Biotin content of paediatric formulae, early lactation milk and seasonal bovine milk powders by biosensor immunoassay

An optical biosensor assay utilising a monoclonal antibody was developed for the quantitation of the biotin content of milk and paediatric formulae. The method provides a reliable estimate of total biotin accomplished by simple aqueous extraction, combined with heat treatment, prior to automated biosensor analysis. The binding assay was configured under inhibition conditions utilising a sensor surface functionalised with biotin and was subjected to single-laboratory validation. Critical assay factors, including calibration parameters, cross-reactivity, non-specific binding and matrix interferences were evaluated systematically. Assay performance parameters including range, detection limits, precision, recovery and bias were estimated. The method was applied to the routine compliance testing of paediatric formulae and the temporal change in the biotin content of early lactation milk and seasonal milk powder. The assay is an expedient alternative to current HPLC, microbiological and proprietary kit-based immunoassay methods for the determination of the biotin content of milk-based foods.