Methods for determination of pharmaceuticals, their metabolites and endocrine disruptors in surface water using separation techniques in liquid media (CE/UV, CE-MS, HPLC-MS/MS)

Author(s)

Ana Carolina de Oliveira Costa

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Conjunto das Químicas (IQ e FCF) (CQ/DBDCQ)
• Defense date: 2009-12-03

Examining board members

Marina Franco Maggi Tavares; Jose Eduardo Bevilacqua; Emanuel Carrilho; Claudimir Lucio do Lago; Pedro Vitoriano de Oliveira

• Advisor: Marina Franco Maggi Tavares

Abstract

This work presents the development and validation of analytical methods to investigate the presence of pharmaceutical compounds, their metabolites and endocrine disruptors in surface water using on line (stacking) and off line (solid phase extraction) sample clean up and enrichment strategies coupled to advanced separation techniques in liquid medium (capillary electrophoresis and liquid chromatography with UV detection and their hyphenation with mass spectrometry). In the first Chapter, general aspects on pharmaceuticals, products of personal care and endocrine disruptors are discussed as well as their origin and means of entry to the environment. Chapter 2 describes the development of a separation method for the determination of eight pharmaceuticals and endocrine disruptors substances with acidic character (diclofenac, bezafibrate, fenoprofen, ibuprofen, ketoprofen, naproxen, gentisic and salicylic acids) in a single run using capillary electrophoresis with on line sample enrichment (analyte stacking with large sample volume injection) in electrolytes composed of 30 mmol L-1 sodium tetraborate at pH 9.3 and 5 mmol L-1 Brij 35. The proposed method reached limits of detection between 2 µg L-1 (naproxen) and 80 µg mL-1 (ibuprofen). In Chapter 3, a CE separation method for the determination of nine pharmaceuticals and hormones with neutral and basic character (fluoxetin, trimethoprim, diazepam, carbamazepine, propranolol, clofibrate, fenofibrate, ethynylestradiol and estrone) was exploited. As preconcentration strategy, micelle stacking with large sample volume injection was performed. Limits of detection in the order of 9 µg L-1 were reached with electrolytes composed of 30 mmol L-1 phosphoric acid, 40 mmol L-1 sodium dodecylsulfate, 20% (v,v) acetonitrile and 0.1% (v,v) triethylamine. In Chapter 4, the physicochemical parameters associated with the solid phase extraction technique, such as sorbent type, breakthrough volume, elution volume, extraction cartridge rinse, among others, were evaluated. Optimum sample clean up and off line preconcentration conditions combined with the optimum on line preconcentration and separation conditions described in Chapters 2 and 3, for all substances under consideration, were applied to the analysis of real surface water samples collected at the Reservoir Billings (Sao Paulo state, Brazil). The combined method reached concentrations in the order of 500 ng L-1, with satisfactory recoveries (58 88%) for complex environmental matrices. In Chapter 5, a method for the analysis of alkyl p-hydroxybenzoates, substances used as preservatives in several products of personal care, was developed using capillary electrophoresis associated with on line (stacking with large volume injection) and off line (SPE) preconcentration strategies. The proposed method, which used 40 mmol L-1 glycine and 40 mmol L-1 triethylamine as electrolyte, was applied to the analysis of alkyl p-hydroxybenzoates in surface water, reaching 4 - 6 µg L-1 concentrations. Chapter 6 describes the development of a CE method for de analysis of linear alkylbenzene sulfonates (LAS) and homologues, surfactants commonly used in the composition of detergents of industrial and domestic use. As separation electrolyte, 60 mmol L-1 TRIS, 30 mmol L-1 HIBA, 15 mmol L-1 Brij 35 and 40% (v,v) acetonitrile was used. A solid phase preconcentration extraction step in C18 was employed and a total LAS concentration of 1.09 mg L-1 was found in a sample obtained from the effluent of a sewage treatment plant. In Chapter 7, a CE-MS (ion trap) method was developed for the analysis of cimetidine, propranolol, salbutamol, trimethoprim and methoclopramide in fortified surface water samples collected in the Reservoir Billings (Sao Paulo state, Brazil) and previously enriched by SPE (PS-DVB). The method reached concentrations of c.a. 40 µg L-1. Finally, in Chapter 8, a method based on high-performance liquid chromatography coupled with two different mass spectrometers: a triple quadrupole and a triple quadrupole with linear ion trap). Several pharmaceuticals were investigated in surface water samples collected from the Reservoir Billings (Sao Paulo state, Brazil). With the LC-MS/MS (triple quadrupole) system, carbamazepine was found in a non treated sample (just a filtration step prior to injection was performed) in a concentration level of 20 ng L-1. It is worth mentioning that for carbamazepine, a LOD of 400 fg L-1 was found, without any preconcentration sample treatment (AU)