Simultaneous preconcentration and quantification of ultra-trace tin and lead species in seawater by online SPE coupled with HPLC-ICP-MS.

BACKGROUND: Tin and lead contamination is a global threat to marine ecosystems considering their species-specific toxicity, bioavailability and mobility. Hence simultaneous measurement of multiple tin and lead compounds at µg L-1 to pg L-1 levels in environmental water is always an indispensable but challengeable task. High performance liquid chromatography coupled with inductively coupled plasma mass spectrometry (HPLC-ICP-MS) is one of the most widely used choices for this purpose because of good sensitivity, strong separation power and good compatibility. Previous HPLC-ICP-MS methods based on a single elemental speciation strategy are low-efficiency and sensitivity-insufficient for a large set of unstable samples and interaction of multiple metal(loid)s down to ng L-1 levels. RESULTS: In this study, we developed a sensitive, efficient and environment-friendly analytical method for accurate quantification of inorganic and organic species of tin and lead simultaneously based on HPLC-ICP-MS with online integration of solid phase extraction (SPE). By using graphene oxide modified silica conditioned with 1 mM benzoic acid to enrich tin and lead species from 10 mL sample, detection limits were improved to 2-8 pg per liter due to satisfactory enrichment factors (522-2848 folds). The SPE-HPLC-ICP-MS method was applicable to quantification of ultra-trace tin and lead species at pg L-1 levels in uncontaminated seawater. Tributyltin was the only tin species detected at subnanograms per liter levels while Pb(II) was the only lead species detected at several nanograms per liter in thirteen coastal seawater samples collected in Hangzhou Bay, indicating light contamination of tin and lead. SIGNIFICANCE: Overall, the proposed SPE-HPLC-ICP-MS method is highly sensitive, efficient and environment-friendly that are fairly suitable to routine speciation analysis of tin and lead in environmental, food, and biological samples.

Simultaneous quantification of tin and lead species in Antarctic krill and fish by interfacing high-performance liquid chromatography with inductively coupled plasma mass spectrometry based on strong cation-exchange and Amphion columns.

Tin and lead are a global concern considering their species-dependent toxicity, bioavailability and transformation. Simultaneous speciation analysis of tin and lead is challenging for a large food capacity containing unstable species. Herein, we developed two sensitive methods for rapid quantification of tin and lead species in Antarctic seafood by high-performance liquid chromatography and inductively coupled plasma mass spectrometry based on strong cation-exchange and Amphion columns. Inorganic tin and lead, four organotin and two organolead compounds can be analysed in 16 min on a 10-cm Amphion II column (mobile phase: 4 mM sodium dodecyl benzene sulfonate at pH 2.0) with 0.02-0.24 µg L-1 detection limits. The method was applied to Antarctic krill and fish, demonstrating the presence of any tin and lead species down to µg kg-1 level. Overall, the proposed methods are sensitive, efficient and environment-friendly for routine speciation analysis of tin and lead in food samples.

Simultaneous measurements of Cr, Cd, Hg and Pb species in ng L-1 levels by interfacing high performance liquid chromatography and inductively coupled plasma mass spectrometry.

Toxicity, mobility, bioavailability and biofunctions of chromium, cadmium, mercury and lead are heavily dependent upon their specific chemical forms, leading to a high demand to metal speciation analysis rather than total quantification. Simultaneous speciation analysis of multiple metal(loid)s is attractive to a large sample capacity containing unstable analytes due to its economic and environmental advantages over the conventional single elemental strategies. In this work, an analytical method integrating online solid phase extraction into high performance liquid chromatography interfaced with inductively coupled plasma mass spectrometry (ICP-MS) to simultaneously preconcentrate and quantify Cr, Cd, Hg and Pb forms in pg L-1 levels in water was developed. Cr(III + VI), Cd(II), Hg(II), Pb(II), methylmercury (MeHg), ethylmercury (EtHg), and trimethyl (TML) and triethyl lead (TEL) were captured by the C18 adsorbent (equilibrated with 10 mL of 1.0 mM 2-hydroxyethanethiol at 10 mL min-1) and eluted by mobile phase (5.0 mM Cys at pH 2.0), then completely separated on the C18 column within 8.0 min and eventually determined by ICP-MS. Low limits of detection (0.001-0.007 ng L-1) and quantification (0.003-0.023 ng L-1), good relative standard deviations (<4%) and high enrichment factors (827-2656 folds) were obtained with good linearities. Three reference materials of total cadmium (GBW08602), total mercury (GBW08603) and total lead (GBW08601) in water were analyzed by the developed method to validate the accuracy with good agreement with certified values and satisfactory recoveries (92-100%). This method was proved feasible by the determination of Cr, Cd, Hg and Pb compounds in drinking water, river water, pond water and tap water.