510 Bulletin USAMV-CN, 63/2007 DEVELOPMENT AND EVALUATION OF AN HPLC-DAD METHOD FOR DETERMINATION OF BENZOIC ACID IN TOMATO SAUCE AND KETCHUP Nour Violeta, I. Trandafir, Mira Elena Ionică University of Craiova, Faculty of Horticulture, Str. A.I. Cuza nr. 13, vionour@central.ucv.ro Key words: liquid chromatography, diode array detection, benzoic acid, tomato sauce and ketchup Abstract According to Directive 95/2/EC dated on 20.02.1995 of the European Union (EU), the benzoic acid belongs to the preservatives allowed conditionally, and the quantity of benzoic acid added to foods is restricted by upper limits. There are many methods available for the analysis of benzoic acid in foods and the decision as to what method should be used depends on the matrix to be analyzed. Most of the methods are for liquids and further method development may be required to adapt these methods to be applicable for all matrices. As all tomato sauce and ketchup available on our market are made with benzoic acid addition and their consumption is high, the operational parameters leading to the development of a method for the analysis of benzoic acid within tomato sauce and ketchup have been studied, the technique used is the high performance liquid chromatography together with diode array detection (DAD). It has been tried to validate the analysis method settled, in terms of sensitivity, linearity range, reproducibility, repeatability and recovery. The method provides a stable retention time and a limit of detection of 0.8 mg/kg in the sample at a signal to noise ratio of 3. For analysis, the sample is extracted or diluted with water, and the solution of the sample with the benzoic acid is purified by an extraction with Carrez reagents. The benzoic acid in the sample test solution is separated on a C18 chromatography column in a reversed phase, detected by absorbance at the wavelength of 217 nm and quantified with a calibration graph. INTRODUCTION One of the most common food, typical for the Mediteranean diet is tomatoes, tomato sauce respectively, which provides, besides β-carotene, the red carotenoidic pigment – lycopene - as a single source for this latter one. Different from the other fruit and vegetables, where the nutritious content decreases when cooking them (thermal treatment), the tomato processing determines the increase of bio-available lycopene concentration. Thus the products made of processed tomatoes such as tomato juice, tomato pasta, tomato sauce and ketchup contain the highest lycopene concentration. There are proofs that a frequent consumption of such products decreases the risk of heart attacks, cancer (especially prostate cancer), diabetes, osteoporosis and even infertility. In order to increase the life time of tomato sauce and ketchup, benzoic acid is added as a preservation agent. The benzoic acid, the sodium salt and its derivates are used for fruit, vegetable, meat, eggs, fish and margarine preservation. It has a more powerful bacterial action than the antifungal one, that increases with the pH decrease and in the presence of NaCl (it works through the undislocated molecules) [4]. The toxicity of benzoic acid as well as of the derivates is reduced. In high recurrent doses, it produces irritations of the digestive mucous membrane and decreases the digestive usage coefficient by depressing some enzymes (pepsin, trypsin, polypeptidases, D-amino acid oxidase) [12]. People worried as benzoic acid and its