Simultaneous Determination of As, Bi, Sb, Se, Te, Hg, Pb and Sn by Small-Sized Electrothermal Vaporization Capacitively Coupled Plasma Microtorch Optical Emission Spectrometry Using Direct Liquid Microsampling.

Simion Bogdan Angyus,Radu Etz,Tiberiu Frentiu,Erika Levei,Dorin Petreus,Michaela Ponta,Oana Teodora Moldovan,Eniko Covaci,Eugen Darvasi

doi:10.3390/molecules26092642

Abstract

The simultaneous determination of chemical vapor-generating elements involving derivatization is difficult even by inductively coupled plasma optical emission spectrometry or mass spectrometry. This study proposes a new direct liquid microsampling method for the simultaneous determination of As, Bi, Se, Te, Hg, Pb, and Sn, using a fully miniaturized set-up based on electrothermal vaporization capacitively coupled plasma microtorch optical emission spectrometry. The method is cost-effective, free from non-spectral interference, and easy to run by avoiding derivatization. The method involves the vaporization of analytes from the 10 µL sample and recording of episodic spectra generated in low-power (15 W) and low-Ar consumption (150 mL min−1) plasma microtorch interfaced with low-resolution microspectrometers. Selective vaporization at 1300 °C ensured the avoidance of non-spectral effects and allowed the use of external calibration. Several spectral lines for each element even in the range 180–210 nm could be selected. Generally, this spectral range is examined with large-scale instrumentation. Even in the absence of derivatization, the obtained detection limits were low (0.02–0.75 mg kg−1) and allowed analysis of environmental samples, such as cave and river sediments. The recovery was in the range of 86–116%, and the accuracy was better than 10%. The method is of general interest and could be implemented on any miniaturized or classical laboratory spectrometric instrumentation.

Highlights

The increasing interest in the determination of As, Bi, Sb, Se, Te, Hg, Pb, and Sn is closely related to their special uses in emerging technologies for the synthesis of materials or medicine [1,2,3,4]
As well as the high toxicity of Pb, Hg, As, and Sb are well known [7,8,9,10]. The quantification of these elements in environmental and biological samples, food, and materials by spectrometric methods is not an easy task given the low sensitivity of the spectral lines, spectral and non-spectral interferences even in the case of high-performance techniques such as graphite or quartz furnace atomic absorption spectrometry (GFAAS, QFAAS), atomic fluorescence spectrometry (AFS), and inductively coupled plasma optical emission or mass spectrometry (ICP OES, ICP-MS)
The classical hydride generation (HG)/cold vapor (CV) generation using NaBH4 and SnCl2 [11,12,13] combined with spectrometric methods are the most common approaches. Such examples are HG-AFS and CV-AFS [14,15,16,17,18,19], HG coupled with high-resolution continuum source electrothermal atomic absorption spectrometry or quartz furnace atomic absorption spectrometry (HG-HR-CS-ETAAS, HG-HR-CS-QFAAS) [20,21,22] and graphite furnace atomic absorption spectrometry (HG-GFAAS) [23]

Summary

Introduction

The increasing interest in the determination of As, Bi, Sb, Se, Te, Hg, Pb, and Sn is closely related to their special uses in emerging technologies for the synthesis of materials or medicine [1,2,3,4]. As well as the high toxicity of Pb, Hg, As, and Sb are well known [7,8,9,10] The quantification of these elements in environmental and biological samples, food, and materials by spectrometric methods is not an easy task given the low sensitivity of the spectral lines, spectral and non-spectral interferences even in the case of high-performance techniques such as graphite or quartz furnace atomic absorption spectrometry (GFAAS, QFAAS), atomic fluorescence spectrometry (AFS), and inductively coupled plasma optical emission or mass spectrometry (ICP OES, ICP-MS). The concept of ETV miniaturized systems using a platform or metal coil for sample introduction in liquid or solid form was successfully implemented for the quantification of elements generating chemical vapor without derivatization by ETV-AFS [49], ETV-ICP OES, and ETV-ICP-MS [50,51,52,53,54]. Karanassios’ group developed miniature ETV devices with metallic filaments that were further considered by other researches as a universal and easy approach for the introduction of liquid sample in microplasmas, widening the applicability

Objectives

Methods

Conclusion