A novel indirect inhibitive immunoassay for determination of nicotine in human fluids
A number of methods utilizing HPLC with UV, electrochemical and fluorescence detectors, gas chromatography-mass spectrometry (GC-MS) and capillary electrophoresis have been used for the determination of nicotine (NIC) in environmental waters and biological fluids. With the development of biosensors, it may be an attractive alternative to existing analytical techniques for the detection of low concentrations of nicotine. The Biacore biosensor, based on the principle of surface plasmon resonance (SPR), is an optical device that detects changes in mass concentration at the sensor chip surface in real time. A new indirect inhibitive immunoassay using surface plasmon resonance (SPR) coupled with molecularly imprinted polymer (MIP) was developed and applied to analysis of NIC. A NIC-MIP coating capillary was produced by in situ polymerization technique and used as on-line solid phase extraction (SPE) tube before SPR detection. The anti-NIC mono-antibody was inhibited by NIC that was extracted by the MIP coating in a dose-dependent manner. The calibration curve was generated by linear fit over the range of 0.04-10.00 ng/mL. The detection limit was 0.01 ng/mL, which is lower than traditional immunoassay methods. This method has high sensitivity and can be performed automatically.