L-Cysteine as a reducing and releasing agent for the determination of antimony and arsenic using flow injection hydride generation atomic absorption spectrometry—Part 2. Interference studies and the analysis of copper and steel

Abstract

A method was developed for the determination of antimony and arsenic in copper and steel using f l o w injection hydride generation atomic absorption spectrometry (FI-HGAAS) and L-cysteine as reducing and releasing agent. Tolerance limits (less than 10% interference) of at least 250 and 500 m g 1-1 were found for nickel and copper, respectively, in the presence of 1 % m/v L-cysteine, in the determination of antimony. For the determination of arsenic the corresponding tolerance limits were 200 mg 1-1 for nickel and more than 1000 m g 1-1 for copper. Only 100 m g 1-1 of copper could be tolerated when potassium iodide was used for reduction. Higher copper concentrations resulted in precipitation o f copper(1) iodide, which caused severe contamination of the conduits of the FI system. L-Cysteine is, therefore, recommended for FI-HGAAS because of its better performance for the determination of antimony and arsenic and because of the much lower acid concentrations required. Very good agreement with the certified values for antimony and arsenic i n copper and steel National Institute of Standard and Technology Standard Reference Materials was obtained, o n addition of L-cysteine, b y calibration with matrix-free standard solutions, using the bracketing technique.

Investigation of the automated determination of As, Sb and Bi by flow-injection hydride generation using in-situ trapping on stable coatings in graphite furnace atomic absorption spectrometry

“…for As [18,20,22], for Sb [17,18,22], and for Bi [1], with 1% L-cysteine added in this work. L-cysteine was preferred because of the reasons given in the introduction and the tested conditions are summarized in Table 1.…”

“…The addition of L-cysteine to the sample solutions permits full recovery of the As signals [16,18,19] and of the Sb response [18,19] in presence of transition metals which interfere in the hydride generation step. In the presence of L-cysteine the pentavalent states of As and Sb are reduced and the trivalent state stabilized [18][19][20][21][22], thus making a separate reducing step obsolete. As and Sb hydride production by flow-injection in presence of 1% L-cysteine reached optimum conditions at low acid concentrations, i.e.…”

Determination of As, Hg and Pb in herbs using slurry sampling flow injection chemical vapor generation inductively coupled plasma mass spectrometry

“…Furthermore, the masking agent used might also improve 1.0% m/v Flow rate of solutions 0.80 mL min À1 Length of mixing coil 1 10 cm Length of mixing coil 2 10 cm the hydride generation efficiency of some elements. In this work, citric acid (Chen, Zhu, & Wu, 1994), L-cysteine (Chen, Brindle, & Le, 1992;Welz & Sucmanová, 1993), tartaric acid (Chen & Jiang, 2009b) and oxalic acid (Chen & Jiang, 2009b) were tested as masking agents to improve signals of As, Hg and Pb. From the experiments it was found that the addition of 1% m/v citric acid improved the ion signals of As and Hg and hence citric acid was selected as masking agent in this study.…”

Developments in the Determination of Trace Elements by Atomic Spectroscopic Techniques

“…It is virtually nontoxic, fully effective even in acid concentrations up to 1 mol L 21 , and its solutions are stable for several weeks. Welz and Sucmanova (1993) believe that L-cysteine acted by protecting Sb from the interference of copper species deposited on the tubing of the FIA system they used. On the other hand, showed that L-cysteine is completely ineffective if stibine is electrochemically generated.…”