Determination of human serum albumin using aurothiomalate as electroactive label.
A new electroactive label has been used to monitor immunoassays in the determination of human serum albumin (HSA) using glassy-carbon electrodes as supports for the immunological reactions. The label was a gold(I) complex, sodium aurothiomalate, which was bound to rabbit IgG anti-human serum albumin (anti-HSA-Au). The HSA was adsorbed on the electrode surface and the immunological reaction with gold-labelled anti-HSA was then performed for one hour by non-competitive or competitive procedures. The gold(I) bound to the anti-HSA was electrodeposited in 0.1 mol L-1 HCl at -1.00 V for 5 min then oxidised in 0.1 mol L-1 H2SO4 solution at +1.40 V for 1 min. Silver electrodeposition at -0.14 V for 1 min followed by anodic stripping voltammetry were then performed in aqueous 1.0 mol L-1 NH(3)-2.0x10(-4) mol L-1 AgNO3. For both non-competitive and competitive formats, calibration plots in the ranges 5.0x10(-10) to 1.0x10(-8) mol L-1 and 1.0x10(-10) to 1.0x10(-9) mol L-1 HSA, respectively, with estimated detection limits of 1.5x10(-10) mol L-1 (10 ng mL-1) and 1.0x10(-10) mol L-1 (7 ng mL-1), respectively, were obtained. Levels of HSA in two healthy volunteer urine samples were also evaluated, using both immunoassay formats.
de la Escosura-Muñiz
Alfredo
A
Departamento de Química Física y Analítica, Universidad de Oviedo, 33006, Oviedo, Asturias, Spain.
González-García
María Begoña
MB
Costa-García
Agustín
A
D004563:Electrochemistry; D004566:Electrodes; D006046:Gold / Q000737:chemistry; D006052:Gold Sodium Thiomalate / Q000737:chemistry*; D006801:Humans; D007118:Immunoassay / Q000379:methods; D012680:Sensitivity and Specificity; D012709:Serum Albumin / Q000032:analysis*; D012834:Silver / Q000737:chemistry
D012709:Serum Albumin; D006052:Gold Sodium Thiomalate; D012834:Silver; D006046:Gold