Development of a HPLC-UV method for the quantitative determination of four short-chain fatty acids and lactic acid produced by intestinal bacteria during in vitro fermentation

J Pharm Biomed Anal. 2013 Jun;80:107-15. doi: 10.1016/j.jpba.2013.02.032. Epub 2013 Feb 28.

Abstract

A rapid and sensitive HPLC-UV method for the quantitative determination of four short-chain fatty acids (SCFAs) and lactic acid (LA) produced during in vitro fermentation is presented. Extraction of SCFAs from supernatants of bacterial cultures is aggravated due to their polarity and volatility. Detection can only be performed at a short, non-selective UV wavelength (210nm), due to the lack of any significant chromophore. Therefore special attention was paid to the optimization of the sample preparation procedure and the HPLC-UV conditions. The final extraction procedure consisted of a liquid-liquid back extraction using diethylether. Prior to HPLC-UV analysis the samples were acidified (pH<2) in order to improve retention of the SCFA's and LA on the Hypersil Gold aQ column. Matrix-matched calibration graphs were prepared for all analytes of interest (range 0.5-50mM) and correlation and goodness-of-fit coefficients were between 0.9951-0.9993 and 3.88-8.27%, respectively. Limits of detection and quantification ranged from 0.13 to 0.33mM and 0.5 to 1.0mM, respectively. The results for the within-day and between-day precision and accuracy fell within the ranges specified. The reported validated method has been successfully used for the in vitro screening of supernatants of bacterial cultures for the presence of butyric acid, aiming to select for butyric acid-producing bacteria. In addition, the method has been used to determine the production pattern of selected fatty acids by bacterial species isolated from human feces and chicken caeca.

Publication types

  • Validation Study

MeSH terms

  • Animals
  • Bacteria / isolation & purification
  • Bacteria / metabolism*
  • Calibration
  • Cecum / microbiology
  • Chickens
  • Chromatography, High Pressure Liquid / methods*
  • Fatty Acids, Volatile / analysis*
  • Fatty Acids, Volatile / metabolism
  • Feces / microbiology
  • Fermentation
  • Humans
  • Hydrogen-Ion Concentration
  • Lactic Acid / analysis*
  • Lactic Acid / metabolism
  • Limit of Detection
  • Sensitivity and Specificity
  • Time Factors

Substances

  • Fatty Acids, Volatile
  • Lactic Acid