Cold Vapor Atomic Absorption CVAA

Cold vapor atomic absorption (CVAA) spectrophotometry for mercury analysis... 

As, Sb, and Au determined by instrumental neutron activation analysis (INAA). Hg determined by cold vapor atomic absorption (CVAA). nd = not determined. 

In comparing the outcomes of the Faroe Islands, Seychelles, and New Zealand studies, it is important to consider the relative analytical errors in the measurement of the biomarker of exposure among those studies. Unfortunately, the reporting of such data in those studies is inconsistent and incomplete. The Seychelles study analyzed only maternal hair. Several analytical methods were used for various purposes in that study, the dose-response analysis used hair Hg concentration determined by cold vapor atomic absorption (CVAA). Although determinations were carried out to compare CVAA results with those from a reference method (counts of exogenously apphed Hg) (Cemichiari et al. 

Measurement was by cold-vapor atomic absorption (CVAA), which is based on the reduction of ionic mercury to the elemental form by divalent tin. The resultant elemental mercury is swept by a gas stream through a quartz-windowed absorption cell which is placed in the beam of a mercury lamp of an atomic absorption spectrometer. Hatch and Ott (11) optimized this measurement system in their study of the mercury content of geological samples. Since their work, this method of mercury measurement has gained widespread popularity because of its sensitivity and relative simplicity. Two recent reviews which cover the Hatch and Ott technique and its subsequent modifications have appeared (17,18). 

Cold Vapor Atomic Absorption Spectrometry (CVAAS)... 

Detection limits are presented for 61 elements by ten analytical determinative methods FAAS flame atomic absorption spectrometry ETAAS electrothermal atomization atomic absorption spectrometry HGAAS hydride generation atomic absorption spectrometry including CVAAS cold vapor atomic absorption spectrometry for Hg ICPAES(PN) inductively coupled plasma atomic emission spectrometry utilizing a pneumatic nebulizer ICPAES(USN) inductively coupled plasma atomic emission spectrometry utilizing an ultrasonic nebulizer ICPMS inductively coupled plasma mass spectrometry Voltammetry TXRF total reflection X-ray fluorescence spectrometry INAA instrumental activation neutron analysis RNAA radiochemical separation neutron activation analysis also defined in list of acronyms. 

Diethyldithiocarbamate, pyrrolidin-1 -yldithioformate, and diphenylthiocarbazone (dithizone), as three mercury chelate forming reagents, were used for the preconcentration of ultratrace amounts of inorganic mercury and methyl mercury in silica Cig minicolumn as the solid sorbent. Sample FI online sorbent extraction was coupled with continuous cold vapor atomic absorption spectrometry (CVAAS) for detection. The results showed the superiority of the carbamate type reagents over the dithizone for the online formation and preconcentration of the corresponding mercury chelate. The detection limit was found to be 16 ng/L of mercury. The structures of these organic chelate modifiers are shown in Scheme 17. 

The method which has demonstrated to be most successful one for mercury determination within natural waters is that called cold vapor-atomic absorption spectroscopy (CVAAS), which can be used with a preconcentration step [337-339] or without it [340-342], In addition, the use of continuous-flow systems for Hg CV generation has also been reported [343-345]. 

By way of example. Figure 4.5 shows a schematic depiction of an MCFIA system for determination of mercury in fish by cold vapor atomic absorption spectrophotometry (CVAAS) [35]. Independently controlled solenoid valves were used for reagents and sample injection. First, V2 and V3 were switched on at the same time to mix an equal volume of sample or standard and reducing reagent. This volume was determined by the flow... 

CVAA An abbreviation for cold vapor atomic absorption. 

In order to validate the ASV method for mercury determination on BDD, a comparison with cold-vapor atomic absorption spectrometry (CVAAS) has also been carried out using a real sample (KCl impinger solution) obtained from the flue gas of a coal-... 

CSV cathodic stripping voltammetry CVAAS cold vapor generation atomic absorption spectrometry (specific for Hg) CVAFS cold vapor atomic fluorescence spectrometry... 

It means they can now detennine the vast majority of the environmentally significant elements/species by one technique. This capability is very attractive because it means they can typically analyze 5-10 times more samples per day, for a full suite of elements, compared to other approaches that use a combination of flame atomic absorption (FAA), GFAA, CVAA (cold vapor AA for Hg), and ICP-OES. This productivity improvement is exemplified in Table 19.2, which compares the productivity of a drinking water analysis for 12 primary contaminants using three different analytical scenarios. " ... 

---