Spectrophotometric Determination of Iron(II) and Cobalt(II) by Direct, Derivative, and Simultaneous Methods Using 2-Hydroxy-1-Naphthaldehyde-p-Hydroxybenzoichydrazone

Table 14

Linear regression analysis of the determination of Fe(II) and Co(II) in mixture by second derivative spectrophotometry.

Metal ion determined	Wave length (nm)	Other metal present (μg mL^−1)		Slope	Intercept	Correlation coefficient
		Fe(II)	Co(II)
Fe(II)	436			3.9×10^−3	2.4×10^−4	0.9994
			0.589	3.2×10^−3	1.9×10^−4	0.9995
Co(II)	426			1.4×10^−4	2.3×10^−6	0.9999
		0.33		1.4×10^−4	2.0×10^−6	0.9998