Quality control of fish sauce by simultaneous determination of histamine and tyramine with capillary electrophoresis and contactless conductivity detection

Abstract

In this study, we report the development of a simple and cost-effective approach for fish sauce quality control. This is based on simultaneous determination of histamine and tyrosine in fish sauce using capillary electrophoresis (CE) coupled with contactless conductivity detection (C⁴D). Considerations for the use of purpose-made CE-C⁴D for food quality control in Vietnam are provided. The best detection limit (LOD) achieved was 5 mg/kg for histamine and 6 mg/kg for tyramine using the optimized background electrolyte (BGE) composed of 20 mM (N-(2-Hydroxyethyl)piperazine-N’-(2-ethane-sulfonic acid]) (HEPES) / 10 mM L-Histidine (His), 5 % methanol (MeOH) at pH 6.6. Excellent agreement between the results from CE-C⁴D and those from the confirmation method (HPLC-PDA for histamine and HPLC-FLD for tyramine) was achieved for different fish sauce samples, with their result deviations less than 10 % for all tested compounds.