Standard curve malachite green

Standard curve of inorganic phosphate (Pi) in malachite green assay was generated with a 0.02 mM KH2PO4 solution. A serial of standard solution containing different pmol of Pi were added to 950 µl of malachite green solution. Reactions were incubated for 20 min at room temperature. Absorbance at 620 nm was measured in a cuvette with the malachite green solution as a blank. Duplicates were set up for each standard concentration and the average value of the duplicates was used for plotting the standard curve.