A dip-and-read test strip for the determination of mercury(II) ion in aqueous samples based on urease activity inhibition.
A sensitive dip-and-read test strip for the determination of mercury in aqueous samples based on the inhibition of urease reaction by the ion has been developed. The strip has a circular sensing zone that containing two layers: the top layer is a cellulose acetate membrane where urease is immobilized on it; the bottom layer is a pH indicator wafer that is impregnated with urea. The principle of the measurement is based on the disappearance of a yellow spot on the pH indicator wafer. The elapsing time until the disappearance of the spot which depends on the concentration of mercury(II) ion is measured with a stopwatch. Under the experimental conditions, as low as 0.2 ng/ml mercury can be observed with the detection range from 0.2 to 200 ng/ml in water. Organomercury compounds give essentially the same response as inorganic mercury. Heavy-metal ions such as Ag(I), Cu(II), Cd(II), Ni(II), Zn(II), and Pb(II) as well as other sample matrixes basically do not interfere with the mercury measurement.
Shi
Guo-Qing
GQ
Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P 0. Box 2871, Beijing 100085, China.
Jiang
Guibin
G
D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods; D002138:Calibration; D004800:Enzymes, Immobilized / Q000037:antagonists & inhibitors / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007477:Ions / Q000032:analysis; D008628:Mercury / Q000032:analysis*; D019216:Metals, Heavy / Q000032:analysis; D011934:Reagent Strips; D012015:Reference Standards; D012680:Sensitivity and Specificity; D013997:Time Factors; D014508:Urea / Q000378:metabolism; D014510:Urease / Q000037:antagonists & inhibitors* / Q000378:metabolism; D014867:Water / Q000737:chemistry*; D014873:Water Pollutants / Q000032:analysis*
D004800:Enzymes, Immobilized; D007477:Ions; D019216:Metals, Heavy; D011934:Reagent Strips; D014873:Water Pollutants; D014867:Water; D014508:Urea; D014510:Urease; D008628:Mercury