Mercury determinations in biohazard samples by GFAAS using Noviplex card sampling.

• DOI: https://doi.org/10.22533/at.ed.1652412074

• Palavras-chave: Noviplex cards, mercury in biological samples, electrothermal atomization, chemical modifier.

• Keywords: Noviplex cards, mercury in biological samples, electrothermal atomization, chemical modifier.

• Abstract: This paper presents a new method for sampling biohazard samples (mercury-contaminated human and fish blood/plasma and muscle and liver tissue homogenates) using percolation on Noviplex cards for total mercury determination by graphite furnace atomic absorption spectrometry (GFAAS). For the sampling process, 50 µL of the biological samples was percolated onto the sampling disk of the Noviplex card. Three minutes after percolation of the sample aliquot, the sample adsorbed on the card-sampling disk was already dry and showed stability at room temperature for six months. After the sampling process, the card sampling discs with the percolated samples were mineralized in an acidic medium containing 18 mol L-1 H2SO4 and 0.02 mol L-1 KMnO4 in a 1.0:0.50 (v/v) ratio. Mercury determinations of the acid extracts were performed via GFAAS by injecting 15 µL of sample + 5 µL of zirconium nitrate (chemical modifier) into the graphite tube of the spectrometer, in which the inner wall was coated with tungsten carbide (permanent chemical modifier). The reaction conditions provided thermal stabilization of mercury at atomization temperatures up to 1700 °C. The method was validated for total mercury determinations with extracts from DORM-4 and DOLT-4 reference materials. The calculated LOD and LOQ ranged from 12 to 43 µg kg-1, respectively. The sampling method proved to be quite robust for mercury determinations for biohazard samples. This paper presents a new method for sampling biohazard samples (mercury-contaminated human and fish blood/plasma and muscle and liver tissue homogenates) using percolation on Noviplex cards for total mercury determination by graphite furnace atomic absorption spectrometry (GFAAS). For the sampling process, 50 µL of the biological samples was percolated onto the sampling disk of the Noviplex card. Three minutes after percolation of the sample aliquot, the sample adsorbed on the card-sampling disk was already dry and showed stability at room temperature for six months. After the sampling process, the card sampling discs with the percolated samples were mineralized in an acidic medium containing 18 mol L-1 H2SO4 and 0.02 mol L-1 KMnO4 in a 1.0:0.50 (v/v) ratio. Mercury determinations of the acid extracts were performed via GFAAS by injecting 15 µL of sample + 5 µL of zirconium nitrate (chemical modifier) into the graphite tube of the spectrometer, in which the inner wall was coated with tungsten carbide (permanent chemical modifier). The reaction conditions provided thermal stabilization of mercury at atomization temperatures up to 1700 °C. The method was validated for total mercury determinations with extracts from DORM-4 and DOLT-4 reference materials. The calculated LOD and LOQ ranged from 12 to 43 µg kg-1, respectively. The sampling method proved to be quite robust for mercury determinations for biohazard samples. This paper presents a new method for sampling biohazard samples (mercury-contaminated human and fish blood/plasma and muscle and liver tissue homogenates) using percolation on Noviplex cards for total mercury determination by graphite furnace atomic absorption spectrometry (GFAAS). For the sampling process, 50 µL of the biological samples was percolated onto the sampling disk of the Noviplex card. Three minutes after percolation of the sample aliquot, the sample adsorbed on the card-sampling disk was already dry and showed stability at room temperature for six months. After the sampling process, the card sampling discs with the percolated samples were mineralized in an acidic medium containing 18 mol L-1 H2SO4 and 0.02 mol L-1 KMnO4 in a 1.0:0.50 (v/v) ratio. Mercury determinations of the acid extracts were performed via GFAAS by injecting 15 µL of sample + 5 µL of zirconium nitrate (chemical modifier) into the graphite tube of the spectrometer, in which the inner wall was coated with tungsten carbide (permanent chemical modifier). The reaction conditions provided thermal stabilization of mercury at atomization temperatures up to 1700 °C. The method was validated for total mercury determinations with extracts from DORM-4 and DOLT-4 reference materials. The calculated LOD and LOQ ranged from 12 to 43 µg kg-1, respectively. The sampling method proved to be quite robust to mercury determinations in biohazard samples.