Chandra, Ajenesh and Maata, Matakite and Prasad, Surendra (2019) Determination of iodine content in Fijian foods using spectrophotometric kinetic method. Microchemical Journal, 148 . pp. 475-479. ISSN 0026-265X
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Abstract
The spectrophotometric kinetic method was validated for the determination of iodine in different food samples. The method is based on the iodide catalysed reduction of Ce4+ to Ce3+ by As3+. The absorbance of the kinetic indicator reaction was measured at 370 nm for exactly 1 min at 37 °C. The change in absorbance per min, as a measure of initial rate, was plotted against the different iodine concentrations to achieve a linear calibration equation with the R2 value of 0.9998 which showed excellent reproducibility. The limit of detection (LOD) was 1.54 ng/mL and the limit of quantification (LOQ) was 4.90 ng/mL. The incineration of the food organic matter was achieved by ashing the food samples at 600 °C using KOH and ZnSO4 in steps for 3 h. Trace levels of iodine (ng) were determined successfully using the validated spectrophotometric kinetic method for the 9 food samples (36 sub-samples). The Fiji seaweeds, lumiwawa (brown seaweed) showed the highest iodine content being 6373.30 ± 0.39 ng/g followed by sea grapes (green seaweed) 1162.81 ± 0.61 ng/g, lettuce 114.81 ± 0.08 ng/g, English cabbage 108.40 ± 0.06 ng/g, Chinese cabbage 104.01 ± 0.06 ng/g, pumpkin 101.24 ± 0.08 ng/g, long bean 97.61 ± 0.10 ng/g, banana 76.18 ± 0.10 ng/g and tomato 40.32 ± 0.04 ng/g. The coefficient of variation for the sample analysis was <5.31% with a mean and standard deviation of 2.55 ± 0.17% for the food samples analysed. The recovery analysis of iodine from standard samples ranged from 99.84 ± 0.91% to 100.24 ± 5.92% with an excellent average recovery of 100.06 ± 3.16%. The analytical coefficient of variation was calculated to be 0.34% for the food samples analysed. This shows exceptional system analytical stability of the method used in this study.
| Item Type: | Journal Article |
|---|---|
| Subjects: | Q Science > QD Chemistry |
| Divisions: | Faculty of Science, Technology and Environment (FSTE) > School of Biological and Chemical Sciences |
| Depositing User: | Ms Shalni Sanjana |
| Date Deposited: | 17 Feb 2020 23:42 |
| Last Modified: | 15 Mar 2021 02:32 |
| URI: | https://repository.usp.ac.fj/id/eprint/11988 |
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