Detection of trace levels of lead in aqueous liquids using extractive electrospray ionization tandem mass spectrometry

Abstract

a b s t r a c tA sensitive approach, based on semi-quantitative measurement of the characteristic fragments in multistage extractive electrospray ionization mass spectrometry (EESI-MS n ), was developed for fast detection of trace levels of lead in aqueous liquids including mineral water, lake water, tap water, energy drinks, soft drinks, beer, orange juice, and tea. A disodium ethylene-diamine-tetraacetic acid (EDTA) aqueous solution was electrosprayed to produce negatively charged primary ions which then intersected the neutral sample plume to generate anions of EDTA-Pb(II) complexes. The charged EDTA-Pb(II) complexes were characterized with multistage collision induced dissociation (CID) experiments. The limit of detection (LOD) using EESI-MS 3 was estimated to be at the level of 10 -13 g/mL for directly detecting lead in many of these samples. The linear dynamic range was higher than 2 orders of magnitude. A single sample analysis could be completed within 2 min with reasonable semi-quantitative performance, e.g., relative standard deviations (RSDs) for deionized water were 4.6-7.6% during 5 experimental runs (each of them had 10 repeated measurements). Coca-cola and Huiyuan orange juice, representative beverage samples with complex matrices, generated recovery rates of 91.5% and 129%, respectively. Our experimental data demonstrated that EESI-MS is a useful tool for the fast detection of lead in various solutions, and EESI-MS showed promises for fast screening of lead-contaminated aqueous liquid samples.

Microwave plasma torch mass spectrometry for the direct detection of copper and molybdenum ions in aqueous liquids

“…the fragment at m/z 143 of [ 63 Cu(NO 3 )∙2H 2 O] + for copper and m/z 162 of [ 98 MoO 3 (NO 3 )] − for molybdenum, respectively. Some previous studies have shown that the quantitative performance of MS n is better than that of the primary MS because the MS 2 mass spectrum generally has better signal noise ratio. The plots of the measured MS 2 fragment intensities versus the concentrations showed a good linear relationship in water solutions with the linear correlation square coefficients 0.994 for copper and 0.965 for molybdenum, respectively, as shown in Fig.…”

Identification of complexes involving thallium(I) and thallium(III) with EDTA and DTPA ligands by electrospray ionization mass spectrometry

“…For this reason, the combination of separation (IC or CE) with ESI‐MS is an appropriate approach . In contrast to ICP‐MS, the ESI‐MS technique allows for simultaneous identification of unknown compounds in the sample or confirmation of the presence of known chemical moieties without appropriate standards, based on the obtained mass spectra . This is of great importance during speciation studies focused on metal cations which occur as metal‐organic ligand complexes.…”

The cation−anion interaction in ionic liquids studied by extractive electrospray ionization mass spectrometry

“…1 as previously reported. 24,25 Herein, the angle ␣ between the spray outlet and the heated capillary of the LTQ instrument was maintained at about 150°, which was equivalent to the angle between sample beam and the heated capillary of the LTQ instrument. The angle ␤ between the sample plume outlet and the electrospray beam was about 60°.…”