Table 1.

The Regression parameters and validation results for determining IND and MOM by the proposed methods

Parameter	IPC method		Spectroscopic methods
			First derivative (1D)		Ratio derivative (RD)
	MOM	IND	MOM	IND	MOM	IND
Wavelength (nm)	259	259	275.67	251.62	280.64	310.49
Linearity range (µg mL−1)	0.1–10	0.1–10	1.1–32	1–30	1.1–32	1–30
Slope	62.347	55.128	− 0.007	0.01	0.065	0.083
Intercept	4.120	36.436	− 0.016	0.013	0.024	− 0.017
correlation coefficients (r)	0.9997	0.9998	0.9996	0.9998	0.9998	0.9999
Accuracy (%R)	99.97	99.91	100.02	99.69	100.28	100.11
Precision (%RSD)
Repeatabilitya	0.531	0.832	0.366	0.774	0.682	0.755
Intermediate precisionb	0.732	0.965	0.348	0.675	0.985	0.857
LOD (μg/mL)	0.026	0.031	0.290	0.314	0.202	0.227
LOQ (μg/mL)	0.079	0.094	0.879	0.951	0.612	0.688
Sy/x	0.965	1.012	9.1 × 10–4	1.2 × 10–5	5.6 × 10–4	8.12 × 10–4
Sa	0.5	0.52	2.0 × 10–5	5.00 × 10–4	1.0 × 10–5	0.01
Sb	0.099	0.103	4.0 × 10–5	5.00 × 10–5	2.2 × 10–5	3.4 × 10–5
% RSDc	1.334	0.677	0.737	0.629	0.556	0.97
% Errord	0.471	0.239	0.301	0.257	0.227	0.395
Robustnesse (%RSD)	0.317	0.586	0.432	0.602	0.552	0.499

^aThe intraday (n = 3), average of three responses of three different concentrations repeated three times on the same day

^bThe interday (n = 3), average of three responses of different three concentrations repeated three times at three successive days

^cPercentage relative standard deviation(SD × 100/mean %R)

^dPercentage relative error. = % RSD/$\sqrt{n}$

^eAverage of three determinations