DEVELOPMENT OF A SAMPLE PREPARATION PROCEDURE OF BIOLOGICAL FLUIDS BY SOLID-PHASE EXTRACTION OF PYRROLIDINOPHENONE DERIVATIVES

Abstract

The topical issue of forensic toxicology is the development of sample preparation procedures that provide a high level of selectivity and evidence of the results by gas chromatography-mass spectrometric analysis (GC-MS) with a quadrupole detector. The aim of the study is to develop a technique for sample preparation of biological fluids by solid-phase extraction (SPE) using a model compound phenylpiracetam and to measure its metrological characteristics. Materials and methods. The objects of the study were model samples of biological fluids (blood and urine) with a phenylpiracetam concentration of 20.0-6000.0 ng / ml. The SPE procedure was developed by modifying the separation technique on mixed-type sorbents used in routine practice for screening studies for drugs, including pyrrolidinophenone derivatives. Isopropyl alcohol was used as an eluent for desorption of phenylpiracetam from the molecularly imprinted sorbent. Results. Comparison of the average recovery of phenylpiracetam (for concentration range of 20.0-6000.0 ng / ml) from aqueous solutions, blood and urine samples shows that the recovery from model blood samples is 6% lower than the recovery from aqueous solutions and 4% lower compared to urine samples. The relative errors in determining the degree of extraction from blood samples used to assess the correctness of the sample preparation procedure did not exceed ± 12% for all levels of 20  Евразийский Союз Ученых (ЕСУ) #12(81), 2020

phenylpiracetam concentrations. For the upper concentration level (1500.0 ng / ml), the error is ± 11.5%. The minimum value was observed at an average concentration level of 500.0 ng / ml and amounted to ± 5.3%. The relative errors in determining the degree of extraction from urine samples for all concentration levels did not exceed ± 6%. For the upper concentration level (1500.0 ng / ml), the error is about ± 4%. The precision of the results of phenylpiracetam determining recovery from model blood samples at the lower level of concentrations was 16.1%, at the upper level of concentrations - 6.1%. For urine samples, the precision of the recovery at the lower concentration level was 12.6%, at the upper concentration level - about 5%.