When performing GC-FID analysis, most laboratories quantify compounds using the area of the FID signal. Real world samples are rarely clean and straightforward. For example, a diesel sample can have thousands of different compounds in a single injection. The more compounds in a sample, the higher the chance of coelution; this coelution will increase the FID signal, thus creating a high bias error in the measurement. With GC×GC performing two separate chromatographic separations in one experiment, the accuracy of the FID measurement is maintained.
Due to the orthogonal nature of the separation mechanism in GCxGC, coeluting compounds are easily pulled apart in a single run. True GC×GC instruments, such as the LECO QuadJet SD, improve upon simply running the same sample through two different columns by incorporating a modulation device. Peaks eluting from the primary column are quantitatively segmented into smaller sections prior to release onto the second column. This segmenting, along with the cryo-focusing of the modulator, can deliver peak widths as narrow as 50 ms to the second column.
There is no better-performing modulator for GC×GC than thermal modulation, and not even other thermal modulators can match up to the ruggedness, reliability, and performance of LECO’s GC×GC modulator. With LECO’s QuadJet SD, modulation is accomplished via a dual-stage, quad-jet thermal modulator positioned between the two columns. LECO’s thermal modulator allows for on-column cryo-focusing within the GC×GC system, providing increased peak detectability and increased separation of coeluting compounds for an order-of-magnitude increase in signal-to-noise.
LECO’s Consumable-Free Modulator (which does not utilize Liquid Nitrogen) is an available option, saving time and money without sacrificing performance when modulating moderately volatile compounds.
LECO’s QuadJet SD is designed to give you the upper hand in laboratory productivity. Its ease-of-use and industry’s best secondary oven for the secondary column allows for improved analytical results. When you take the step to the next dimension in gas chromatography, make sure you’re taking the step that will let you see what you’ve been missing.