Assay of Erythromycin in Giant Freshwater Prawn (Macrobrachium Rosenbergii) by a Fast Scanning Stripping Square Wave Voltammetry at the Slowly Dropping Mercury Electrode
Erythromycin A (EA) is one of the antibiotics limited in seafood products in general and in giant freshwater prawns (Macrobrachium rosenbergii) in particular, meant for export to the US, EU, Japan and Canada. There are many methods used in assaying this antibiotic in giant freshwater prawns such as ELISA, HPLC, LC-MS/MS, GC-MS, etc. However, these methods require costly equipment, time-consuming analysis and costly reagents among others. A fast scanning, stripping square wave voltammetry at the slowly dropping mercury electrode was primarily developed and validated to quantify this antibiotic in order to achieve speed of analysis at low costs. Electrochemical signals were measured at potential wave, -1430 mV. The optimal experimental materials for the method were, supporting electrolyte, ammonium acetate 0.1 M, pH 8.0, the solvents for dissolving erythromycin standard (acetonitril, Vstart = -400 mV, Vstop = -1700 mV, Vstep = 6 mV, Vpulse = 40 mV, Tdrop = 5000 ms, Velctrolise = -1100 mV, Telectrolise = 5 s). The method showed high recovery (≥ 90.40 %), high sensitivity (lower limit of detection, LoD = 0.57 µg.kg-1) and high precision (RSD ≤ 1.58%) as well as excellent linearity (r2adjusted ≥ 0.99999). These results demonstrate that the method could be used as a simple and rapid analytical screening technique for the detection of erythromycin in giant freshwater prawn muscle.