Determination of furosine in food products by capillary zone electrophoresis-tandem mass spectrometry

A new method for qualitative and quantitative analysis of furosine in food products by capillary electrophoresis coupled to tandem mass spectrometry (CE-MS2) has been optimized and validated. In analytical conditions, the pH value of the run buffer was similar to that of the hydrolyzed samples, which helps in avoiding interactions of the analyte with silanol groups of the inner wall of the fused silica capillary. In all previous CE methods proposed in literature, no SPE treatment has been used. The method has been applied to the analysis of food products, such as flour, having low amounts of furosine. Flour samples of different origin (wheat, chestnut, lupin, einkorn, chickpeas) have been investigated. Different food products such as pasta, milk, and tigelle bread (a typical Italian unleavened bread) were also analyzed. Some of the samples have also been analyzed by reversed-phase HPLC, and when compared to CE-MS, data obtained showed good agreement. CE-MS, in comparison to HPLC, showed advantages in terms of time of analysis and cost. The validation procedure provided good values for LOD and LOQ (respectively 0.07 and 0.25 mg L-1), recovery (77 and 97%), and precision investigated in terms of intraday repeatability (RSD%: 46% for peak areas; 12% for migration times) and intermediate precision (below 16% for peak areas, and below 7% for migration times). Therefore, the technique reported can be proposed as a powerful analytical method and a valid alternative to common traditional analytical techniques.