Determination of Mercury in Urine and Seawater by Flow Injection Vapor Generation Isotope Dilution Inductively Coupled Plasma Mass Spectrometry

Abstract

A simple and inexpensive laboratory‐built vapor generator was used with inductively coupled plasma mass spectrometry (ICP‐MS) for the determination of mercury in urine and seawater samples. The applications of vapor generation ICP‐MS alleviated the non‐spectroscopic interferences and the sensitivity problem of mercury determination encountered when the conventional pneumatic nebulizer was used for sample introduction. The concentration of mercury was determined by isotope dilution method. The isotope ratio of mercury was calculated from the peak areas of each injection peak. The repeatability of the peak areas and isotope ratio determinations of seven consecutive injections of 1 ng mL−1 Hg solution were 2.3% and 2.2%, respectively. This method has a detection limit of 0.07 ng mL−1 for mercury. This method was applied to determine mercury in a CASS‐3 nearshore seawater reference sample, NASS‐4 open ocean seawater reference sample, NIST SRM 2670 freeze‐dried urine reference sample and several urine and seawater samples collected from National Sun Yat‐Sen University. The results for the reference samples agreed satisfactorily with the reference values. Results for other samples analyzed by the isotope dilution method and the method of standard additions agreed satisfactorily. Precision was better than 10% for most of the determinations.

Flow techniques in the analysis of biological samples by inductively coupled plasma mass spectrometry – a review

“…Various solutions for urine sample preparation based on ow techniques are described below. 36,39,40,43,[50][51][52][53][54][55][56]58,59,[61][62][63][64][65][66][67][68]70,71,80,81,[83][84][85][86][87][88] All of them allow each step of the analytical procedure to be performed in an automated way and reproducible manner.…”

“…The importance of the ow technique as a sample introduction system to ICP-MS in hydride generation (HG) and other vapour generation techniques is impossible to ignore, and such a connection was applied in many other methods of urine analysis. 39,[85][86][87][88] In the determination of As in urine CRMs, Huang et al 85 applied FI sample introduction to minimise the deposition of solids on the sampling orice caused by high salt content. The used system was assembled using a six-port injection valve (Rheodyne 50) with a 200 mL sample loop and a peristaltic pump delivering carrier solution (0.05 mol L −1 HNO 3 ).…”

“…The importance of the flow technique as a sample introduction system to ICP-MS in hydride generation (HG) and other vapour generation techniques is impossible to ignore, and such a connection was applied in many other methods of urine analysis. 39,85–88…”

“…The developed method was very sensitive and selective, and its validity has been demonstrated for the direct determination of sub-ppb levels of Cd in urine. In Wei and Jiang's work 88 dedicated to the determination of mercury in urine and seawater samples, a FI-VG sample introduction system and solution of 1% HCl and 1% l -cysteine used as a carrier appeared to be better than continuous nebulisation because no memory effects were observed. The applied FI system was simple and made of a six-port injection valve (Rheodyne 50) with a 200 μL sample loop and peristaltic pump (Gilson Minipuls 2).…”