A new Fourier transform infrared method for the determination of moisture in edible oils

Ahmed Al-Alawi, Frederick R. Van De Voort, Jacqueline Sedman

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

A rapid, practical, and accurate Fourier transform infrared (FT-IR) method for the determination of moisture content in edible oils has been developed based on the extraction of water from oil samples into dry acetonitrile. A calibration curve covering a moisture content range of 0-2000 ppm was developed by recording the mid-infrared (MIR) spectra of moisture standards, prepared by gravimetric addition of water to acetonitrile that had been dried over molecular sieves, in a 500 μm ZnSe transmission flow cell and ratioing these spectra against that of the dry acetonitrile. Water was measured in the resulting differential spectra using either the OH stretching (3629 cm-1) or bending (1631 cm-1) bands to produce linear standard curves having standard deviations (SDs) of approximately ±20 ppm. For moisture analysis in oils, the oil sample was mixed with dry acetonitrile in a 1:1 w/v ratio, and after centrifugation to separate the phases, the spectrum of the upper acetonitrile layer was collected and ratioed against the spectrum of the dry acetonitrile used for extraction. The method was validated by standard addition experiments with samples of various oil types, as well as with oil samples deliberately contaminated with alcohols, hydroperoxides, and free fatty acids to investigate possible interferences from minor constituents that may be present in oils and are potentially extractable into acetonitrile. The results of these experiments confirmed that the moisture content of edible oils can be assessed with high accuracy (on the order of ±10 ppm) by this method, thus providing an alternative to the conventional, but problematic, Karl Fischer method and facilitating the routine analysis of edible oils for moisture content.

Original languageEnglish
Pages (from-to)1295-1299
Number of pages5
JournalApplied Spectroscopy
Volume59
Issue number10
DOIs
Publication statusPublished - Oct 2005

Fingerprint

Oils and fats
Acetonitrile
moisture
Fourier transforms
Moisture
oils
Oils
acetonitrile
Infrared radiation
moisture content
Water
Centrifugation
Molecular sieves
water
Fatty acids
Nonesterified Fatty Acids
Hydrogen Peroxide
Stretching
absorbents
curves

Keywords

  • Acetonitrile
  • Edible oils
  • Fourier transform infrared spectroscopy
  • FT-IR spectroscopy
  • Moisture content

ASJC Scopus subject areas

  • Spectroscopy
  • Instrumentation

Cite this

A new Fourier transform infrared method for the determination of moisture in edible oils. / Al-Alawi, Ahmed; Van De Voort, Frederick R.; Sedman, Jacqueline.

In: Applied Spectroscopy, Vol. 59, No. 10, 10.2005, p. 1295-1299.

Research output: Contribution to journalArticle

Al-Alawi, Ahmed ; Van De Voort, Frederick R. ; Sedman, Jacqueline. / A new Fourier transform infrared method for the determination of moisture in edible oils. In: Applied Spectroscopy. 2005 ; Vol. 59, No. 10. pp. 1295-1299.
@article{e30a02f3fa27486690615f53cfb9a973,
title = "A new Fourier transform infrared method for the determination of moisture in edible oils",
abstract = "A rapid, practical, and accurate Fourier transform infrared (FT-IR) method for the determination of moisture content in edible oils has been developed based on the extraction of water from oil samples into dry acetonitrile. A calibration curve covering a moisture content range of 0-2000 ppm was developed by recording the mid-infrared (MIR) spectra of moisture standards, prepared by gravimetric addition of water to acetonitrile that had been dried over molecular sieves, in a 500 μm ZnSe transmission flow cell and ratioing these spectra against that of the dry acetonitrile. Water was measured in the resulting differential spectra using either the OH stretching (3629 cm-1) or bending (1631 cm-1) bands to produce linear standard curves having standard deviations (SDs) of approximately ±20 ppm. For moisture analysis in oils, the oil sample was mixed with dry acetonitrile in a 1:1 w/v ratio, and after centrifugation to separate the phases, the spectrum of the upper acetonitrile layer was collected and ratioed against the spectrum of the dry acetonitrile used for extraction. The method was validated by standard addition experiments with samples of various oil types, as well as with oil samples deliberately contaminated with alcohols, hydroperoxides, and free fatty acids to investigate possible interferences from minor constituents that may be present in oils and are potentially extractable into acetonitrile. The results of these experiments confirmed that the moisture content of edible oils can be assessed with high accuracy (on the order of ±10 ppm) by this method, thus providing an alternative to the conventional, but problematic, Karl Fischer method and facilitating the routine analysis of edible oils for moisture content.",
keywords = "Acetonitrile, Edible oils, Fourier transform infrared spectroscopy, FT-IR spectroscopy, Moisture content",
author = "Ahmed Al-Alawi and {Van De Voort}, {Frederick R.} and Jacqueline Sedman",
year = "2005",
month = "10",
doi = "10.1366/000370205774430846",
language = "English",
volume = "59",
pages = "1295--1299",
journal = "Applied Spectroscopy",
issn = "0003-7028",
publisher = "Society for Applied Spectroscopy",
number = "10",

