Electrochemical atomic absorption spectrometry

In the determination of lead in aqueous solution by electrochemical atomic-absorption spectrometry with graphite-probe atomization, the following results were obtained ... 

FLOW INJECTION ELECTROCHEMICAL HYDRIDE GENERATION ATOMIC ABSORPTION SPECTROMETRY EOR THE DETERMINATION OE ARSENIC... 

In contrast, the coupling of electrochemical and spectroscopic techniques, e.g., electrodeposition of a metal followed by detection by atomic absorption spectrometry, has received limited attention. Wire filaments, graphite rods, pyrolytic graphite tubes, and hanging drop mercury electrodes have been tested [383-394] for electrochemical preconcentration of the analyte to be determined by atomic absorption spectroscopy. However, these ex situ preconcentration methods are often characterised by unavoidable irreproducibility, contaminations arising from handling of the support, and detection limits unsuitable for lead detection at sub-ppb levels. 

Analytical Techniques Atomic absorption spectrometry, 158, 117 multielement atomic absorption methods of analysis, 158, 145 ion microscopy in biology and medicine, 158, 157 flame atomic emission spectrometry, 158, 180 inductively coupled plasma-emission spectrometry, 158, 190 inductively coupled plasma-mass spectrometry, 158, 205 atomic fluorescence spectrometry, 158, 222 electrochemical methods of analysis, 158, 243 neutron activation analysis, 158, 267. 

M. H. Arbab-Zavar, M. Chamsaz, A. Youssefi and M. Aliakbari, Electrochemical hydride generation atomic absorption spectrometry for determination of cadmium. Anal. Chim. Acta, 546(1), 2005, 126-132. 

Various spectroscopic techniques such as flame photometry, emission spectroscopy, atomic absorption spectrometry, spectrophotometry, flu-orimetry, X-ray fluorescence spectrometry, neutron activation analysis and isotope dilution mass spectrometry have been used for marine analysis of elemental and inorganic components [2]. Polarography, anodic stripping voltammetry and other electrochemical techniques are also useful for the determination of Cd, Cu, Mn, Pb, Zn, etc. in seawater. Electrochemical techniques sometimes provide information on the chemical species in solution. 

Li, X., Jia, J., Wang, Z. Speciation of inorganic arsenic by electrochemical hydride generation atomic absorption spectrometry. Anal. Chim. Acta 560, 153-158 (2006)... 

The very low concentrations expected in the analysis of trace elements in offshore and coastal Antarctic sea water can be also detected thanks to the high detection power of spectroscopic techniques such as Electrothermal Atomic Absorption Spectrometry (ETA-AAS) and Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES) or ICP-MS. However, the saline matrix which constitutes the ideal medium in which to perform electrochemical measurements poses severe problems to the direct analysis of sea water because of possible signal suppression and/or undesired matrix effects. 

Liu Y., Wang X., Yuan D., Yang P., Huang B. and Zhuang Z. (1992) Flow-injection-electrochemical hydride generation technique for atomic absorption spectrometry, J Anal At Spectrom 7 287-291. 

Indirect detection is possible with all selective detection principles, e.g. with fluorescence detection (if the mobile phase itself is fluorescent) or electrochemical detection (if the mobile phase can act as an electrochemical reaction partner). Even indirect detection with atomic absorption spectrometry has been described, the mobile phase containing lithium or copper and the spectrometer being used with a lithium or copper lamp. ... 

The range of off-line instruments available for water analysis Is wide. In fact, any analyser with optical or electrochemical detection can be adapted for this purpose. The use of liquid chromatography for the detection and quantitation of detergents or non-volatile organic compounds, of atomic absorption spectrometry for the analysis for heavy metal traces and of UV spectrophotometry for the determination of phosphates, nitrates and nitrites are representative examples of the potential utilization of conventional analysers for water analysis. 

Methods for quantitative analysis of Co indude flame and graphite-furnace atomic absorption spectrometry (AAS e.g., Welz and Sperling 1999), inductively coupled plasma emission spectrometry (ICP-AES e.g., Schramel 1994), neutron activation analysis (NAA e.g., Versieck etal. 1978), ion chromatography (e.g., Haerdi 1989), and electrochemical methods such as adsorption differential pulse voltammetry (ADPV e.g., Ostapczuk etal. 1983, Wang 1994). Older photometric methods are described in the literature (e.g.. Burger 1973). For a comparative study of the most commonly employed methods in the analysis of biological materials, see Miller-Ihli and Wolf (1986) and Angerer and Schaller... 

Keywords Trace elements Radionuclides Environment Water Soil Aerosol Plant Neutron activation analysis Atomic absorption spectrometry Inductively coupled plasma-atomic emission spectroscopy Inductively coupled plasma-mass spectrometry X-ray fluorescence Electrochemical methods Speciation... 

