Catalytic determination of ultra trace amounts of tellurium by 2.5-order differential oscillopolarography.
A highly sensitive and selective catalytic method with 2.5-order differential oscillopolarographic detection is described for the determination of tellurium, based on its activation effect on the slow Pd(II)-catalyzed reaction of sodium hypophosphite and methyl red in hydrochloric acid medium at 100 degrees C. Methyl red exhibited a sensitive 2.5-order differential polarographic wave at -0.35 V (vs. SCE) in the supporting electrolyte of pH 5.0 acetate buffer solution and was chosen as the indicating component for the indirect determination of tellurium. A calibration curve of tellurium in the range of 0.02-2.0 ng mL(-1) was obtained by the fixed-time procedure. The detection limit was 0.007 ng mL(-1). Possible interferences by co-existing substances were examined. The new method has been used to analyze trace tellurium in organs of white mice with satisfactory results. RSD was 0.54% to 2.10%, recovery 98.4% to 95.7%. The mechanism is also discussed.
Department of Chemistry, East China Normal University, Shanghai.
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Fang
D001391:Azo Compounds; D002384:Catalysis; D007202:Indicators and Reagents; D009991:Oscillometry; D011048:Polarography / Q000379:methods; D012680:Sensitivity and Specificity; D013691:Tellurium / Q000032:analysis*
D001391:Azo Compounds; D007202:Indicators and Reagents; C008492:methyl red; D013691:Tellurium