[Crosslinked carboxymethyl konjac glucomannan microcolumn preconcentration of trace lead, cadmium and copper in water samples and determination by graphite furnace atomic absorption spectrometry].

A novel solid phase extraction technique was developed for the determination of trace lead, cadmium and copper in environmental water samples based on separation and preconcentration with a microcolumn packed with crosslinked carboxymethyl konjac glucomannan (CCMKGM)prior to its determination by graphite furnace atomic absorption spectrometry. Various influential factors on the separation and preconcentration of lead, cadmium and copper, such as the acidity of the aqueous solution, sample flow rate and volume, and eluent concentration and volume, were investigated systematically, and the optimized operation conditions were established. The analytes could be quantitatively retained by CCMKGM in the pH range of 5.0-7.0, then eluted completely with 1.0 mL 0.5 mol x L(-1) HCl. The detection limits (3sigma) for analyte ions were 0.038 microg x L(-1) for Pb2+, 0.0005 microg x L(-1) for Cd2+ and 0.014 microg x L(-1) for Cu2+ with an enrichment factor of 50, and the relative standard deviations were 3.5% for Pb2+, 9.2% for Cd2+ and 4.7% for Cu2+ (c(Pb2+) = C(Cu2+) = 1.0 microg x L(-1); c(Cd2+) = 0.1 microg x L(-1), n=11). The proposed method was successfully applied to the determination of trace lead, cadmium and copper in environmental water samples (local tap water and lake water). In order to validate the method, the developed method was applied to the determination of lead, cadmium and copper in environmental water reference materials (ERMs, GSBZ 50009-88, PR China), and the results obtained were in good agreement with the certified values.

[Determination of lead and cadmium in rapeseed and rapeseed meal with microwave digestion by graphite furnace atomic absorption spectrometry].

Comprehensive utilization of rapeseed and rapeseed meal has been increasingly emphasized, and contaminative problems of heavy metal have been attracting great attention, so it is of quite important significance to determine the contents of Pb and Cd. An effective method was developed for the rapid determination of Pb and Cd in rapeseed and rapeseed meal. Digestive dissolvent, time and pressure were discussed for sample preparation by microwave digestion technique, and the optimum condition of determination by GFAAS was studied. The determination limits were 2.172 and 0.243 microg x L(-1), and the linear arranges were 0-100 microg x L(-1) and 0-8 microg x L(-1) for Pb and Cd, respectively. The recoveries were from 80.8% to 110.7%. The RSD of determination was lower than 5.3%. The method offers traits of low detection limit, high sensitivity, speediness and exactness, and was applied to the determination of Pb and Cd in samples with satisfactory results.

[Preconcentration with crosslinked chitosan for determination of trace manganese in waters by flame atomic absorption spectrometry].

A novel method for the preconcentration with crosslinked chitosan (CCTS) and determination of trace manganese in waters by flame atomic absorption spectrometry has been presented. The absorption rate of manganese (VII) by CCTS was 98% at pH 3.00. The effect of preconcentration time, dosage of CCTS, temperature, sample volume and co-existing elements have been investigated. The mechanism of adsorption of CCTS for Mn(VII) was also discussed. The detection limit of the method was 1.86 microg x L(-1), and the relative standard deviation (RSD) was 2.0% (n = 10). The method has been applied to the determination of trace manganese in south lake and Changjiang water with satisfactory results.