Slurry sampling for Hg determination in sediments, sewage sludge and coal samples by cold vapor atomic absorption spectrometry

Abstract

Um método simples e robusto para a determinação de Hg em amostras ambientais por espectrometria de absorção atômica com geração de vapor frio diretamente de suspensões ácidas é proposto. Após redução do tamanho das partículas da amostra para ≤ 50 µm em gral de ágata, dois procedimentos foram utilizados para a preparação das suspensões: com 6,7% v/v de ácido nítrico ou 10% v/v de água-régia mais 2% v/v de ácido fluorídrico. Dependendo da amostra, a concentração da amostra na suspensão variou de 3,3 a 23 mg mL -1 . O vapor frio de Hg gerado diretamente das suspensões ácidas das amostras foi conduzido para o tubo T de quartzo, posicionado no lugar do atomizador do espectrômetro. Oito amostras ambientais de referência certificadas foram analisadas. Pelo uso da calibração convencional com padrões aquosos, excelentes resultados foram obtidos quando a água-régia mais o ácido fluorídrico foram utilizados nas suspensões. Amostras de sedimento e carvão de Santa Catarina, Brasil, também foram analisadas. O limite de detecção foi de 30 ng g -1 .Simplicidade, baixo custo e alta eficiência são algumas qualidades do método proposto, mostrandose adequado para análises de rotina.A simple and robust method for the determination of Hg in environmental samples by slurry sampling cold vapor generation atomic absorption spectrometry is proposed. After reducing the sample particles size to ≤ 50 µm in an agate mortar, two procedures were used in the slurry preparation: either using 6.7% v/v nitric acid only or 10% v/v aqua regia plus 2% v/v hydrofluoric acid medium. Depending on the sample, the slurry concentrations varied from 3.3 to 23 mg mL -1 . The mercury cold vapor generated directly from the acidified sample slurry was conducted to quartz T tube, placed in the atomizer of the spectrometer. Eight certified environmental materials were analyzed. By using the conventional calibration against aqueous standard solutions, excellent results were obtained when aqua regia plus hydrofluoric acid was used as the slurry medium. Sediment and coal samples from Santa Catarina, Brazil were also analyzed. The obtained limit of detection was 30 ng g -1 . Simplicity, low cost and high efficiency are some of the qualities of the proposed method, making it adequate for routine analysis.

The Effect of Atmosphere on Elemental Mercury Release During Thermal Treatment of Two Bituminous Coals

“…2 Hg has the persistence and bioaccumulation character, which can strongly affect the environment as well as the human health. 3,4 Therefore, more and more attention has been paid to the Hg emission control from coal-fired power plants. [5][6][7][8][9] Also, a series of strict policies for controlling Hg emissions have been established, including the emission standard of air pollutants for coal-fired power plant in China.…”

Evaluation of slurry preparation procedures for the determination of mercury by axial view inductively coupled plasma optical emission spectrometry using on-line cold vapor generation

“…In this way, the aqua regia concentration was 10% v/v and the HF concentration was 2% v/v in the final slurry. Before being measured, two drops of antifoaming agent were added to the slurry and it was vigorously stirred manually for 30 s. This slurry preparation procedure was previously used for environmental samples, including coal samples [18,20]. Procedure 2: same as Procedure 1, except that the volume was made up with water after the first 30 min in the ultrasonic bath, and the slurry was immediately measured after adding two drops of the antifoaming agent and vigorous stirring.…”

“…Segade and Tyson [16] evaluated two flow injection systems for Hg speciation analysis in fish tissue samples by slurry sampling CV AAS. Ribeiro et al proposed a method for the determination of Hg, in certified environmental samples by on-line cold vapor generation ICP mass spectrometry [17] and on-line CV AAS [18], using slurry sampling in both procedures.…”

Determination of Hg in Biological Samples and Ethanol Fuel by Photochemical Vapor Generation after Pre-Concentration in a Gold Trap

“…In this way, a sensitive analytical technique is required and the cold vapor atomic absorption spectrometry (CV AAS) using a chemical reduction is the most consolidated for the determination of this element. [9][10][11][12] Determination of Hg in Biological Samples and Ethanol Fuel by Photochemical Vapor Generation J. Braz. Chem.…”