Gas Chromatography Systems

What is Gas Chromatography? 

Chromatography is the science of separating a mix of compounds into homogeneous groups; Gas Chromatography is the separation of a mix of compounds in the gas phase.

How Are Compounds Separated? 

Compounds can be separated in a variety of ways. In Gas Chromatography analysis, a GC system consists of an inlet, a capillary tube, and a detection device all mounted to an oven.

When a sample is injected into the inlet, it is picked up by a gas flow and passed into the capillary column. The column is then heated by the oven and the compounds separate by boiling point. Generally speaking, lighter and smaller compounds have a lower boiling point and migrate through the column faster than heavier or larger compounds. At the exit of the column, you find the detector that works to identify the compounds as they exit the column.

What Does a GC Detector Do?

GC detectors work in various different ways. Most of the time detectors will destroy the compounds as they pass through and a particular reaction will give a response, or peak in the detector. The GC operator can have a better understanding of the compound's identity based on the time it takes for the migration, and the detector's response. 

GC Detectors are designed with varying levels of sensitivity and detection, and the method of which they destroy the sample to produce a response.


The PFPD is a pulsed flame photometric detector. This means a flame is ignited as the sample and carrier gas exits the column. The photometric detector analyzes the light produced from the combustion and determines the constituents of the compounds. The PFPD is great for sulfur.


The ELCD, or electrolytic conductivity detector, uses a recycling stream of solvent to pick up a carrier gas and sample that has passed through a heated (900-1000*C) reactor. The resulting gas/solvent mixture is passed through a conductivity cell that produces a change in electric potential (peak).


The XSD is similar to the ELCD but uses no solvent stream, but rather uses a probe inserted at the end of the catalytic reaction tube. As the compounds hit the probe there is a thermos ionic response detected to generate the peak.


The PID is a non-destructive detector that uses a UV lamp to excite photo-active compounds to a higher electric state. These compounds are then detected by a sensor within the PID body where the peak is generated. Since the PID is non-destructive it can be used in tandem with the above detectors (with the exception of PFPD) where the compounds can be passed through the detector and then into a destructive detector.

The Impact of GC Systems & Detectors 

GC systems are utilized for many types of analysis where organic compounds are largely the focus. Laboratories trying to determine the amount of organic compounds in a given sample or what specific organic compounds a given sample contains.

GC Systems and detectors are great for laboratories that need to analyze organic compounds when other analytical chemistry methods are not feasible or appropriate, such as wet chemistry. Enviornmental and Food & Beverage labs, as well as oil & gas or petrochemical laboratories, are always searching for the lowest detection level. 

Gas Chromatography Equipment at OI Analytical

Xylem Lab Solutions unifies a variety of instruments to serve a single purpose: provide technical solutions for laboratories across the globe. Our Gas Chromatography (GC) portfolio is designed to improve the way resources are used and conserved in the lab, regardless of application. Our detectors are great for specific applications where target compounds are mostly known to be absent and the analysis is a confirmation of that. 

Our innovative product portfolios provide sustainable solutions for our customers and our communities.

Selective GC Detectors

Our selective GC detectors provide solutions to challenging analytical applications. Detecting sulfur and halogenated species in petrochemicals, trace levels of organochlorine and organophosphorus pesticides in food or environmental samples, and 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, Shimadzu, Thermo, and PerkinElmer.

gc detector pid fid

Photoionization Detector/Electrolytic Conductivity Detector (PID/ELCD)
halogen selective detector
electrolytic conductivity detector elcd

Gas Chromatography Systems

Our high-performance, fully integrated GC systems are optimal for analyzing several compound classes in a variety of matrices with excellent selectivity and sensitivity. For example, our BTEX system with Purge and Trap (P&T) extracts compounds from a representative sample, chromatographically separates, and selectively detects target compounds following specific regulatory methods to measure aromatic, aliphatic, and halogenated hydrocarbons in environmental samples. Our pesticide system may utilize either the ELCD or XSD for selective analysis of pesticides and PCBs. The SPRO system is designed for the analysis of sulfur compounds in gas phase samples. The fluorinated by-product system (FBA) uses the ELCD to measure total fluorinated contaminants in petrochemical streams.

voc analysis system
btex gro analysis system

gc system sulfur analysis
fluorinated by products analyzer

Sample Processors & Sample Introduction

Maximize your laboratory’s efficiency and investment with our state of the art P&T concentrators and autosamplers. Chemists around the world rely on our equipment for accurate and dependable results. Our slim-line, open architecture P&T design saves benchtop space, simplifies troubleshooting, and minimizes downtime. With proven technology, intuitive software, and trusted engineering our sample introduction systems contribute to laboratory efficiency and productivity.

purge and trap sample concentrator
water soil sample processor

purge and trap water autosampler
standards addition module