Colorimetric Assay for Quantification of Lactate in Test Samples

To measure the concentration of lactate, use a colorimetric assay kit to carry out duplicate analysis for the test samples. Add 10 microliters of the test samples to each well of a 96-well plate, and then add lactate assay buffer to each sample to adjust the volume to 50 microliters.

Dilute 100 millimolar L(+)-Lactate standard with lactate assay buffer to 1 millimolar. Then, into a series of wells, add 0, 2, 4, 6, 8, and 10 microliters of diluted L(+)-Lactate standard. Add 50 microliters of reaction mix into each well, and incubate at room temperature protected from light for at least 30 minutes for the color to develop.

Finally, use a microplate reader to measure the absorbance of each well at 570 nanometers. Subtract the absorbance of the background control mix from the absorbance of the reaction mix. Then, plot the lactate standard curve, and calculate the lactate concentrations from the curve by multiplying each concentration by 2.25.