Spectrophotometric method	Amount taken (μg∙ml⁻¹)	Recovery (% ± RSD)^a
Spectrophotometric method	Amount taken (μg∙ml⁻¹)	Initial rate method	Fixed time method
		Intra-day
Conventional	15	97.56 ± 2.97	98.22 ± 3.86
	60	101.30 ± 2.12	99.03 ± 1.88
	100	100.85 ± 1.46	101.24 ± 1.90

96-Microwell plate	15	98.01 ± 2.15	100.31 ± 1.91
	60	101.72 ± 0.98	100.24 ± 1.08
	100	100.10 ± 0.71	100.36 ± 0.84
		Inter-day
Conventional	15	97.25 ± 3.83	98.35 ± 3.94
	60	101.10 ± 2.14	99.15 ± 2.31
	100	101.31 ± 1.60	100.17 ± 1.80

96-Microwell plate	15	97.86 ± 1.87	100.71 ± 2.08
	60	101.10 ± 1.16	100.34 ± 1.26
	100	100.81 ± 0.85	100.15 ± 0.91