method 3060A), NaOH, K2HPO4 + KH2PO4 (Vitale et al, 1997), CO2, Na2CO3 (Panichev et al, 2003). Two extraction procedures using different extraction mixtures were selected in this work for analysis of cement samples: DTPA + (NH4)2SO4/NH4OH and Na2CO3 + NaOH, and they were designated as procedures A and B, respectively.…”

Simultaneous extraction and catalytic adsorptive stripping voltammetric measurement of Cr(VI) in solid samples

“…However, there are no certified reference materials for Cr(VI) containing insoluble Cr(VI) [14,35]. In connection with this certified reference materials certified only for total chromium were used to validate the proposed procedure.…”