Gilmare Antônia da Silva
Federal University of Ouro Preto, Brazil
Title: Chemometric approach to optimize the operational parameters of ESI for the determination of contaminants of emerging concern in aqueous matrices by LC-IT-TOF-HRMS
Biography
Biography: Gilmare Antônia da Silva
Abstract
Contaminants of emerging concern are organic compounds used in large quantities by the society for various purposes. They have shown biological activity at low concentrations and the difficulty to detect and quantify them in the environment stimulates the development of appropriate analytical methods. In this work, a chemometric approach to positive and negative ESI optimization for the simultaneous determination of contaminants of emerging concern in water samples by LC-IT-TOF-HRMS was applied. Three types of phase modifiers were used: formic acid, ammonium hydroxide and formic acid/ammonium formate. The effects of the operational parameters mobile phase modifier concentrations, mobile phase flow rate, heating block temperature and drying gas flow rate were evaluated by the 24−1 fractional factorial and Doehlert experimental designs. Factorial design indicated that ammonium hydroxide was more efficient compared to the other evaluated modifiers (higher ion intensities). Doehlert design allowed finding a region indicative of the optimum experimental conditions for most analytes. The best experimental condition observed was 3.5 mM ammonium hydroxide concentration; 0.0917 mL/min of mobile phase; 300 ºC heating block temperature; and drying gas at 200 kPa. These optimized parameters resulted in decreased detection limits of the method. The optimized method was applied to the evaluation of water samples coming from the Rio Doce basin - Minas Gerais/Brazil utilizing principal component analysis and Kohonen neural network. In this way, the use of chemometric approaches showed to be a promising way to optimize the simultaneous determination of 21 contaminants of emerging concern in water by LC-IT-TOF-HRMS using ESI. Biography