IJSRP, Volume 5, Issue 4, April 2015 Edition [ISSN 2250-3153]
Yemane Tadesse, Rishi Pal, Abraha Tadese, Amaha Woldu, Ram C Saini
Caffeine, available in plant’s kingdom worldwide, has remarkable insecticidal, weedicide, beverage and medicinal values, along with a few fatal actions to humanity if uptake is beyond limit. For healthy cause, it’s reckoning at trace level in local drinks and pharmaceutical of routine use has become vital. An environment friendly chemically modified carbon paste sensor has been fabricated. Square wave voltammetry technique has been deployed to carry the present investigations in procured real samples of routine use medicines and local drinks in Mekelle city. Experimental conditions and square wave parameters have been optimized with prepared sensor for anodic oxidation of caffeine in buffer. The peak signal observed two-fold upswing in presence of this sensor as compared to unmodified sensor. Adequate catalytic activity of anthraquinone and irreversible nature of oxidation process at the interface has been observed. The perceived effect of analyte concentration on both signals i.e. peak current and peak potential exposed mainly the diffusion controlled mechanism at interface, besides some interfering surface processes at high caffeine concentrations. The peak current and caffeine concentration observed linear dependence in low range 0.00 – 100 μM with correlation coefficient ‘R’ = 0.9999 (n = 10) and standard deviation ‘σ’ = 0.0596. The observed regression equation is “Ip(μA) = 34.465 + 1.282C(μM)” with the detection limit of 0.1395 μM. Caffeine quantification conducted in local available drinks and medications by using standard addition/spiked method have yielded very good recovery. An electro-oxidation process of caffeine at the interface received resilient catalytic action of modifier. Excellent recovery of caffeine’s spiked samples of drugs and local drinks represent an inordinate potential of sensor for its prompt quantification in real samples.