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Analysis of PAHs in the Environment by Gas Chromatography (GC) (CAT#: STEM-CT-2511-CJ)

Introduction

PAHs represent an important class of hazardous organic chemicals that are ubiquitous in the environment and are released from natural or anthropogenic sources. PAHs form, for example, as a result of incomplete combustion of fossil fuels and during the disposal of coal tar and chemical wastes. On the basis of their frequency of occurrence in the environment and their proved mutagenicity and carcinogenicity, 16 PAHs have been selected by the US EPA as priority pollutants. But PAHs with more than 24 carbon atoms cannot be analysed by GC because of their lack of volatility.




Principle

Chromatography is a technique that separates components in a mixture by the difference in partitioning behavior between mobile and stationary phases. Gas chromatography (GC) is one of the popular chromatography techniques to separate volatile compounds or substances. Components in the mixture are distributed between two phases, one of which is a stationary phase, and the other is a mobile phase gas, or carrier gas, that carries the mixture through the stationary phase. Compounds in the mobile phase interact with the stationary phase as they pass through. Due to the differences in properties and structures of each component, the size and affinity of each interaction with the stationary phase are different. Therefore, under the same driving force, the retention time of different components differs in the column, thus moving out of the column in different orders.

Applications

Environmental science; Chemical; Biochemistry

Procedure

1. The sample is introduced into a stream of inert gas, or a carrier, which is usually helium or argon. For a liquid sample, it needs to be evaporated before being injected into the carrier.
2. Sample components move through the packed column at a rate affected by the degree of interaction of each component with the stationary non-volatile phase. Substances that interact more with the stationary phase are delayed and thus separated from substances that interact less.
3. The components are eluted from the column.
4. Quantified and/or collected through the detector for further analysis.

Materials

• Sample: Environmental pollutants; Industrial by-products; Drugs; Food contaminants; Bodily fluids; Blood; Saliva; Serum; Plasma; Other secretions containing large amounts of organic volatiles; Pesticide; Metabolites of illicit and synthetic drugs; Liquid; Soil; Air; Fragrance; Plastic & More
• Equipment: Gas Chromatography (GC) Instruments
• (Optional): Gas Chromatography (GC) Detectors (Extensive Line of Gas Chromatography Detectors Including FID, ECD, NPD, PDD, TCD & FPD); Gas Chromatography (GC) Injectors; Gas Chromatography (GC) Autosamplers; Gas Chromatography (GC) Columns

Notes

1. Gas chromatography has good selectivity and can be used to analyze azeotropic mixtures and samples with close boiling points. For example, some isotopes, cis-trans isomers, adjacent or intertrans isomers, optical isomers, etc.
2. High separation efficiency and analysis speed.
3. Small sample consumption and high detection sensitivity.
4. Wide range of applications, although mainly used to analyze gases and volatile organic substances;under certain conditions, it can also be used to analyze high boiling point substances and solid samples.
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