}

TY - JOUR

T1 - A new Fourier transform infrared method for the determination of moisture in edible oils

AU - Al-Alawi, Ahmed

AU - Van De Voort, Frederick R.

AU - Sedman, Jacqueline

PY - 2005/10

Y1 - 2005/10

N2 - A rapid, practical, and accurate Fourier transform infrared (FT-IR) method for the determination of moisture content in edible oils has been developed based on the extraction of water from oil samples into dry acetonitrile. A calibration curve covering a moisture content range of 0-2000 ppm was developed by recording the mid-infrared (MIR) spectra of moisture standards, prepared by gravimetric addition of water to acetonitrile that had been dried over molecular sieves, in a 500 μm ZnSe transmission flow cell and ratioing these spectra against that of the dry acetonitrile. Water was measured in the resulting differential spectra using either the OH stretching (3629 cm-1) or bending (1631 cm-1) bands to produce linear standard curves having standard deviations (SDs) of approximately ±20 ppm. For moisture analysis in oils, the oil sample was mixed with dry acetonitrile in a 1:1 w/v ratio, and after centrifugation to separate the phases, the spectrum of the upper acetonitrile layer was collected and ratioed against the spectrum of the dry acetonitrile used for extraction. The method was validated by standard addition experiments with samples of various oil types, as well as with oil samples deliberately contaminated with alcohols, hydroperoxides, and free fatty acids to investigate possible interferences from minor constituents that may be present in oils and are potentially extractable into acetonitrile. The results of these experiments confirmed that the moisture content of edible oils can be assessed with high accuracy (on the order of ±10 ppm) by this method, thus providing an alternative to the conventional, but problematic, Karl Fischer method and facilitating the routine analysis of edible oils for moisture content.

AB - A rapid, practical, and accurate Fourier transform infrared (FT-IR) method for the determination of moisture content in edible oils has been developed based on the extraction of water from oil samples into dry acetonitrile. A calibration curve covering a moisture content range of 0-2000 ppm was developed by recording the mid-infrared (MIR) spectra of moisture standards, prepared by gravimetric addition of water to acetonitrile that had been dried over molecular sieves, in a 500 μm ZnSe transmission flow cell and ratioing these spectra against that of the dry acetonitrile. Water was measured in the resulting differential spectra using either the OH stretching (3629 cm-1) or bending (1631 cm-1) bands to produce linear standard curves having standard deviations (SDs) of approximately ±20 ppm. For moisture analysis in oils, the oil sample was mixed with dry acetonitrile in a 1:1 w/v ratio, and after centrifugation to separate the phases, the spectrum of the upper acetonitrile layer was collected and ratioed against the spectrum of the dry acetonitrile used for extraction. The method was validated by standard addition experiments with samples of various oil types, as well as with oil samples deliberately contaminated with alcohols, hydroperoxides, and free fatty acids to investigate possible interferences from minor constituents that may be present in oils and are potentially extractable into acetonitrile. The results of these experiments confirmed that the moisture content of edible oils can be assessed with high accuracy (on the order of ±10 ppm) by this method, thus providing an alternative to the conventional, but problematic, Karl Fischer method and facilitating the routine analysis of edible oils for moisture content.

KW - Acetonitrile

KW - Edible oils

KW - Fourier transform infrared spectroscopy

KW - FT-IR spectroscopy

KW - Moisture content

UR - http://www.scopus.com/inward/record.url?scp=27644531841&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=27644531841&partnerID=8YFLogxK

U2 - 10.1366/000370205774430846

DO - 10.1366/000370205774430846

M3 - Article

VL - 59

SP - 1295

EP - 1299

JO - Applied Spectroscopy

JF - Applied Spectroscopy

SN - 0003-7028

IS - 10

ER -