Measurement of Mercury Species in Whole Blood Using Speciated Isotope Dilution Methodology Integrated with Microwave-Enhanced Solubilization and Spike Equilibration, Headspace鈥揝olid-Phase Microextract

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• 作者：G. M. Mizanur Rahman ; Mesay Mulugeta Wolle ; Timothy Fahrenholz ; H. M. 鈥淪kip鈥?Kingston ; Matt Pamuku
• 刊名：Analytical Chemistry
• 出版年：2014
• 出版时间：June 17, 2014
• 年：2014
• 卷：86
• 期：12
• 页码：6130-6137
• 全文大小：453K
• 年卷期：v.86,no.12(June 17, 2014)
• ISSN：1520-6882

文摘

A biomonitoring method was developed for the determination of inorganic-, methyl-, and ethylmercury (Hg²⁺, CH₃Hg⁺, and C₂H₅Hg⁺, respectively) in whole blood by triple-spiking speciated isotope dilution mass spectrometry (SIDMS) using headspace (HS) solid-phase microextraction (SPME) in combination with gas chromatographic (GC) separation and inductively coupled plasma mass spectrometric (ICP-MS) detection. After spiking the blood sample with isotopically enriched analogues of the analytes (¹⁹⁹Hg²⁺, CH₃²⁰⁰Hg⁺ and C₂H₅²⁰¹Hg⁺), the endogenous Hg species were solubilized in 2.0 mol L^鈥? HNO₃ and equilibrated with the spikes using a microwave-enhanced protocol. The microwaved sample was treated with a 1% (w/v) aqueous solution of sodium tetrapropylborate (buffered to pH 5.2), and the propylated Hg species were sampled in the HS using a Carboxen/polydimethylsiloxane-coated SPME fiber. The extracted species were thermally desorbed from the fiber in the GC injection port and determined by GC-ICP-MS. The analytes were quantified, with simultaneous correction for their method-induced transformation, on the basis of the mathematical relationship in triple-spiking SIDMS. The method was validated using a bovine blood standard reference material (SRM 966, Level 2). Analysis of human blood samples demonstrated the accuracy and reproducibility of the method, which can detect the Hg species down to 30 pg g^鈥? in blood. The validity of the analytical results found for the blood samples was demonstrated using mass balance by comparing the sum of the concentrations of the individual Hg species with the total Hg in the corresponding samples; the latter was determined by isotope dilution mass spectrometry (IDMS) after decomposing the blood using EPA Method 3052 with single-spiking.