A simple and fast approach for the determination of inorganic and total mercury in aqueous slurries of biological samples using cold vapor atomic absorption spectrometry and in situ oxidation

Abstract

A simple, fast and reliable method for the determination of inorganic and total mercury in biological samples directly from slurries prepared in water has been developed using cold vapor atomic absorption spectrometry. The method does not require any standing time or heating of the slurries. Samples are simply mixed with water and measurement can be carried out immediately. For inorganic mercury determination, no additional preparation is required. For total mercury determination the samples have to be oxidized previously with a 2% m/v KMnO 4 solution for 2 minutes. After that, the measurement can be carried out similarly to that for inorganic mercury determination. The methylmercury concentration can be calculated as the difference between total and inorganic mercury. The greatest advantage of this method is that only a minimum of reagents and sample handling steps are required, which stands as a prerequisite for accurate results in routine analysis, particularly for the determination of mercury. The results were in good agreement with the 95% confidence level of the certified or close to the informed value for the reference materials investigated. The relative standard deviation was better than 7% for most of the samples. The limits of detection in the sample were determined as 0.020 and 0.016 mg g À1 for inorganic and total mercury, respectively.

On the use of certified reference materials for assuring the quality of results for the determination of mercury in environmental samples

“…These features are crucial, when the concentration of mercury in the sample is low and the matrix is complex. Advantages of CV AAS resulted in its frequent use for the determination of mercury in biological samples (Shah et al 2010; Torres et al 2009), hair (Bruhn et al 1994), slurries (Torres et al 2009), water (Krata et al 2002), and food packaging (Perring et al 2001). Cold vapor generation was also combined with atomic fluorescence spectrometry (CV AFS) (da Silva et al 2010; Li and Wang 2007) or inductively coupled plasma mass spectrometry (ICP MS) (Kenduzler et al 2012; Knight et al 1999).…”

Methylmercury determination in sub-ppb level by cold vapor analysis: facts, mechanisms and optimization

“…before the addition of NaBH4 in the sample. For this purpose the reagent KMnO4 (0.0005% w/v) was selected, due to its high oxidizing ability, which favors the conversion of MeHg to Hg 2+ and hence, the metal's atomization rate is expected to be increased [9]. According to the respective results, the combination of NaBH4 with the pre-treatment step can minimize the value of transmittance for the highest examined MeHg concentration (10 μg/L) and yields a reliable calibration curve (R 2 = 0.998).…”

“…The next step, regarding the optimization of applied method, was to investigate the effect of KMnO4 and NaBH4 concentrations, i.e. the two reagents used in the proposed MeHg determination by the cold vapor analysis, especially after proving that they can react with each other [9]. The initial MeHg concentration in each sample was 10 μg OHg/L, as the highest concentration of investigated range, while the matrix was the NSF water, as before.…”

Applicability of a magnetic bucky gel for microextraction of mercury from complicated matrices followed by cold vapor atomic absorption spectroscopy

“…The mercury determination step is relatively simple, and it has been performed by different methods including inductively coupled plasma mass spectroscopy (ICP-MS), [6] cold vapor atomic fluorescence spectroscopy (CVAFS), [7] cold vapor atomic absorption spectroscopy (CV-AAS), [8][9][10][11][12][13][14] ICP-MS, [15] and cold vapor/hydride generation atomic absorption spectroscopy (CV/HG-AAS). [16][17][18][19] Even with the high selectivity and sensitivity of above-mentioned analytical techniques, preconcentration of hazardous trace elements before their analysis is crucial due to the often very low concentrations in numerous samples (especially water samples). However, most of the sample preparation methods applied to extract the trace amounts of mercury from various samples are costly and time-consuming.…”