Determination of thallium traces by ETAAS after on-line matrix separation and preconcentration in a flow injection system

Abstract

Um sistema de injeção em fluxo sensível e simples foi desenvolvido para separação, pré-concentração e determinação de tálio. A pré-concentração é baseada na sorção do analito em uma microcoluna de dibenzo-18-coroa-6 (DB18C6) imobilizada em alumina revestida com surfactante e subseqüente eluição com solução de ácido nítrico (500 µL, 2 mol L -1 ). A concentração de tálio no eluente foi determinada por espectrometria de absorção atômica com atomização eletrotérmica. Os fatores que influenciaram a sorção e dessorção de íon tálio foram investigados. Para um volume da amostra de 5 mL, a calibração foi linear no intervalo de 0,1 a 20 µg L -1 (r = 0,9996) com um limite de detecção de 0,05 µg L -1 . A capacidade máxima de sorção foi de 1432 µg de tálio por grama do sorbente. A precisão do método para 1 µg L -1 foi 5,7% RSD (n = 11). O método foi aplicado para determinação de tálio em água, cabelo, unha e em materiais de referência certificados. A exatidão foi avaliada empregando experimentos de adição e recuperação ou por comparação dos resultados com materiais de referência certificados.A simple and sensitive flow injection system was developed for separation, preconcentration and determination of thallium. Preconcentration is based on the analyte sorption on a microcolumn of dibenzo-18-crown-6 (DB18C6) immobilized on surfactant coated alumina with subsequent elution using a nitric acid solution (500 µL, 2 mol L -1 ). The concentration of thallium in the eluent was determined using electrothermal atomic absorption spectrometry. Factors influencing the sorption and desorption of thallium ion were investigated. Using a sample volume of 5 mL, the calibration was linear from 0.1 to 20 µg L -1 range (r = 0.9996) with a detection limit of 0.05 µg L -1 . The maximum sorption capacity was 1432 µg of thallium per gram of sorbent. The precision of the method at 1 µg L -1 was 5.7% RSD (n = 11). The method was applied for determination of thallium in water, hair, nail, and standard reference samples. The accuracy was assessed using addition-recovery experiment or by comparison of the results with certified reference materials.

Presence of thallium in the environment: sources of contaminations, distribution and monitoring methods

“…The developed analytical procedure allowed for a 50-fold enrichment and determination of 0.05 μg L −1 of thallium in wine. The ETAAS method was also employed for determination of thallium in hair and nails (Asadoulahi et al 2007) as well as spring water with a detection limit of 0.08 μg L −1 (Stafilov and Cundeva 1998). …”

Solidified floating organic drop microextraction (SFODME) for simultaneous separation/preconcentration and determination of cobalt and nickel by graphite furnace atomic absorption spectrometry (GFAAS)

“…[5][6][7], have been used for determination of traces of metal ions in various media. However, in these determinations, low concentration levels of analytes and high levels of matrices are the main problems [8,9]. To solve these problems, a separation/preconcentration step prior to analysis is required.…”

A novel ionic liquid/micro-volume back extraction procedure combined with flame atomic absorption spectrometry for determination of trace nickel in samples of nutritional interest

“…The ore samples were prepared as described else where [34], i.e. proper amount of standard ore 68I-I or BCR No.…”