Automation of solid phase extraction for preconcentration of steroid hormones in a sequential injection system

ÁVILA OROZCO, FRANCISCO; HORSTKOTTE, BURKHARD; CHOCHOLOUS, PETR; ACEBAL, CAROLINA C.; FERNANDEZ BAND, BEATRIZ S.; SKLENÁROVÁ, HANA; SOLICH, PETR

Praga

Conferencia; Flow Analysis XIII; 2015

The presence synthetic estrogen and progestogens in hormonal contraceptives tablets of low dosage has presented a challenging analytical problem [1,2]. The aim of this work was to develop an automated solid phase extraction (SPE) method for determination of two hormones used for contraceptive purpose: Ethinyl Estradiol (EE) and Norethisterone (NOR) in a sequential injection (SIA) system with spectrophotometric detection at 216 and 281 nm respectively. A minicolumn, packed with Oasis® HLB, a copolymer of hydrophilic-lipophilic balanced, was used as sorbent and coupled on-line to the SIA system. Experimental variables were optimized to achieve the best conditions for automation of SPE procedure. Two column lengths (1.0 cm, 2.0 cm) were tested and the best results, were obtained with the 1.0 cm column. Different volumes (50-600 µL) of pure organic solvents (MeOH, ACN) and their mixtures with water in different ratios were tested for elution step and 500 µL of pure MeOH was used for eluting both analytes. Elution flow-rate (7.0 µL s-1) was optimized in the range of 5.0-15.0 µL s-1. Sample volume optimization was carried out in the range of 300-900 µL. The method was linear in the range between 10.2 - 5100.0 mg L-1, for both analytes using a ratio 900:500 µL of sample:eluent. [1] J. Aufartová, C. Mahugo-Santana, Z. Sosa-Ferrera, J. Santana-Rodríguez, L. Nováková, P. Solich, Analytica Chimica Acta 704 (2011) 33.[2] F. Guo, Q. Liu, G. Qu, S. Song, Ji. Sun, J. Shi, G. Jiang, Journal of Chromatography A, 1281 (2013) 9.