Method validation for the detection of formaldehyde in fish using ultra performance liquid chromatography

Abstract

Formaldehyde, the simplest aldehyde, tops the list of illegal and harmful food contaminants. Recently, formaldehyde has been used indiscriminately to preserve the freshness and quality of fish. Numerous incidents of formalin (a solution of formaldehyde) misuse during the storage and transportation of fish have been reported in several parts of India. In this context, it is pertinent to study formalin contamination in fish and shellfish. Protocol for detection of free and bound formaldehyde by ultra-performance liquid chromatography (UPLC) was attempted in the present study. Formaldehyde peak was observed in the expected retention time and standardisation of the protocol for formaldehyde determination was then carried out. UPLC method was developed and validated for specificity, repeatability, accuracy, and linearity. The average correlation coefficient (R2) was 0.99. The recovery rates of free and bound formaldehyde were 90.83 to 116.43% and 88.76 to 132.98%, respectively. The limit of detection (LOD) was found to be 0.5 ppm. The study investigated free and bound formaldehyde levels in commonly traded fish species across five major fish markets in Tamil Nadu, India. Sphyraena barracuda had the highest recorded concentrations of free and bound formaldehyde at 9.8 and 6.45 mg kg-1, respectively, while Lethrinus lentjan exhibited the lowest concentrations at 0.8 mg kg-1 for free formaldehyde and 0.5 mg kg-1 for bound formaldehyde.