Method for cleaning and/or regenerating a glass microfluidic sensor for the analysis of metals

A microfluidic method for cleaning and/or regenerating at least one microfluidic sensor comprising at least one microfluidic sensor, at least one glass microchannel forming a microfluidic circuit and at least two electrodes, wherein one of the at least two electrodes is at least a gold working electrode comprising at least the following steps:

• a step N) to clean the microfluidic circuit, comprising the four following sub-steps:
• N1:
• a sub-step to clean the microfluidic circuit, comprising an injection and circulation of a fluid sample in the at least one microchannel;
• N2:
• a sub-step to clean the at least the gold working electrode of the at least two electrodes, sub-step N2 comprising a use of sulfuric acid in the at least one microchannel to clean the at least the gold working electrode of the at least two electrodes by cyclic voltammetry, and comprising measurement of an active surface of the at least the gold working electrode of the at least two electrodes to verify that said active surface still remains equal to a target value of +/−10%;
• N3:
• a gold deposition sub-step on the at least the gold working electrode via electrochemical route using as reagents a mixture of tetrachloroauric acid and sulfuric acid;
• and
• N4:
• a control sub-step, by measuring a control solution;
• and
• a second step to clean the microfluidic circuit, comprising at least a circulation of a nitric acid solution in the at least one microchannel.