Method Development for the Analysis of Fatty Acids in Adipose Tissue Using Stir Bar Sorptive Extraction Coupled with Gas Chromatography-Mass Spectrometry
The project was aimed to develop an easy and sensitive analytical tool to study the role of fatty acids (FAs) profile in periprostatic adipose tissue (PPAT) and prostate cancer (PCa). PCa is the second leading cause of cancer-related death among American men. Although obesity has been mostly ruled out by many researchers as a risk factor for developing PCa, it has shown to be associated with PCa metastasis and progression. Periprostatic adipose tissue, which was present on 48% of prostatic surfaces, has been reported to act as energy sources for facilitating a positive microenvironment for PCa tumor progression. To understand the role of PPAT fatty acid profile in relationship to PCa aggressiveness, this project was set out to develop a green method to analyze the fatty acids (FAs) in adipose tissue using a solvent-less sample preparation technique, known as stir-bar sorptive extraction, coupled with thermal desorption-Gas Chromatography/Mass Spectrometry. To detect FAs by Gas Chromatography-Mass Spectrometry, we used pork fat as the model adipose tissue. FAs in pork fat were first subjected to transesterification. Several conditions to optimize the transesterification process such as time, temperature, and acid amount in the solvent mixture were studied. The best transesterification condition was found to be at 60-70 oC (regardless of the heating methods, either in an oven or sonicator), with the reaction time of 1hr and using a solvent mixture of CH3OH:HCl:CHCl3 (10:3:1, v/v/v). After transesterification, fatty acid methyl esters (FAMEs) were extracted by stir bar sorptive extraction (SBSE). We studied factors that could promote the extraction efficiency of FAMEs by SBSE. These factors included stirring time, solvent addition, and stirring speed. We found that 1hr at 1500 RPM and no solvent addition would give the best extraction efficiency of FAMEs. By estimate, the concentrations of FAMEs detected in the fat samples ranged from 0.18 ppb (µg/L) to 114.82 ppb (µg/L). Therefore, the limit of detection for our method could be below 0.18 ppb (µg/L) for various FAMEs in fat tissue. The sample preparation developed in this report has provided a green and sensitive alternative for the study of FAs in adipose tissue, which will provide a valuable tool for future studies in the FAs profile in PPAT and its impacts on PCa progression.
Encerrado Manriquez, Angela Marisol, "Method Development for the Analysis of Fatty Acids in Adipose Tissue Using Stir Bar Sorptive Extraction Coupled with Gas Chromatography-Mass Spectrometry" (2020). ETD Collection for University of Texas, El Paso. AAI28090829.