Reverse flow injection spectrophotometric determination of ciprofloxacin in pharmaceuticals using iron from soil as a green reagent

A novel reverse flow injection spectrophotometric method for the determination of ciprofloxacin was successfully combined with the on-line introduction of an iron solution extracted from soil as green reagent. The assay was optimized by a univariate method to select the optimum conditions for the highest absorbance and highest stability of the complex. Beer-Lambert's law (lambda(max) = 440 nm) is obeyed in the range 0.5-50 mu g mL(-1) with a correlation coefficient (r(2)) of 0.9976 and 0.9996 using soil as green reagent from Khon Kaen, Thailand and Vientiane, Laos, respectively. The average percentage recoveries were in the range of 98.55-102.14% and the precision was in the range of 0.80-1.73%. The limit of detection and the limit of quantitation were 020 and 0.69 mu g mL(-1), respectively, with a sampling rate of over 46 samples h(-1). The method was successfully applied to the determination of ciprofloxacin in commercial pharmaceutical formulations. The results were in good agreement with those obtained by the reference HPLC method using a t-test at 95% of confidence level for comparison. This method is suitable for laboratories looking for alternative analytical methods using green reagents. (C) 2017 Elsevier B.V. All rights reserved.