A label free electrochemical immunosensor for sensitive detection of porcine serum albumin as a marker for pork adulteration in raw meat

• A first electrochemical immunosensor report on sensitive detection of porcine serum albumin.
• The reported sensor exhibited excellent specificity against albumins from other species.
• Successfully applied to real samples with satisfactory recovery of analytes.
• Sensitive, and suitable for on-site pork adulteration detection in raw meat.

A label free electrochemical immunosensor for sensitive detection of porcine serum albumin (PSA) is reported in this work. The immunosensor was constructed by first electrochemically reducing 4-carboxyphenyl diazonium salt, which had been electrochemically generated in situ, to a stable 4-carboxyphenyl layer on carbon nanofiber-modified screen printed electrode. Antibodies were covalently attached onto the electrode using carbodiimide chemistry between the carboxylic groups of the 4-carboxyphenyl layer and amine groups of the antibody. Using the strong affinities of serum albumins towards anions, the increase in cathodic peak current in anionic redox probe after immunocomplex formation with antibodies was used for PSA detection. The reported immunosensor demonstrated a linear range from 0.5 to 500 pg/mL for the measurement of PSA with detection limit of 0.5 pg/mL in buffer solution. Cross-reactivity studies have shown excellent specificity with satisfactory recovery of PSA in fresh meat samples without the need of sample dilution.