To measure the amount of ascorbic acid (vitamin C) using electrochemical biosensing, you can employ a technique called amperometry. Amperometry is a common electrochemical method used for the detection and quantification of various analytes, including ascorbic acid.
Here is a general procedure for measuring ascorbic acid using amperometry in an electrochemical biosensing setup:
Preparation of Electrochemical Biosensor: Start by preparing your electrochemical biosensor specific for ascorbic acid detection. This biosensor typically consists of a working electrode, reference electrode, and counter electrode. The working electrode is often modified or functionalized with a material that facilitates the electrochemical oxidation of ascorbic acid.
Calibration: Before analyzing your samples, you need to calibrate the biosensor. Prepare a series of standard solutions with known concentrations of ascorbic acid. You can create a calibration curve by measuring the current response at different concentrations of ascorbic acid using the biosensor. This will establish a relationship between the measured current and the concentration of ascorbic acid.
Sample Analysis: Take your sample solution that contains ascorbic acid and place it onto the working electrode of the biosensor. Ensure that the sample covers the electrode area. Apply a suitable potential to the working electrode to oxidize ascorbic acid. This potential should be within the range where only ascorbic acid is oxidized, without interference from other components in the sample.
Current Measurement: Ascorbic acid is oxidized at the working electrode, resulting in a current flow. This current is proportional to the concentration of ascorbic acid in the sample. Measure the resulting current using an amperometer or potentiostat connected to the biosensor.
Quantification: Using the calibration curve generated earlier, determine the concentration of ascorbic acid in your sample based on the measured current response. The calibration curve allows you to relate the measured current to the corresponding concentration of ascorbic acid.
It's worth noting that the specific details of the electrochemical biosensing setup and measurement parameters can vary depending on the particular biosensor and instrument being used. Therefore, it's important to consult the manufacturer's instructions and relevant literature for the specific techniques and parameters appropriate for your biosensor system.