Selective Detectors forGas Chromatography

While gas chromatography coupled with mass spectrometry (GC-MS) is a powerful analytical technique, there are significant advantages to using selective GC detectors alone or in tandem with a MS detector for many applications.

A mass spectrometer is a universal, nonselective detector that yields total ion chromatograms containing a large number of compounds. Post-run mass spectra library searching is required to identify target compounds.

Selective GC detectors enhance chromatographic performance by measuring trace levels of target compounds in the presence of higher concentration compounds, or matrix interferences.

Selective GC detectors provide precise retention time marking for improved MS library matching and peak identification.

Co-elution of interferences in essential oils can make locating compounds responsible for characteristic aromas in a MS chromatogram quite difficult. The accompanying GC-MS total ion chromatogram of galbanum oil contains a large number of co-eluted compounds. A simultaneous sulfur mode PFPD chromatogram helps pinpoint sulfur compounds contributing to the fragrance profile of the oil.

Enhancing Chromatographic Performance

Simultaneous sulfur mode PFPD chromatogram of galbanum oil.

FID chromatogram of galbanum oilGC-MS total ion chromatogram of galbanum oil.

Abundance

5e+07

4.5e+07

4e+07

3.5e+07

3e+07

2.5e+07

2e+07

1.5e+07

1e+07

5000000

Time 20.00 40.00 60.00

20.00 40.00 60.00

Abundance2.2e+07

2e+07

1.8e+07

1.6e+07

1.4e+07

1.2e+07

1e+07

8000000

6000000

4000000

2000000

Time 20.00 40.00 60.00

Abundance 1600000

1500000

1300000

1200000

1100000

1000000

900000

800000

700000

600000

500000

400000Time 34.00 35.00 36.00 37.00 38.00 39.00 40.00

Abundance1e+07

9000000

8000000

7000000

6000000

5000000

4000000

3000000

2000000

1000000

Time

ELCD

PFPD

XSD

PID

PID/FID

PID/ELCD

PID/XSD

Enhancing Chromatographic Performance

Selective GC Detectors for Challenging Analytical Applications

OI Analytical’s selective GC detectors provide solutions to challenging analytical applications. Detecting sulfur species in petrochemicals, trace levels of organochlorine and organophosphorus pesticides in food samples, or sulfur and aromatic compounds in flavor and fragrance extracts are prime examples of applications that benefit from the use of selective GC detectors.

Compatible detectors are available for current models of GC instruments manufactured by Agilent, Bruker, Shimadzu, Thermo, and PerkinElmer.

Aromatics

Alkenes

Arsenic/Tin

BTEX

Chemical Weapon Agents (CWA)

Chlorinated Pesticides

Chlorinated VOC’s

Herbicides

Olefins

Organofluoride Compounds

PCBs

Phosphorus Compounds

S/P Pesticides

Sulfur Compounds

Trihalomethanes (THM)

VOCs

Selective GC Detectors

151 Graham RoadPO Box 9010College Station, Texas 77842-9010

(979) 690-1711(800) 653-1711 USA/CanadaFAX (979) 690-0440

www.oico.comE-mail: oi-mail@xyleminc.com

Publication 31670416

PFPD – Pulsed Flame Photometric DetectorThe PFPD excels at selective detection of sulfur and phosphorus compounds, and can be configured to detect 26 other elements.

XSDTM – Halogen Specific DetectorThe XSD halogen specific detector is designed for selective detection of halogenated compounds such as pesticides, THMs, and PCBs.

Tandem GC DetectorsOI Analytical’s patented* tandem GC detectors combine a photoionization detector (PID) with an FID or second selective detector providing two simultaneous chromatograms from a single run. The PID selectively responds to aromatic and unsaturated hydrocarbons in the presence of alkanes and saturated hydrocarbons. The second detector is used to further differentiate and identify compounds with specific heteroatoms.

ELCD-Electrolytic Conductivity DetectorThe ELCD is designed for high sensitivity measurement of halogenated compounds. Interfacing an ELCD with a PID as tandem detectors is prescribed in USEPA methods 502.2 and 8021 for measurement of chlorinated and aromatic volatile organic compounds (VOCs) in drinking water and wastewater samples.

* U.S. Patents 4,804,846 and 5,578,271