Adaptation of glass columns for clean-up RP-HPLC determination of aflatoxins with post-column derivatisation with bromine and fluorescence detection.

Abstract

Consumption of aflatoxin-contaminated foods in developing countries may not only cause cancer in the general population, but is also associated with stunting and immune suppression in children. Accurate determination of aflatoxins in foods is important for the prevention of the above health risks. This study aimed to evaluate the possibility of using cheap florisil-packed glass columns instead of relatively complex and expensive pre-packed cartridges for afltoxin clean-up prior to HPLC analysis. Additionally, effects of aflatoxin extract storage temperature, and themoisture content of florisil on aflatoxin recovery were assessed. Results showed that the standard curve was highly linear as depicted by the high correlation coefficient for all four aflatoxins [0.99, 0.99, 0.97 and 0.98, respectively for AFG1, AFB2 and AFB1 and AFG2. The retention times over a total run time of 20 minutes were 14.8 (SD 0.4), 12.4 (SD 0.1), 10.7 (SD 0.3) and 9.1 (SD 0.3) minutes, respectively for AFB1, AFB2, AFG1 and AFG2. Florisil powder that had been dried for 12 hours at 100 oC, then hydrated with water at 5% (w/v) before packing on glass columns gave slightly higher recovery for all aflatoxins (100.3% AFB1, 93.1% AFB2, 83.8% AFG1 and 71.1% AFG2) compared to the pre-packed cartridges (96.4% AFB1, 91.5% AFB2, 80.6% AFG1 and 66.9% AFG2). There was 10% and 20% aflatoxin loss at 4 oC and 22 oC, respectively. After 6 hours of storage, no aflatoxin degradation was observed at – 18 oC. There was 0-5% aflatoxin loss at –18 oC after 12 hours, while at 4 oC and 22oC, the loss range was 20-50% and 30-55%, respectively. Aflatoxin recoveries ranged from 120-160%, 90-110%, 80-98%, and 55-74% for florisil which had been hydrated with water at 2.5%, 5% and 10%, respectively. Glass columns are cheap and can be used many times and are a feasible and sustainable alternative to pre-packed florisilcartridges for aflatoxin clean up to ensure food safety, especially in resource poor settings.