Application of headspace solid phase microextraction for study of noncovalent interaction of borneol with human serum albumin

Aim:

To investigate noncovalent interactions between borneol and human serum albumin (HSA) under near-physiological conditions.

Methods:

A 65-μm polydimethylsiloxane (PDMS) fiber was selected for sampling. The extraction temperature was kept at 37 °C, and the extraction time was optimized at 10 min. Borneol solutions of different concentrations were equilibrated in 600 μmol/L HSA and 67 mmol/L phosphate buffer solution (pH 7.4, 37 °C) for 24 h prior to solid phase microextraction (SPME) using headspace mode. The binding properties were obtained based on the calculation of extracted borneol amount using gas chromatography (GC) determination.

Results:

The headspace SPME extraction method avoided disturbance from the HSA binding matrix. The recovery showed good linearity for the borneol concentrations over the range of 0.4–16.3 μmol/L with a regression coefficient (R²) of 0.9998. The limit of detection and lower limit of quantitation were determined to be 0.01 μmol/L and 0.4 μmol/L, respectively. The binding constant and the percentage binding rate were estimated to be 2.4×10³(mol/L)^-1 and 59.5%, respectively.

Conclusion:

Headspace SPME coupled to GC is a simple, sensitive and rapid method for the study of borneol binding to HSA. The method may be applied in the determination of other protein binding properties in human plasma.