Abstract:
This study presents a reliable method for the quantification of metabolite concentrations in follicular fluid with the high-resolution magic angle spinning nuclear magnetic resonance (HR-MAS NMR) spectroscopy and the ERETIC2 (Electronic REference To access In vivo Concentrations) based on PULCON (pulse length based concentration determination) principle. The positive effect of the HR-MAS probe technology on spectral quality and its ability to perform analyses with very low sample amounts were the most important factors of proposing this method. In evaluating the performance of the proposed method, standard creatine solutions in different concentrations containing DSS (2,2-dimethyl-2-silapentane-5-sulfonate sodium salt) as an internal reference standard were analyzed using different pulse programs (cpmgpr1d and zg30). The results obtained with the ERETIC2 were compared with the classical internal standard NMR quantification method (DSS method). The relative standard deviation (RSD) values for ERETIC2 were in the range of 0.3%-5.7% and recovery values were calculated as minimum 90.3%, while RSD values for DSS method were in the range of 0.1%-3.1% and recovery values were minimum 97.0%. Besides, it was observed that the metabolite concentration values calculated using the ERETIC2 procedure of follicular fluid samples obtained from the women with endometriosis and healthy controls were compatible with the values those obtained using different methodologies. The obtained results showed that the proposed quantification method based on the HR-MAS spectroscopy can easily be used in biological fluids and therefore it can be utilized as a good alternative to the internal standard method considering its accuracy and precision. © 2022, Turkish Chemical Society. All rights reserved.