On-line matrix removal of lead for the determination of trace elements in forensic bullet samples by flow injection inductively coupled plasma-mass spectrometry

Abstract

The determination of trace elements in lead by inductively coupled plasma ICP Ž.source mass spectrometry ŽMS is . not possible without the removal of a substantial proportion of the lead matrix. This was achieved by the retention of lead from a 130-l sample solution Ž100 mg l y1 lead in 2% vrv nitric acid injected into a single-line .Ž3% vrv nitric acid. flow injection manifold, on 100 mg of Pb-Spec ᮋ packed into a cylindrical column Ž6 cm =4 mm internal diameter.. The analytes, Ag, As, Bi, Cd, Cu, Sb and Sn, passed through the column and were quantified against matrix-matched standards. Only Ag showed significant retention, but could still be measured in an 8-min run. The column was rinsed by flushing with 0.1 M ammonium citrate solution. Lead was monitored by flame atomic absorption spectrometry in preliminary experiments concerning column capacity and breakthrough. Although the capacity of the material in the dynamic, flow-through mode was less than the literature value based on equilibrium studies, the lead from up to 13 successive injections was sufficiently retained to allow accurate determination of the analytes without intermediate rinsing of the column. The precision wpercentage relative standard deviation %R.S.D.Ž., ns5x of the procedure ranged from 1.7% Ž100 ng ml y1 copper to 2.8% .Ž5 ng ml y1 cadmium., and detection limits were in the range 0.2᎐10 ng ml y1 . The accuracy of the procedure was assessed by the analysis of three National Institute of Standards and Technology standard reference materials ŽSRM 2416 bullet lead, SRM 2415 battery lead, and SRM 2417 lead base alloy.. For each SRM, duplicate determinations of seven analytes were made. Of the 42 determinations, 36 fell within the confidence interval around the accepted value. Three real bullets were analyzed for seven elements by both the flow injection solid-phase extraction ICP-MS method and by aspiration of the bullet solutions Ž10 000 mg l y1 lead. directly into an ICP emission spectrometer. A linear least squares regression of these U Corresponding author. two sets of results gave a line with slope 1.01"0.04 and an intercept of y5"100 gg y1 , where the " terms are 95% confidence intervals. The column lifetime was in excess of 5 months of daily use.

Evaluation of Pb-Spec® for flow-injection solid-phase extraction preconcentration for the determination of trace lead in water and wine by flame atomic absorption spectrometry

“…As it has been reported [17,19,21,22] that the sorption characteristics of the resin for lead are affected by the concentration of nitric acid, the concentration of nitric acid in the carrier solution was varied over a range. This range was 0-20% (v/v) for manifold 1, and 0-5% (v/v) for manifold 2.…”

“…This characteristic of the resin has proven advantageous for the determination of trace lead in iron and steel [18], and the resin's high capacity for lead has been exploited for matrix removal for multielement determinations [19]. Recently, the procedure used for the analysis of iron and steel has been adapted [20] for the preconcentration and determination of lead in river and seawater materials by FI-FAAS and FI-ICP-MS.…”

Preparation of nano-sized Pb2+ imprinted polymer and its application as the chemical interface of an electrochemical sensor for toxic lead determination in different real samples

“…Great efforts have been made to analyze lead in trace levels by means of a wide range of spectrometric methods such as electrothermal atomization atomic absorption spectrometry (ET-AAS), sequential multi-element flame atomic absorption spectrometry, graphite furnace atomic absorption spectrometry (GFAAS), electrothermal atomic absorption spectrometry, inductively coupled plasma-mass spectrometry (ICP-MS), hydride generation atomic absorption spectrometry and flame atomic absorption spectrometry (FAAS) [7][8][9][10][11][12][13][14][15].…”

Comparison of supported liquid membranes and solid-phase extraction for quantitative removal of lead from aqueous solutions

“…In developing a method for the analysis of bullets by ICP-MS, we initially chose FI-SPE to remove the lead (4). Most of the previous work on the use of solid-phase reactors in FI systems for the separation of analytes from matrices has been based on a protocol whose primary goal is preconcentration.…”

“…The SPE manifold, which provides the basis for the comparison, has been described previously (4). To summarize, a 130 µL sample was injected into a nitric acid carrier that moved the sample through a glass column (5 cm × 4 mm i.d.)…”