Spectrophotometric determination of acetone in acetic acid

A sensitive and selective spectrophotometric method for the determination of acetone in acetic acid has been worked out. It is based on the reaction of acetone with diazotized p-aminobenzoic acid in a strongly alkaline medium to form a purple color with maximum absorption at 540 nm. Beer's law holds up in the range 20–140 μg of acetone in a final volume of 20 ml, with a molar absorptivity of 8.1 × 10³ liters mol^?1 cm^?1, sensitivity index of 0.0072 μg cm^?2, relative error of ?1.9 to +0.6%, and relative standard deviation of 0.7–3.5, depending on the concentration level. Furthermore, the color reaction is fast, and the procedure is simple, and avoids the use of an extraction.