Operating Principle:When each component dissolved in mobile phase gets through stationary phase, the intension and extend of reaction (i.e., adsorption, distribution, ionic attraction, exclusion and affinity) are varied. This results in different outflowrate and retention time to detector.

Component to be analyzed:Liquid chromatography is suitable to be used in separation of low-volatile or non-volatile compounds, which may have poor thermal stability. Currently, the uses of LC DAD system include measurement of atmospheric carbonyl compounds in gas and particle phases and determination of amount of hydroxyl (∙OH) induced from particulate matters in filter samples.

Pretreatment Steps:Environmental samples are extracted with appropriate organic reagents before injection into the LC system. Filtration is always required to avoid potential block of mobile phase flow from debris or impurities.

Test Parameters:The system is used for trace organic analysis.Under the optimum conditions, the detection limits ranged fromsub-pptv to ppbv level.