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Title: Determination of Benzoic Acid and Benzene in Soft Drinks, Fruit Juices and Herbal Products Using High Performance Liquid Chromatography
Authors: Kusi, James Kwame
Issue Date: 2-Dec-2013
Abstract: Benzoic acid is one of the most commonly used food preservatives. Benzoic acid and its salts are permitted food additives by international laws in processing in restrictive amounts, but their content must be declared and must not exceed the established limits by legislation. The level of benzoic acid in different brands of soft drinks, fruit juices herbal products available on the markets, stores and pharmaceutical shops in Kumasi, Ghana were determined by high performance liquid chromatography with a UV detector. Chromatographic separation was achieved with Phenomenex synergi 4µ polar – RP 80A 15 × 2 mm 4 micron column with ammonium acetate buffer (pH = 4.4) and acetonitrile (90:10) as the mobile phase and 0.4 mL/min as the flow rate for the benzoic acid determination. A mixture of methanol and water (70:30) was used as the mobile phase for the benzene analysis with a flow rate of 0.8 mL/min. The concentrations of benzoic acid and benzene in all the samples (soft and fruit drinks) were calculated by external standard method with a calibration of correlation coefficient of 0.9980 and 0.9933 respectively from the standards calibration curves. The range of concentrations were from below detection limit to 2004 mg/L. Thirty four (34) different brands of soft drinks, 16 different brands of fruit juices and 25 different kinds of herbal products were analysed. The herbal products had high concentrations of benzoic acid than the soft drinks and fruit juices. The ranges of concentration of benzoic acid were from below detection to 548.00 mg/L for soft drinks; below detection limit to 140.07 mg/L for fruit juices; and 0.10 to 2004 mg/L for herbal products. The estimated daily intake of benzoic acid for soft drinks and fruit juices for adults was 0.13 mg/L and 0.00072 mg/L respectively which were within the range of the acceptable daily intake (ADI) of benzoic acid (0-5 mg/L of body weight). Five of the soft drink samples contained levels of benzoic acid above the 150 mg/L which is the limit set by World Health Organization (WHO), while all the fruit juices were within the range. Benzene was not detected in any of the soft drinks and fruit juices. The reproducibility of the method was good with a coefficient variation of 3.11%. The mean recoveries for the samples ranged from 107 to 110%. The limit of detection and quantification for benzoic acid analysis was 0.03 mg/L and 0.10 mg/L respectively and that for benzene analysis was 0.06 mg/L and 0.20 mg/L respectively.
Description: A thesis submitted to the School of Graduate Studies, Kwame Nkrumah University of Science and Technology in partial fulfilment of the requirement for the award of Master of Philosophy in Analytical Chemistry, March-2013
URI: http://hdl.handle.net/123456789/5307
Appears in Collections:College of Science

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