Hydride generation atomic absorption spectrometry HG-AAS

Maintaining the quality of food is a far more complex problem than the quality assurance of non-food products. Analytical methods are an indispensable monitoring tool for controlling levels of substances essential for health and also of toxic substances, including heavy metals. The usual techniques for detecting elements in food are flame atomic absorption spectroscopy (FAAS), graphite furnace atomic absorption spectrometry (GF AAS), hydride generation atomic absorption spectrometry (HG AAS), cold vapour atomic absorption spectrometry (CV AAS), inductively coupled plasma atomic emission spectrometry (ICP AES), inductively coupled plasma mass spectrometry (ICP MS) and neutron activation analysis (NAA). 

Hydride Generation Atomic Absorption Spectrometry HG AAS is a method that makes use of the ability of such elements as As, Bi, Ge, Pb, Sb, Se, Sn and Te to form volatile compounds with hydrogen. 

Anthemidis, A. N., E. I. Daftsis, and N. O. Kalogiouri. 2014. A sequential lab-on-valve (SIA-LOV) platform for hydride generation atomic absorption spectrometry (HG-AAS) On-line determination of inorganic arsenic. Anal. Methods 6 2745-2750. 

HG hydride generation HG-AAS hydride generation atomic absorption spectrometry HG-AES hydride generation -atomic emission spectrometry... 

Samanta G, Chakraborti D. 1996. Flow injection hydride generation atomic absorption spectrometry (FI-HG-AAS) and spectrophotometric methods for determination of lead in environmental samples. Environmental Technology 17(12) 1327-1337. 

Boron, Li, Mo, Pb, and Sb were determined in the standard mode, while Al, Cd, Co, Ni, Mn, Rb, Sb, Sn, and V were determined in the DRC mode. The determination of Ni was done with a gas flow of 0.15 ml min-1 of CH4, while for the other elements NH3 was used as cell gas at 0.4 ml min-1. The determination of Se by flow injection hydride generation atomic absorption spectrometry (FI-HG-AAS) was carried out by means of the Perkin-Elmer FLAS 200 system, equipped with the Perkin-Elmer autosampler AS-90, and connected to an electrically heated quartz cell installed on a PerkinElmer absorption spectrometer AAS 4100. The analytical conditions are given in Table 10.3. 

ETA-AAS, Electrothermal Atomization Atomic Absorption Spectrometry FAAS, Flame Atomic Absorption Spectrometry HG-AAS, Hydride Generation Atomic Absorption Spectrometry ICP-AES, Inductively Coupled Plasma Atomic Emission Spectrometry ID-MS, Isotopic Dilution Mass Spectrometry NAA, Neutron Activation Analysis Q-ICP-MS, Quadrupole Inductively Coupled Plasma Mass Spectrometry SS-Z-ETA-AAS, Solid Sampling Zeeman Atomic Absorption Spectrometry Z-ETA-AAS, Zeeman Electrothermal Atomization Atomic Absorption Spectrometry... 

Quartz tube (QT) atomisation and high-resolution continuum source hydride generation atomic absorption spectrometry (FIR-CS HG-AAS) were used to determine lead. A full two-level factorial design characterised the effects of the reagent concentrations. The experimental conditions were determined using a Box-Behnken design. 

Total dissolved Fe and Mn were analyzed directly by flame atomic absorption spectrometry (AAS). As was measured by AAS with hydride generation (HG-FIAS). Total dissolved Se concentrations were determined by hydride-generation atomic fluorescence spectrometry (Chen etal., 2005). 

The most suitable techniques for the rapid, accurate determination of the elemental content of foods are based on analytical atomic spectrometry, for example, atomic absorption spectrometry (AAS), atomic emission spectrometry (AES), and mass spectrometry, the most popular modes of which are Game (F), electrothermal atomization (ET), and hydride generation (HG) AAS, inductively coupled plasma (ICP), microwave-induced plasma (MIP), direct current plasma (DCP) AES, and ICP-MS. Challenges in the determination of elements in food include a wide range of concentrations, ranging from ng/g to percent levels, in an almost endless combination of analytes with matrix speci be matrices. 

Early colorimetric methods for arsenic analysis used the reaction of arsine gas with either mercuric bromide captured on filter paper to produce a yellow-brown stain (Gutzeit method) or with silver diethyl dithiocarbamate (SDDC) to produce a red dye. The SDDC method is still widely used in developing countries. The molybdate blue spectrophotometric method that is widely used for phosphate determination can be used for As(V), but the correction for P interference is difficult. Methods based on atomic absorption spectrometry (AAS) linked to hydride generation (HG) or a graphite furnace (GF) have become widely used. Other sensitive and specihc arsenic detectors (e.g., AFS, ICP-MS, and ICP-AES) are becoming increasingly available. HG-AES, in particular, is now widely used for routine arsenic determinations because of its sensitivity, reliability, and relatively low capital cost. 

