Plackett-Burman Factorial Design for the Optimization of a Spectrophotometric Flow Injection Method for Phenol Determination in Tap and Bottled Water Using 4-Aminoantipyrine

Abstract

<p>Plackett-Burman and Quarter fraction 2<sup>5-2</sup> factorial designs were applied to evaluate a spectrophotometric flow injection method in order to determine phenol in water by using 4-aminoantipyrine (4-aap) as derivatizing reagent. With a minimum number of experiments, the designs enabled the best conditions for phenol analysis: 80 cm and 180 cm reactors; flow-rates being: NH<sub>3</sub> 1.0 mL min<sup>-1</sup>; 4-aap 0.35 mL min<sup>-1</sup> and K<sub>3</sub>[Fe(CN)<sub>6</sub>] 0.35 mL min<sup>-1</sup>, [NH<sub>3</sub>] 0.064 mol L<sup>-1</sup>, [4-aap] 9.84 × 10−3 mol L<sup>-1</sup>, [K<sub>3</sub>[Fe(CN)<sub>6</sub>]] 0.02 mol L<sup>-1</sup>, and an injection volume of 200 μL. With the optimized method it was possible to increase the lineal range from 0.3 μg mL<sup>-1</sup> to 30 μg mL<sup>-1</sup> and also to quantify the maximum allowable phenol concentration in water in comparison with other standard and flow injection methods whose lineal range are from 0.5 μg mL<sup>-1</sup> to 20 μg mL<sup>-1</sup> and from 0.5 μg mL<sup>-1</sup> to 16 μg mL<sup>-1</sup>, respectively. The detection limit was of 0.13 μg mL<sup>-1</sup> and the regression coefficient was of 0.9999, making possible a throughput of 36 determinations an hour with a minimum consume of reagent. With the proposed method, a distillation step was not necessary to remove sulfates but, when the sulfate:phenol ratio was higher than 83, the analytical signal for phenol increased 8%, but hypochlorite interfered with the signal when the ypochlorite:phenol ratio was higher than 1.</p>

Optimization of Nitrosation Reaction for Synthesis of 4-Aminoantipyrine by Response Surface Methodology and Its Reaction Mechanism

“…6 They can form complexes with various metal ions such as La 3+ , Pr 3+ , Nd 3+ , and Sm 3+ . Dozens of AA reagents have been synthesized, 7 and most of them are used as reagents for spectroscopic analysis, including polarimetry, 8 synchrotron analysis, 9 flow injection analysis, 10 and so forth. Several AA derivatives are also universally used in clinics, having biological functions and pharmaceutical values such as antibacterial 11 and antipulmonary tumor.…”