TITLE:
Spectrophotometric Method for Determination of Chromium Ion in Aqueous Solution Using Ninhydrin
AUTHORS:
Hutaf Mustafa Baker, Tiba Dheyaa Rahoomi, Hamzeh Abdel-Halim
KEYWORDS:
Ninhydrin, Chromium Ions, Spectroscopy, Stoichiometry
JOURNAL NAME:
American Journal of Analytical Chemistry,
Vol.13 No.10,
October
31,
2022
ABSTRACT: A simple, precise, inexpensive and reproducible spectrophotometric method was investigated for the determination of chromium ion (III) in aqueous media, this method based on the formation of a complex between chromium ion (III) and ninhydrin, a deep greenish-violet colored product in the presence of potassium hydroxide was obtained. The absorption of this product was measured at λmax = 375 nm. The reaction proceeds quantitatively at room temperature. The linear calibration curve was constructed over range of (4.8 × 10-4 - 1.6 × 10-2) mol/L of chromium ions with molar absorptivity of 2.90 × 102 and correlation coefficient R2 = 0.9989. The calculated Sandell’s sensitivity value is 0.179 μg/cm2, the limits of detection (LOD) and the limit of quantification (LOQ) are found to be 3.74 × 10-5 and 1.24 × 10-4 mol/L, respectively. The method was successfully applied for determination of the chromium ion in aqueous solution. The stoichiometry of the reactions was determined molar combining ratio of 1:2 between chromium and ninhydrin.