On-line GC injector for liquid matrix
The injection system OLIS (On-line Liquid Injection System) is specially designed for the injection, in gas chromatography, of liquid matrixes up to a pressure of 60 bar. The advantage of this injector is its ability to work on-line, under pressure and without discrimination, unlike conventional injection systems.
Based on a simple operating principle: an actuator or stem is driven by a micro-electric motor from its upper position (filling stage) to its lower position (injection stage). This stem has a constant sampling volume of several hundred nanoliters and the liquid it contains is instantly vaporized by flash heating during injection. The OLIS valve is particularly suited for the analysis of liquid samples with a wide range of boiling points, viscous or with high polarity.
Advantages :
- Stand-alone and easy to use system
- Analysis of unstable liquid samples to be characterized
- Very little discrimination between compounds
- Adaptable to a new GC or an existing one
- Maintenance: low maintenance and easy to carry out by the user
- Better reproducibility than automatic injection with a syringe
Characteristics :
- Stem with a machined end to allow sample circulation
- Continuous or syringe-pushed sample circulation
- Instantaneous vaporization by flash heating of the liquid fraction contained in the calibrated volume
- Electronic interface with on-board intelligence integrating numerous control points (stem temperature, stem position at injection, etc…)
Application fields :
- LPG, LNG, naphtha, condensate
- ASTM D-2887
- Alcohols in hydrocarbons
- BTEX
- CO2 dissolved
- Impurities in amino matrix
Example of STEM heating during injection
