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In this work, a rapid method for discrimination between trace amounts of ionic silver and silver nanoparticles (AgNPs) using graphite furnace atomic absorption spectrometry (GFAAS) was developed. Systematic studies of the influence of stabilizing agents (Triton X-100, Tween 80, sodium dodecyl sulfate, tetrabutylammonium hydroxide (TBAH), tetramethylammonium hydroxide (TMAH), gelatine, and sodium citrate) on the determination of Ag+ and AgNPs of diameter 10–100 nm were undertaken. Careful optimization of atomization conditions (wall or platform atomization, heating rate, atomization temperature) was also completed. The atomization delay time (tad) was used to compare the atomization profiles of different silver species. The best resolution of signals was obtained for silver atomization from the graphite platform at 975 °C using 2 × 10−3 mol L−1 of sodium citrate as a stabilizer. The linear relationship between tad and AgNP size was applied to estimate NP diameter. The within-day repeatability of the method was 1.1–2.3% for 2.5 μg L−1 of AgNPs. The accuracy of the method was shown by the analysis of the reference material of AgNPs (RM 8017). To evaluate the utility of the proposed method for simultaneous qualitative and quantitative determination of silver forms, the analysis of model mixtures containing Ag+ and AgNPs of different sizes was done. The benefits and restrictions of the developed method are discussed in this context. Finally, the method was used for assessment of silver migration from fabrics and hygiene products. [ABSTRACT FROM AUTHOR]

Magnetic particles covered with functionalized silver nanoparticles are used in a micro-solid phase extraction procedure for the separation and preconcentration of mercury compounds. Functionalization with the sodium salt of 2-mercaptoethane-sulphonate (MESNa) allows Hg(ii) ions to be adsorbed. When MESNa is replaced by l-cysteine, monomethyl mercury, dimethyl mercury, ethyl mercury, phenyl mercury and diphenyl mercury are also retained. After separation by means of a magnetic field, the analytes are released from the nanocomposites by treating with a small volume of a potassium iodide solution. Mercury is then measured by electrothermal atomic absorption spectrometry using silver nitrate and potassium permanganate solutions for chemical modification. The preconcentration factor is close to 200, and a detection limit of 0.01 μg L−1 mercury is achieved. The results for total mercury are verified using certified reference materials. Water and edible fish oils are analyzed for total mercury and for two fractions or mercury organic compounds with the help of a solid phase extraction cartridge. [ABSTRACT FROM AUTHOR]

The presence of a low amount of silver nanoparticles (AgNPs) in a medium containing ammonium pyrrolidine dithiocarbamate (APDC) and cadmium ions facilitates the cloud point extraction of the Cd–APDC complex by Triton X-114. The metallic ion is completely transferred to the surfactant-rich phase and then measured by electrothermal atomic absorption spectrometry. Using a 20 mL aqueous sample containing 100 μg L−1 AgNPs and 0.075% (w/v) Triton X-114, the enrichment factor of the cadmium complex is found to be 1050, which results in a detection limit of 1 ng L−1. The procedure shows good selectivity and reproducibility close to 5%, and its reliability is verified by analyzing three water samples with a certified cadmium content. Results for other water samples as well as for beer and wine samples are also given. [ABSTRACT FROM AUTHOR]