By taking l-ascorbic acid and ascorbate oxidase as models, a
serpentine microfluidic channel coupled with UV/vis spectroscopy
was developed as a biosensor and applied to study the content ofAA
in dietary supplement products. The results show that physisorptively
immobilized enzymes on the PDMS surface are effective
for catalysis, and relatively stable under continuous and intense
flushing or storage at 4 ◦C. Considering that each measurement
takes only minutes, it’s applicable to use the microfluidic sensor
for drug/food/beverage analysis. We also found that the microfluidic
chip itself doesn’t have to be disposable, and enzyme can be
reloaded to reactivate the sensor for the purpose of economy. The
utilization of the enzyme-loaded microfluidic sensor is facile, and
relies on low investment in fabrication and simple detection procedure.
Furthermore, the method exhibits good anti-interference
property, reproducibility, and stability. In combination with a
miniaturized UV/vis spectrophotometer, the whole detection system
can be portable and used for on-site analysis. The principle can
be duplicated for the detection of many other food ingredients, as
long as the target substrate has a characteristic UV/vis absorbance
and can be consumed under the catalysis of a specific enzyme.
Therefore, we would expect a wide spread of the technique in food
industry and quality control department.