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Molecules

Title:		An Optimization of Liquid-Liquid Extraction of Urinary Volatile and Semi-Volatile Compounds and Its Application for Gas Chromatography-Mass Spectrometry and Proton Nuclear Magnetic Resonance Spectroscopy
Author(s):		Drabinska N; Mlynarz P; de Lacy Costello B; Jones P; Mielko K; Mielnik J; Persad R; Ratcliffe NM;
Address:		"Institute of Animal Reproduction and Food Research of Polish Academy of Sciences, 10 Tuwima Str., 10-748 Olsztyn, Poland. Institute of Biosensor Technology, University of the West of England, Coldharbour Lane, Frenchay, Bristol BS16 1QY, UK. Department of Biochemistry, Molecular Biology and Biotechnology, Faculty of Chemistry, Wroclaw University of Science and Technology, 27 Wybrzeze Stanislawa Wyspianskiego, 50-370 Wroclaw, Poland. Indigo Science Ltd., Bristol BS7 9JS, UK. Bristol Urological Institute, Southmead Hospital, Bristol BS10 5BN, UK"
Journal Title:		Molecules
Year:		2020
Volume:		20200811
Issue:		16
Page Number:		-
DOI:		10.3390/molecules25163651
ISSN/ISBN:		1420-3049 (Electronic) 1420-3049 (Linking)
Abstract:		"Urinary volatile compounds (VCs) have been recently assessed for disease diagnoses. They belong to very diverse chemical classes, and they are characterized by different volatilities, polarities and concentrations, complicating their analysis via a single analytical procedure. There remains a need for better, lower-cost methods for VC biomarker discovery. Thus, there is a strong need for alternative methods, enabling the detection of a broader range of VCs. Therefore, the main aim of this study was to optimize a simple and reliable liquid-liquid extraction (LLE) procedure for the analysis of VCs in urine using gas chromatography-mass spectrometry (GC-MS), in order to obtain the maximum number of responses. Extraction parameters such as pH, type of solvent and ionic strength were optimized. Moreover, the same extracts were analyzed using Proton Nuclear Magnetic Resonance Spectroscopy ((1)H-NMR), to evaluate the applicability of a single urine extraction for multiplatform purposes. After the evaluation of experimental conditions, an LLE protocol using 2 mL of urine in the presence of 2 mL of 1 M sulfuric acid and sodium sulphate extracted with dichloromethane was found to be optimal. The optimized method was validated with the external standards and was found to be precise and linear, and allowed for detection of >400 peaks in a single run present in at least 50% of six samples-considerably more than the number of peaks detected by solid-phase microextracton fiber pre-concentration-GC-MS (328 +/- 6 vs. 234 +/- 4). (1)H-NMR spectroscopy of the polar and non-polar extracts extended the range to >40 more (mainly low volatility compounds) metabolites (non-destructively), the majority of which were different from GC-MS. The more peaks detectable, the greater the opportunity of assessing a fingerprint of several compounds to aid biomarker discovery. In summary, we have successfully demonstrated the potential of LLE as a cheap and simple alternative for the analysis of VCs in urine, and for the first time the applicability of a single urine solvent extraction procedure for detecting a wide range of analytes using both GC-MS and (1)H-NMR analysis to enhance putative biomarker detection. The proposed method will simplify the transport between laboratories and storage of samples, as compared to intact urine samples"
Keywords:		Female Gas Chromatography-Mass Spectrometry/*methods Humans Liquid-Liquid Extraction/*methods/*standards Proton Magnetic Resonance Spectroscopy/*methods Urinalysis/*methods Volatile Organic Compounds/*urine 1h-nmr Gc-ms liquid-liquid extraction method opt;
Notes:		"MedlineDrabinska, Natalia Mlynarz, Piotr de Lacy Costello, Ben Jones, Peter Mielko, Karolina Mielnik, Justyna Persad, Raj Ratcliffe, Norman Mark eng GA2543/Above and Beyond Charity in Bristol/ Switzerland 2020/08/17 Molecules. 2020 Aug 11; 25(16):3651. doi: 10.3390/molecules25163651"