Indirect determination of isonicotinylhydrazine by atomic absorption spectrophotometry
1973 Volume 22 Issue 7 Pages 896-899
Details
1973 Volume 22 Issue 7 Pages 896-899
Isonicotinylhydrazine (INAH) reacts with cupric ion to produce INAH-Cu(II) chelate (2: 1) at pH 4.5, which can be extracted with methyl isobutyl ketone (MIBK). Therefore, it is found that INAH can be quantitatively determined indirectly, if the quantity of Cu(II) in the organic phase is measured by atomic absorption spectrophotometry.
Measurements are carried out with a Hitachi 207 atomic absorption spectrophotometer.
The optimum working conditions for atomic absorption spectrophotometry are as follows: wavelength, 3247 Å; lamp current of hollow cathode lamp for Cu, 15 mA; slit width, 0.18 mm; air flow rate, 16.0l/min, and acetylene flow rate, 3.0 l/min.
As a higher absorbance ratio was obtained in the range of pH 4.04.8, buffer solution at pH 4.5 was used in this measurement.
Procedure for the determination was as follows; cupric chloride solution and aqueous INAH solution were mixed together with acetic acid-sodium acetate buffer solution which was adjusted to pH 4.5, and this solution was extracted with MIBK for 15 minutes twice, and it was kept standing for 10 minutes.
The organic phase was centrifuged at 3000 rpm for 5 minutes, and the copper in organic phase was measured by atomic absorption spectrophotometer.
The concentration of cupric chloride solution was 3 times more than that of INAH solution and the shaking time was at least for 10 minutes. The species extracted in MIBK layer showed the composition of INAH-Cu(II) to be 2: 1, which was determined by continuous variation method.
The working curve for the MIBK extracts showed a good linearity over the range of 0.2×10-41.7×10-4 M INAH. The relative standard deviation of this method was calculated to be 0.44%, and the recovery of copper by the back-extraction with 1 N HCl was 98.5%.
It was shown that this method might be applicable to the determination of INAH in the preparations, for no effect of the vehicles, such as soluble starch, gentiana powder, magnesium stearate and sodium benzoate, on the absorbance ratio was observed.
