LC-MS/MS method for determination of very low levels of benzoate/benzoic acid

Benzoic acid is widely present in nature in the form of free acid, ester or its derivatives. It is mainly used for the preparation of sodium benzoate preservative, and for the synthesis of medicines and dyes, and also for the preparation of plasticizers, mordants, fungicides and perfumes. Although these preservatives are legally used, they can be harmful if the uptake by a body is higher than the permitted limits, which cause allergic effects, such as urticaria, non-immunological contact urticaria and asthma, renal failure, etc. As a result, analysis of benzoic acid is an important issue for the food industry, regulatory authorities, and pharmaceutics. LC-MS/MS methods are more sensitive in determination of benzoic acid than HPLC and GC-MS methods. However, a use of acidified mobile phases to get chromatographic retention on reversed-phase columns causes signal suppression in mass spectrometry. In order to determine very low levels of benzoic acid with LC–MS/MS method, we removed this contradiction applying chromatography on HILIC column, increasing the sensitivity six-fold.