derivatizations for improved detection of alcohols by gas chromatography and photo ionization...
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Derivatizations for Improved Detection of
Alcohols by Gas Chromatography and
Photoionization Detection (GC-PID)Authors: I. S. Kruil
a; M. Swartz
a; J. N. Driscoll
b
Affiliations:a
The Barnett Institute and Department of Chemistry, Northeastern University,Boston, Massachusetts, USAb
HNU Systems, Inc., Highlands, Massachusetts, USADOI: 10.1080/00032718408059851
Publication Frequency: 18 issues per year
Published in: Analytical Letters, Volume 17, Issue 20 1984 , pages 2369 - 2384
Subjects: Analytical Chemistry; Chemical Spectroscopy; Forensic Chemistry; Formats available: PDF (English)
Abstract
Pentafluorophenyldimethylsilyl chloride (flophemesyl chloride, F1) is a well knownderivatization reagent for improved electron capture detection (ECD) in gas chromatography
(GC)(GC-ECD), but it has never been utilized for improved detectability and sensitivity in GC-photoionization detection (GC-PID). We have now utilized a wide variety of flophemesyl
alcohol derivatives in order to show a new approach for realizing greatly reduced minimumdetection limits (MDL) of virtually all alcohol derivatives in GC-PID analysis. This particular
derivatization approach is inexpensive and easy to apply, leading to quantitative or near 100%
conversion of the starting alcohols to the expected flophemesyl ethers (silyl ethers). Detectionlimits can be lowered by 2-3 orders of magnitude for such derivatives when compared with thestarting alcohols, along with calibration plots that are linear over 5-7 orders of magnitude.
Specific GC conditions have been developed for many flophemesyl derivatives, in all cases usingpacked columns. Both ECD and PID relative response factors (RRFs) and normalized RRFs have
been determined, and such ratios can now be used for improved analyte identification fromcomplex sample matrices, where appropriate.
We have attempted to describe in this preliminary report some interesting results and approaches
for improved GC-PID detection of a large number of alcohols and alcohol analogs. The methodof derivatization is extremely simple to perform, and appears to lead to a single, well-defined
product of known structure in 100% yield or thereabouts. Chromatography for typicalflophemesylalcohol analytes can be excellent, as in Figure 1, with symmetrical peak shape, little
or no tailing, and overall excellent MDLs. With GC-detector-computer interfacing, we are ableto obtain both chromatograms and preliminary as well as calculated data within a single 5-10
minute time span27
The total amount of time per analysis will obviously depend on the particularanalyte derivative and the chromatography obtained. RRFs and normalized RRFs are quite easyto determine, they are fully reproducible, and can serve as good markers for a particular alcohol
and its flophemesyl derivative. In view of the calibration plots possible and MDLs, these overall
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First HNU PI 51 Replacement PID PI52-C
1975 2008
Max. T (o
C) 225 275
Ion chamb.
Material
Teflon Ceramic & gold
Dead Volume (uL) 350 50
Det. Limit ppb 20.0 0.5
Lamp lifetime
(hrs.)
5,000 5,000
The early work (1976-78) was done with an HNU PI51 shown above. The replacement instrument (with
improved specs) is a P I52-01C manufactured by:
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PID Analyers, LLC, 2 Washington Circle, Sandwich, MA 02563 T 1 774 479 5281
Email: [email protected]
URL: http:/ / www.hnu.com
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