doi:10.1038/nindia.2011.135 Published online 26 September 2011
Researchers have designed a new antimony sensor by coating a carbon paste electrode (CPE) with rice husk (RH) and hexathia 18C6 (HT18C6), an organic compound. The sensor is capable of detecting minute traces of antimony in drugs, human hair and blood samples.
Antimony, commonly used is leishmaniasis drugs, is toxic in excess amounts and can cause severe health problems. Existing techniques for detecting antimony are time-consuming and costly.
To devise a cost-effective detection method, the researchers modified a CPE with RH and HT18C6. They tested the efficacy of their HT18C6–RH–CPE electrode for detecting antimony in anti-leishmanial drugs, human hair, blood samples, urine and sea water. They compared the efficacy of HT18C6–RH–CPE with three other electrodes: plain CPE, RH–CPE and HT18C6–CPE.
In electrochemical studies, the researchers found that the peak current of HT18C6–RH–CPE was dramatically higher than that of plain CPE. Rice husk is a good adsorbent of antimony and HT18C6 can form metal complexes with antimony; these effects combine to provide HT18C6–RH–CPE with a lower charge transfer resistance and higher current than other electrodes.
HT18C6–RH–CPE was also better than the other electrodes for detecting antimony in the presence of interfering metal ions. The study indicates that HT18C6–RH–CPE is stable and could be used to perform repeated measurement over periods of around three months.
"Besides the detection of antimony, this research proves that abundantly available natural materials such as rice husk could be used for the analysis of metals and organic molecules," says lead researcher Ashwini K. Srivastava.