International Journal of Analytical Chemistry / 2012 / Article / Tab 11 / Research Article
Spectrophotometric Determination of Iron(II) and Cobalt(II) by Direct, Derivative, and Simultaneous Methods Using 2-Hydroxy-1-Naphthaldehyde-p-Hydroxybenzoichydrazone Table 11 Analytical characteristics of [Co(II)-HNAHBH].
Parameter Direct method Second derivative Third derivative 425 nm 431 nm 443 nm 437 nm 449 nm Beer’s law range (μ g mL−1 ) 0.118–3.534 0.059–4.712 0.059–4.712 0.059–1.380 0.056–1.380 Molar absorptivity, (L mol−1 cm−1 )
— — — — Sandell’s sensitivity, μ g cm−2 0.003 — — — — Angular coefficient (m) 0.375 0.0003 0.093 0.0002 0.009 Y-intercept (b) 0.0197
Correlation coefficient 0.9999 0.999 0.9999 0.9999 0.9999 RSD (%) 1.37 1.84 4.3 1.15 7.6 Detection limit (μ g mL−1 ) 0.04 0.06 0.13 0.04 0.21 Determination limit, (μ g mL−1 ) 0.124 0.18 0.39 0.114 0.65 Composition (M : L) 2 : 3 — — — Stability constant
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