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

Table 8

Determination of cobalt in surface soil samples.

Sample and source		Cobalt (μg mL^−1)
		Present method*	Reference method; [23]
S1	Agricultural land; (red soil Anantapur.)	16.48±0.030	17.20±0.024
S2	Agricultural land (black soil, Tadipatri.)	24.15±0.026	23.68±0.022
S3	Riverbed soil (Tungabhadra river, Kurnool)	14.68±0.034	15.26±0.018
S4	Industrial soil (electroplating industry, Anantapur)	118.40±0.042	122.12±0.029

*Average of four determinations.