The analytical performances of coupled chemical vapor generation, integrated atom trap (CVG-IAT) atomizer flame atomic absorption spectrometry (FAAS) system were evaluated for determination of nickel in environmental samples. Nickel chemical vapors are atomized in an air-acetylene flame-heated IAT. A new design of CVG-IAT-FAAS hyphenated technique that would exceed the operational capabilities of existing arrangements (a water-cooled single silica tube, double-slotted quartz tube) permitting construction of an “integrated trap” was investigated. An improvement in limit of detection was achieved compared with that obtained using any of the above atom trapping techniques separately. The concentration limit of detection was 1 ng mL−1 for Ni. The overall efficiencies of the vapor generation process was estimated to be ca. 50%. For a 2 min in situ pre-concentration time, sensitivity enhancement, compared to FAAS, was 200 folds for Ni, using vapor generation atom trapping technique. The sensitivity can be further improved by increasing the collection time. The precision of the measurements for 25 ng mL−1 of Ni was 9% RSD. The accuracy of this method was tested by analyses of NIST SRM 2704 (Buffalo River Sediment), NIST SRM 1648 (Urban Particulate Matter), NIST SRM 2710 (Montana Soil), NBS SRM 1633a (Coal Fly Ash) and NIST SRM 1643e (Trace Element in Water) certified reference materials. The measured Ni content in five reference materials was in satisfactory agreement with the certified values (in the range of 14.3–98 μg g−1). The hyphenated technique was applied for nickel determination in coal fly ash, soil, sediment, sewage and river water. [...]
Sample preparation methods for non-separation cold vapor atomic absorption spectrometry (CVAAS) sequential inorganic mercury speciation in biological certified reference materials (CRMs) were investigated. The methylmercury concentration was calculated as the difference between total and inorganic mercury. Microwave-assisted decomposition method, and three ultrasonic extraction procedures based on acid leaching with HCl and HCOOH and solubilization with TMAH were employed as sample preparation methods. The replacement of a sample decomposition procedure by extraction prior to analysis by CVAAS, as well as the aspect of speciation analysis is discussed. The limits of detection in the sample were determined as 50 and 10 ng L−1 for inorganic and total mercury, which corresponds to absolute detection limits of 40 and 8 ng g−1 for inorganic and total mercury, respectively. The results were in good agreement with the 95% confidence level t-test of the certified values for total and inorganic mercury in the reference materials investigated. From the analysis of the CRMs, it was evident that the difference between the total and inorganic mercury concentrations agrees with the methylmercury concentration. The relative standard deviation was better than 11% for most of the samples. [...]
A microchip-based capillary electrophoresis (µCE) system was interfaced with a microwave induced plasma optical emission spectrometry (MIP-OES) to provide copper species separation capabilities. This system uses an extremely low flow demountable direct injection high efficiency nebulizer (D-DIHEN) sited directly at the liquid exit of the chip. A supplementary flow of buffer solution at the channel exit was used to improve nebulization efficiency. A small evaporation chamber has been incorporated into the interface in order to prevent the losses associated with traditional spray chambers, allowing the entire aerosol sample to enter the plasma. Syringe pumps were used to manipulate the flow rate and flow direction of the sample, buffer, and supplementary buffer solution. Sample volumes of 25 nL can be analyzed. With application of an electric field up to 500 V cm−1, species such as Cu(II) and Cu(EDTA)2− were separated in acidic solution within 90 s using a 26 mm long separation channel etched in a glass base. Resolution of the Cu(II) and Cu(EDTA)2− peaks was 1.1 using the chip-based µCE-MIP-OES system. [...]
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