Related Experiment Video
Updated: May 5, 2026
14:22
Free Radicals in Chemical Biology: from Chemical Behavior to Biomarker Development
Published on: April 15, 2013
20.7K
Pigment versus cholesterol cholelithiasis: identification and quantification by infrared spectroscopy
Gastroenterology
|March 1, 1977
Summary
Gallstone analysis reveals two distinct types of pigment stones using infrared spectroscopy. This advanced technique improves the characterization of gallstone composition, differentiating them from cholesterol stones.
Area of Science:
- Biochemistry
- Spectroscopy
- Gastroenterology
Background:
- Previous studies indicated pigment stones constitute 27% of gallstones after cholecystectomy.
- Standard biochemical methods limited pigment stone quantitation due to insolubility (66% of weight).
- Cholesterol stones are primarily composed of cholesterol (77% dry weight), while pigment stones contain minimal unconjugated bilirubin (7%).
Purpose of the Study:
- To further characterize pigment and cholesterol gallstone composition.
- To quantitate pigment, carbonate, and cholesterol in gallstones using infrared spectroscopy.
- To differentiate gallstone types based on their chemical makeup.
Main Methods:
- Infrared spectroscopy was employed to quantitate components without requiring crystallinity or solubilization.
- Standard biochemical assays were used for measuring other organic and inorganic components.
- Gallstones were analyzed for pigment, carbonate, and cholesterol content.
Main Results:
- Infrared spectroscopy identified two types of pigment stones: carbonate-containing and noncarbonate.
- Carbonate pigment stones showed higher levels of calcium, carbonate, and phosphate, but less pigment compared to noncarbonate stones.
- The total measured components in pigment stones increased significantly (6-fold) from 10% to 63% compared to initial reports.
- Cholesterol was confirmed as the major component in cholesterol stones by both chemical assay and infrared spectroscopy.
- 80% of the insoluble residue in limited solubility cholesterol stones was identified as cholesterol.
Conclusions:
- Quantitative infrared spectroscopy, combined with biochemical methods, enhances the understanding of gallstone composition.
- The study confirms distinct compositional differences between pigment and cholesterol gallstones.
- Two subtypes of pigment gallstones (carbonate-containing and noncarbonate) were identified, differing in mineral content.
More Related Videos
Related Concept Videos
01:16Spectrophotometry: Introduction
8.4K
Spectrophotometry is the quantitative measurement of the absorption, reflection, diffraction, or transmission of electromagnetic radiation through a material as a function of the intensity and wavelength of the radiation. A spectrophotometer is a device used to measure the change in the radiation intensity caused by its interaction with the material.
The essential components of a spectrophotometer include a source of electromagnetic radiation, a slot for placing a material to be analyzed, and a...
The essential components of a spectrophotometer include a source of electromagnetic radiation, a slot for placing a material to be analyzed, and a...
8.4K
01:09Infrared (IR) Spectroscopy: Overview
6.8K
When electromagnetic radiation passes through a material, atoms or molecules transition from a lower to a higher energy state by absorbing radiation corresponding to the energy difference between the two states. The absorption of infrared (IR) radiation causes transitions between vibrational energy levels in a molecule. Therefore, IR spectroscopy is a useful analytical tool for determining the molecular structure of molecules.
Different compounds display unique properties due to their...
Different compounds display unique properties due to their...
6.8K
01:29IR and UV–Vis Spectroscopy of Aldehydes and Ketones
5.1K
Infrared spectroscopy, also known as vibrational spectroscopy, is mainly used to determine the types of bonds and functional groups in molecules. In aldehydes and ketones, the carbonyl (C=O) bond shows an absorption around 1710 cm-1. The C=O bond vibration of an aldehyde occurs at lower frequencies than that of a ketone. In addition to the C=O absorption in an aldehyde, the aldehydic C–H bond also gives two peaks in the 2700–2800 cm-1 range. This absorption, coupled with the...
5.1K
01:28IR and UV–Vis Spectroscopy of Carboxylic Acids
4.6K
In IR spectroscopy of carboxylic acids, the C=O bond shows a characteristic band between 1710 and 1760 cm⁻¹, and the O–H bond exhibits a broad band between 2500 and 3300 cm⁻¹.
However, the stretching absorptions for the C=O bond vary depending on the structure of carboxylic acids. The C=O bond of the free carboxylic acids shows a higher stretching frequency, 1760 cm−1, while H-bonded carboxylic acids (dimers) exhibit stretching absorptions at a lower frequency,...
However, the stretching absorptions for the C=O bond vary depending on the structure of carboxylic acids. The C=O bond of the free carboxylic acids shows a higher stretching frequency, 1760 cm−1, while H-bonded carboxylic acids (dimers) exhibit stretching absorptions at a lower frequency,...
4.6K
01:29UV–Vis Spectroscopy: Woodward–Fieser Rules
30.7K
UV–Visible absorption spectra of conjugated dienes arise from the lowest energy π → π* transitions. The light-absorbing part of the molecule is called the chromophore, and the substituents directly attached to the chromophore are called auxochromes. A strong correlation exists between the absorption maxima, λmax, and the structure of a conjugated π system. The Woodward–Fieser rules predict the value of λmax for a...
30.7K
01:25IR Spectrometers
3.1K
There are two main infrared (IR) spectrophotometers: dispersive IR spectrometers and Fourier transform infrared (FTIR) spectrometers. In a dispersive IR spectrometer, a beam of infrared radiation produced by a hot wire is divided into two parallel equal-intensity beams using mirrors. One beam passes through the sample, while another is a reference beam. The beams then move through the monochromator, which separates the radiations into a continuous spectrum of different frequencies. The...
3.1K