Table 1.

Comparison between spectrophotometric and HPLC methods in terms of standard deviation, recovery%, and RSD%.

Method	Glyoxylic acid concentration in the mixture M	Determined glyoxylic acid in the mixture M∗	Standard deviation ± M	Recovery (%)	RSD (%)
Spectrophotometric	0.35	0.354	0.00132	101	0.37
	0.50	0.504	0.00110	109	0.22
HPLC	0.35	0.361	0.00466	103	1.29
	0.50	0.508	0.00457	102	0.90

^∗Samples diluted 25 times in the spectrophotometric determination only. RSD: relative standard deviation.