Quantitative determination of faecal fatty acids and triglycerides by Fourier transform infrared analysis with a sodium chloride transmission flow cell

We studied the applicability of Fourier transform infrared (FTIR) spectroscopy to determine the amount of faecal fatty acids and triglycerides in faeces. For this, we have optimised a simple hexane extraction procedure of stool. After extraction, an aliquot of the hexane layer is directly injected into the measurement cell of the spectrophotometer and absorbance at 1714 cm(-1) and 1751 cm(-1) is read for quantitation of fatty acids and triglycerides, respectively. Comparison of the FTIR spectrophotometric method with the traditional titrimetric Van de Kamer method for faecal fat determination showed a good correlation. The advantage of our method over the previously described FTIR and nearinfrared spectroscopy (NIR) methods is that it allows a combined measurement of both fatty acids and triglycerides in one run, using a simple and rapid hexane extraction procedure. Clinical validation of this method was performed by reviewing the medical records of 24 patients with steatorrhoea: patients with pancreatic steatorrhoea showed highly increased faecal triglyceride excretion, but a normal faecal fatty acid and faecal weight when compared with patients with nonpancreatic intestinal steatorrhoea.