NMR spectrometry

Abstract

In the present investigation, suitability of nuclear magnetic resonance (NMR) spectrometry for total stool fat quantification in patients with normal or impaired exocrine pancreatic function (chronic pancreatitis) has been analyzed in comparison with a conventional chloroform-methanol extraction technique. Basic temperature-dependence studies of NMR spectrometry (90 degrees/180 degrees radiofrequency pulse sequence) on 21 chloroform-methanol extracted pure total stool lipid standards (weight range: 0.05-1.6 g) revealed significantly (P less than 0.05) improving correlations between NMR signal amplitudes and corresponding weights at increasing temperatures (r = 0.952/40 degrees C, r = 0.965/60 degrees C, r = 0.988/80 degrees C), thus indicating 80 degrees C as optimal temperature for NMR spectrometric total stool fat quantification. In subsequent comparative measurements of lyophilized stool samples, NMR spectrometry (at 80 degrees C) and conventional chloroform-methanol extraction provided significantly (P less than 0.001) correlated results with respect to total fecal fat contents/day of quantitatively collected and homogenized stools in 93 patients with known exocrine pancreatic function (secretin-pancreozymin test), irrespective of whether correlations were determined for all 93 patients (r = 0.983) or separately for patients with normal (N = 45; r = 0.867), moderately reduced (N = 31; r = 0.946), or highly reduced (N = 17; r = 0.992) exocrine pancreatic function and correspondingly increased total fecal fat excretions.

Species Variation in the Fecal Metabolome Gives Insight into Differential Gastrointestinal Function

“…Metabolite assignments were made by reference to the literature [21][22][23][24][25][26] and by using statistical total correlation spectroscopy (STOCSY) with an in-house-developed script (Dr. O. Cloarec, Imperial College London). 27 Assignments were confirmed with standard two-dimensional (2-D) 1 H-1 H correlation spectroscopy (COSY), total correlation spectroscopy (TOCSY), 1 H- 13 C heteronuclear single quantum correlation (HSQC), and heteronuclear multiple bond correlation (HMBC), performed on selected samples.…”

Fat Malabsorption in Cystic Fibrosis: Comparison of Quantitative Fat Assay and a Novel Assay Using Fecal Lauric/Behenic Acid

“…The fat content of all food consumed was calculated to obtain total fat intake for each participant. At the end of the 72-hour collection, all of the stools were pooled and analysis performed using nuclear magnetic resonance (5,6) by Mayo Clinic Laboratories (Rochester, MN). All of the results were expressed as the CFA: CFA% ¼ dietary fat intake À fecal fat output dietary fat intake  100%…”

A Simple Colorimetric Method to Quantify Total Fecal Oil Using Oil-soluble Dyes in Laboratory Animals and Its Correlation with Liquid Chromatography-Mass Spectrometry Analysis

“…To measure the amount of the total fecal fats excreted by mice that consumed the dye/lard solution, gravimetric analysis was used. 2,8,11 The amount of lard in the excrement was weighed after the organic solvent in the supernatant of the excrement mixture was evaporated.…”

“…To measure fecal fat easily, quickly, and cost-effectively, several other methods have been developed. 2,8 These methods share a common approach in that lipid is directly quantified by various extraction methods. Since the results of lipid determination depend on the lipid extraction process, this extraction process assumes significance.…”