In order to evaluate possible hazards for the enviroiunent and human health it is crucial to develop analytical strategies for fast and easy quantification of traces and ultra-traces of Pd in environmental matrices as well as biological tissues and fluids. Despite the efforts of numerous workgroups, a reliable method for the determination of Pd in all environmental matrices has yet to be developed. Up to date, the most important analytical methods for this task are electrothermal atomic absorption spectrometry (ETAAS), inductively coupled plasma-mass spectrometry (ICP-MS) and isotope dilution (ID)-ICP-MS, also strategies involving inductively coupled plasma-atomic emission spectrometry (ICP-AES), and electrochemical methods like anodic stripping voltammetry (ASV) have been described. Furthermore, total reflection X-ray fluorescence (TXRF) and instrumental neutron activation analysis (INAA) have been successfully employed for the determination of PGE in enviromnental matrices. 

Any of the methods of detection used in liquid chromatography can be used in IC, though some are more useful than others. If the eluent does not affect the detector the need for a suppressor disappears. Common means of detection in IC are ultraviolet (UV) absorption, including indirect absorption electrochemical, especially amperometric and pulsed amperometric and postcolumn derivatization. Detectors atomic absorption spectrometry, chemiluminescence, fluorescence, atomic spectroscopic, refractive index, electrochemical (besides conductivity) including amperometric, coulometric, potentiometric, polaro-graphic, pulsed amperometric, inductively coupled plasma emission spectrometry, ion-selective electrode, inductively coupled plasma mass spectrometry, bulk acoustic wave sensor, and evaporative light-scattering detection. 

Different techniques are in use for analysis of the filtration fraction and concentrates. Most often multielement techniques such as ICP AES/MS and X-ray fluorescence (XRF) spectrometry are applied. Use of electrochemical methods and different techniques of atomic absorption spectrometry (AAS) is also possible. 

Detection methods applied in ion chromatography (IC) can be divided into electrochemical and spectrometric methods. Electrochemical detection methods include conductometric, amperometric, and potentiometric methods, while spectroscopic methods include molecular techniques (UVA is, chemiluminescence, fluorescence, and refractive index methods), and spectroscopic techniques such as atomic absorption spectrometry (AAS), atomic emission spectrometry (AES), inductively coupled plasma-optical emission spectrometry (ICP-OES), inductively coupled plasma-mass spectrometry (ICP-MS), and mass spectrometry (MS). ... 

The earliest methods for tin analysis, namely, gravimetric and titrimetric methods, are now mainly of historical interest. Being essentially macro methods, laborious in application, they are limited and mainly useful for levels of tin in food in the 50-100 ppm range or above. The use of colorimetric analysis is associated with problems of specificity, sensitivity, and stability of the tin complexes formed. Nowadays, methods for tin analysis in biological media include the various atomic spectroscopic techniques (atomic absorption spectrometry, atomic emission spectroscopy, and inductively coupled plasma atomic emission spectrometry) as well as electrochemical and neutron activation procedures. 

The definitive method for Pb quantification in biological media, and notably whole blood, is IDMS. IDMS accuracy traces to the fact all analytical manipulations are on a weight basis and entail simple procedures (NAS/NRC, 1993 U.S. EPA, 1986). There are essentially two reference methods, both validated with IDMS and in widespread use for routine measurements in environmental and occupational epidemiology and clinical applications (NAS/NRC, 1993 U.S. EPA, 2006). These are a spectroscopic method, graphite-furnace atomic absorption spectrometry (GE-AAS), and an electrochemical approach, ASV. Both ASV and GE-AAS demonstrate the requisite track record in terms of accuracy, precision, time requirements, and cost-effectiveness for routine but reliable methodology (Flegal and Smith, 1995 NAS/NRC, 1993). ICP-MS can also be viewed as a reference method for those analytical settings where costs for operator expertise, instrumentation, and procedures are not critical, such as academic research laboratories. 

Routine analytical methods typically include micro (graphite furnace) atomic absorption spectrometry and electrochemical approaches such as anodic-stripping voltammetry. More complex, expensive and nonroutine/ research approaches are inductively coupled plasma-mass spectrometry and definitive methods such as thermal ionization-mass spectrometry. These methods have the requisite sensitivity, specificity, and record of reliability for quantification across the range of environmental exposures that humans presently encounter. Combining current instrumental methods with carefiil quality assurance and quality control protocols permits adequate proficiency for even low Pb concentrations, values of 1—2 pg/dl. 

B. Godlewska-Zylkiewicz and M. Zaleska. Preconcentration of palladium in a flow-through electrochemical cell for determination by graphite furnace atomic absorption spectrometry. Analytica Chimica Acta 462 305-312, 2002. 

J. Knapek, J. Komarek, and P. Krasensky. Determination of cadmium by electrothermal atomic absorption spectrometry using electrochemical separation in a microcell. Spectrochimica Acta Part B 60 393-398, 2005. 

R.G.M. Moreno, E. de Oliveira, J.J. Pedrotti, and P.V. Oliveira. An electrochemical flow-cell for permanent modification of graphite tube with palladium for mercury determination by electrothermal atomic absorption spectrometry. Spectrochimica Acta Part B 57 769-778, 2002. 

Trace elements and minerals are essential in biological processes for human normal growth and development however, high concentrations, accumulation, or low intake may lead to deficiencies and/or diseases. Among the most important elements found in food, Cu, Fe, Mn, Zn, Co, and Se stand out. The conventional method to quantify trace metals in these samples is flame atomic absorption spectrometry. Table 2.3 shows some recent literature regarding quantification of trace elements and minerals by electrochemical techniques in food samples. 

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