Technique HG = hydride generation AAS = atomic absorption spectrometry GF = graphite furnace AES = atomic emission spectrometry MS = mass spectrometry AFS = atomic fluorescence spectrometry ASV = anodic stripping voltammetry SDDC = sodium diethyl dithiocarbamate. Procedures ISO = Memational Standards Organization ISO/CD = ISO Committee Draft SM = Standard Methods ... 

Whatever the analytical method and the determinand may be, the greatest care should be devoted to the proper selection and use of internal standards, careful preparation of blanks and adequate calibration to avoid serious mistakes. Today the Antarctic investigator has access to a multitude of analytical techniques, the scope, detection power and robustness of which were simply unthinkable only two decades ago. For chemical elements they encompass Atomic Absorption Spectrometry (AAS) [with Flame (F) and Electrothermal Atomization (ETA) and Hydride or Cold Vapor (HG or CV) generation]. Atomic Emission Spectrometry (AES) [with Inductively Coupled Plasma (ICP), Spark (S), Flame (F) and Glow Discharge/Hollow Cathode (HC/GD) emission sources], Atomic Fluorescence Spectrometry (AFS) [with HC/GD, Electrodeless Discharge (ED) and Laser Excitation (LE) sources and with the possibility of resorting to the important Isotope... 

Atomic absorption spectrometry, belonging to a class of techniques also defined as optical atomic spectrometry, has been for some four decades - and continues to be - one of the most important, dominant determinative techniques. It includes flame atomic absorption spectrometry (FAAS), electrothermal atomization atomic absorption spectrometry (ETAAS) (including graphite furnace AAS (GFAAS), carbon rod AAS, tantalum strip AAS), and gaseous generation (cold vapor AAS for Hg, hydride gener-... 

Gas chromatography, GC mass spectrometry, MS hydride generation, HG atomic absorption spectrometry, AAS inductively coupled plasma, ICP solid phase microextraction, SPME fluorine-induced chemiluminescence, FIG. 

Figure 3 Instrumental methods for the determination of arsenic compounds (Abbreviations AAS, atomic absorption spectrometry APS, atomic fluorescence spectrometry CE, capillary electrophoresis GC, gas chromatography HG, hydride generation ICP-AES, inductively coupled plasma-atomic emission spectrometry ICP-MS, inductively coupled plasma-mass spectrometry INAA, instrumental neutron activation analysis LC, liquid chromatography MS, mass spectrometry).

Nowadays, atomic absorption spectrometry (AAS) systems are comparatively inexpensive element selective detectors, and some of the instruments also show multi(few)-element capability. There are flame (F AAS), cold vapor (CV AAS), hydride-generating (HG AAS), and graphite furnace (GF-AAS) systems. However, the use of AAS-based detectors for on-line speciation analysis is problematic. F AAS is usually not sensitive enough for speciation analysis at "normal" environmental or physiological concentrations and sample intake is high (4—5 ml/min), which complicates on-line hyphenations with LC an auxiliary flow is necessary. CV AAS and HG AAS use selective derivatization for matrix separation and increased sensitivity for the derivatized species. But, the detector response is species dependent and interferences can be a problem. GF AAS requires only a few microliters of sample and provides low detection limits, between 0.1 and 5 gg/1. Matrix interferences are widely eliminated by Zeeman correction and matrix modifiers nevertheless, quantification errors were reported as atomization temperature does not exceed 2900°C. The most critical problem in respect to speciation analysis is the discontinuous measiuement because of the temperature program operation employed, which takes a few minutes. Therefore, GF AAS is unsuitable for on-line hyphenations as chromatograms carmot be monitored with sufficient resolution. 

Arsenic species that have been identified in the terrestrial environment are listed in Table 3. Apart from the inorganic species, which predominate in all environmental compartments, they are mainly methylarsenicals and are presumably formed via the same biological process outlined above. The formulations given for the methylarsenic(III) species are probably not correct because compounds of this type are unknown. It is likely that the species are actually thiols CH3As(SR)2 and (CH3)2AsSR (19). The reason for the uncertainty is that the analytical technique commonly used to determine arsenic species is hydride generation (HG) followed by some form of separation and detection, e.g, gas chromatography (GC) and atomic absorption (AA) spectrometry hence HG/GC/AA. 

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