Determination of opiates in hair by capillary electrophores (CE)

Author(s)

Elizabete Campos de Lima

• Document type: Doctoral Thesis
• Press: São Paulo. , gráficos, ilustrações, tabelas.
• Institution: Universidade de São Paulo (USP). Conjunto das Químicas (IQ e FCF) (CQ/DBDCQ)
• Defense date: 2003-04-25

Examining board members

Marina Franco Maggi Tavares; Pierina Sueli Bonato; Alice Aparecida da Matta Chasin; Erika Rosa Maria Kedor; Regina Lucia de Moraes Moreau

• Advisor: Marina Franco Maggi Tavares
• Field of knowledge: Physical Sciences and Mathematics - Chemistry
• Indexed in: Banco de Dados Bibliográficos da USP-DEDALUS
• Location: Universidade de São Paulo. Biblioteca do Conjunto das Químicas; CQ T/543.0871; L732d

Abstract

This work describes a series of studies aiming at the determination of opiates of clinical and forense importance using hair as an alternative biological matrix and capillary electrophoresis (CE) as the technique of choice. Electrolyte compositions were criteriously explored using CE in its diverse modes of operation and the separation of 15 opiates and metabolites (petidine, morphine, tramadol, naloxone, phentanyl citrate, alphentanil HCl, suphentanyl citrate, 6-acetylmorphine, pentazocine, nalorphine, codeine, 6-acetylcodeine, methadone, morphine-3&#946;-D-glucuronide, norphentanyl) was accomplished in less than 14 min using as electrolyte, phosphate buffer 60 mmol/L, pH 2.5 with 8 mmol/L &#946;-ciclodextrine and 8 % methanol in the conditions: inj. 5 s/10 kV, 30 kV during analysis, detection 200nm and 20 &#176;C. Additionally, a comparative evaluation of the strategies for hair extraction and pre-concentration of opiates to contemplate the concentration sensitivity restrains of capillary electrophoresis have been investigated. Recoveries of target analytes (petidine, naloxone, tramadol, fentanyl, alfentanyl and sufentanyl) using liquid-Iiquid extraction and solid-phase extraction employing a variety of solvents and stationary phases were estimated. A novel, simple and reliable strategy for digestion and extraction of morphine in hair was developed based upon acidic hydrolysis (45°C, 12 h) followed by solid-phase extraction in ion-exchange resin cartridges (MCX, Supelco). Recoveries of morphine up to 81.4% were obtained with this procedure. Hair extraets were analyzed via CE using 20 mmol/L phosphate buffer at pH 2.5, electrokinetie injection (5 kV, 5 s), 25 kV applied voltage, detection at 200 nm in a eapillary with dimensions 75 &#181;m i.d., 47 em totallength and 40 em effective length. lhe methodology was validated with respect to precision (CV < 20 %), aecuraey (relative error < 20 %), linearity (r > 0.99), limit of detection and quantifieation, 0.064 mg/L (0.12 ng of morphine per mg of hair) and 0.214 mg/L (0.37 ng of morphine per mg of hair), respectively, with appropriate selectivity and specificity, tested for four major interfering eompounds (morphine-3&#946;D-glucuronide, nalorphine, clonidine and codeine). Hair analyses of over 100 samples from c.a. 35 patients (Grupo da Dor, Hospital das Clínicas, Universidade de São Paulo, HC-FMUSP) suffering from radieular or medullar lesion, receiving morphine by implantable intrathecal systems were eondueted. Levels of morphine in the patients hair was found in the range of 1.3-18.4 ng/mg. (AU)