Manganese atomic absorbance in sodium chloride matrix and a complex serum sample was individually studied on a tungsten filament atomizer by electrothermal atomic absorption. The low cost, compact filament atomizer used a purge gas of 90% Ar and 10% H2 to improve the sensitivity of Mn analyte and prevent the filament oxidation. A low-voltage power supply heats the filament in five steps of sample analysis with required time. The pyrolysis and atomization temperature for Mn aqueous samples were 1500K and 2250K, respectively, and shifted to 1000K and 2200K for chloride salt and serum-containing samples with ascorbic acid as a matrix modifier. While the charring temperature for chloride matrix containing ammonium nitrate modifier recorded to be 1300K. Presence of sodium chloride salt showed that high concentration of NaCl interference caused depressive effects on atomic Mn absorbance below 1000K charring degree, even though above 1000K Mn lost as MnCl. The addition of ascorbic acid and ammonium nitrate as chemical modifiers to chloride and serum samples were promoted the atomic signal and the pyrolysis temperature of Mn analyte respectively. From results, sodium chloride interference is dependent on temperatures and presence of modifiers. In contrast horse serum is independent from chemical modifiers and temperatures. Under optimal conditions, Mn-spiked serum samples can be determined using aqueous calibration standards. Limits of detection for aqueous samples and serum samples were 4.1 and 5.8 ng/mL, respectively. Elimination of the influence of the serum matrix required careful selection of the pyrolysis temperature and time-gated integration of the absorbance results.
|Commitee:||De Meo, Cristina, Lu, Yun|
|School:||Southern Illinois University at Edwardsville|
|School Location:||United States -- Illinois|
|Source:||MAI 55/06M(E), Masters Abstracts International|
|Keywords:||Electrothermal atomic absorption, Mathematical integration, Tungsten atomizers|
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