The QuadJet™ SD from Leco for FID GCxGC

The QuadJet™ SD from LECO is the perfect solution for specimens that arrive in laboratories. It combines the sensitivity of flame ionization detection (FID) with the increased chromatographic resolution of in-depth 2D gas chromatography (GCxGC) to provide an improved measurement of real components of users’ samples when compared to a straight GC analysis.

No other commercially available system can deliver the same reduction in error and noise as the QuadJet SD.


  • User-friendly ChromaTOF®-based software offers acquisition processing and reporting functionality within a solo package
  • Improved separating power for analyzing complex samples
  • Available cryogen-free modulator prevents the requirement for LN2 dewars
  • Classification software feature eases the identification of components

Theory of Operation

When conducting GC-FID analysis, a majority of laboratories measure compounds using the area of the FID signal. But real-world samples are seldom simple and clean. For instance, a diesel sample can have an unlimited number of various compounds in just one injection.

If there are more compounds in a sample, the chance of coelution will be higher. This coelution will boost the FID signal, thereby leading to a high bias error in the measurement. With GCxGC conducting two individual chromatographic separations in a single experiment, the precision of the FID measurement is sustained.

The orthogonal nature of the separation mechanism in GCxGC makes it easy to pull apart coeluting compounds in just one run. By integrating a modulation device, the LECO QuadJet SD and other true GCxGC instruments improve upon by just running the same specimen via two different columns.

Peaks that elute from the primary column are quantitatively separated into smaller sections before they are released onto the second column. This segmentation, together with the cryo-focusing of the modulator, can provide peak widths as narrow as 50 ms to the second column.

Thermal Modulation

Thermal modulation is the ideal performing modulator for GCxGC than thermal modulation because other thermal modulators cannot match up to the performance, reliability, and robustness of LECO’s GCxGC modulator. With the QuadJet SD from LECO, modulation is achieved through a dual-stage, quad-jet thermal modulator placed between the pair of columns.

The thermal modulator from LECO enables on-column cryo-focusing inside the GCxGC system, offering increased peak detectability and increased isolation of coeluting compounds with an order-of-magnitude increase in signal-to-noise.

The Consumable-Free Modulator (which does not use liquid nitrogen) from LECO is an available option, which saves cost and time without affecting the performance when modulating moderately volatile compounds.

The QuadJet SD from LECO has been developed to offer users the upper hand in laboratory productivity. The user-friendly feature of the QuadJet SD combined with the industry’s best secondary oven for the secondary column enables enhanced analytical results.

When users take the step to the next dimension in gas chromatography, they should make sure that they are taking the step that will allow them to see what they have been missing.

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