Square wave cathodic stripping voltammetric technique for determination of aflatoxin B1 in ground nut sample

Abstract

An electroanalytical method has been developed for the detection and determination of 2,3,6a,9a-tetrahydro-4-methoxycyclo penta[c] furo[3’,2’:4,5] furo [2,3-h][l] benzopyran-1,11-dione (aflatoxin B1, AFB1) by a square wave cathodic stripping voltammetric (SWSV) technique on a hanging mercury drop electrode (HMDE) in aqueous solution with Britton-Robinson Buffer (BRB) at pH 9.0 as the supporting electrolyte. Effect of instrumental parameters such as accumulation potential (Eacc), accumulation time (tacc), scan rate (v), square wave frequency, step potential and pulse amplitude were examined. The best condition were found to be Eacc of -0.8 V, tacc of 100 s, v of 3750 mVs-1, frequency of 125 Hz, voltage step of 30 mV and pulse amplitude of 50 mV. Calibration curve was linear in the range of 0.01 to 0.15 uM with a detection limit of 0.125 x 10-8 M. Relative standard deviation for a replicate measurement of AFB1 (n = 5) with a concentration of 0.01 ?M was 0.83% with a peak potential of -1.30 V (against Ag/AgCl). The recovery values obtained in spiked ground nut elute sample were 94.00 ± 0.67 % for 3.0 ppb, 91.22 ± 1.56 % for 9 ppb and 92.56 ± 2.00 % for 15.0 ppb of AFB1. The method was applied for the determination of the AFB1 in ground nut samples after extraction and clean-up steps. The results were compared with that obtained by high performance liquid chromatography (HPLC) technique. Abstrak Satu kaedah elektroanalisis telah dibangunkan untuk mengesan dan menentukan 2,3,6a,9a-tetrahydro-4-methoxycyclo penta[c] furo[3’,2’:4,5] furo [2,3-h][l] benzopyran-1,11-dione (aflatoxin B1, AFB1) menggunakan teknik voltammetri perlucutan katodik denyut pembeza di atas elektrod titisan raksa tergantung (HMDE) di dalam larutan akuas dengan larutan penimbal Britton-Robinson (BRB) pada pH 9.0 bertindak sebagai larutan penyokong. Kesan parameter peralatan seperti keupayaan pengumpulan (Eacc), masa pengumpulan (tacc), kadar imbasan (v), frekuensi gelombang bersegi, kenaikan keupayaan dan amplitud denyut telah dikaji. Keadaan terbaik yang diperolehi adalah Eacc; -0.8 V, tacc; 100 s, v; 3750 mV/s, frekuensi; 125 Hz, kenaikan keupayaan; 30 mV dan amplitud denyut; 50 mV. Keluk kalibrasi adalah linear pada julat diantara 0.01 ke 0.15 ?M dengan had pengesan pada 0.125 x 10-8 M. Sisihan piawai relatif untuk 5 kali pengukuran AFB1 dengan kepekatan 0.01uM ialah 0.83 %. Nilai perolehan semula di dalam larutan elusi sampel kacang yang disuntik dengan 3.0 ppb, 9 ppb dan 15.0 ppb AFB1 adalah 94.00 ± 0.67 %, 91.22 ± 1.56 % dan 92.56 ± 2.00 % masing-masingnya. Kaedah ini telah digunakan untuk menentukan kandungan AFB1 di dalam sampel kacang tanah selepas proses pengekstraksian dan pembersihan dijalankan