title: Increasing the sensitivity of headspace analysis of low volatility solutes through water removal by hydrate formation.
abstract: This paper reports on the development of a new headspace analytical technique that is based on water removal by hydrate formation (WRHF). By adding anhydrous salt, the liquid water in an aqueous sample will be removed leaving behind volatile analytes that are fully vaporized at temperatures well below their boiling points. With WRHF, the amount of sample in the headspace can be significantly increased, thereby dramatically improving the detection sensitivity. The technique reduces the risk of possible column damage in gas chromatography (GC) systems. The technique was applied to the determination of phenol at different stages of a coking wastewater treatment plant. The results showed that up to mL-levels of sample solution can be used in WRHF HS-GC analysis when 5g of CaCl2 were used as the anhydrous salt. The detection sensitivity for phenol content was 500 times greater than that in earlier HS-GC work that did not incorporate hydrate formation. The proposed WRHF headspace analysis technique is simple and practical, making it a useful tool for quantifying low concentrations of volatile analytes in aqueous samples.
authors.affiliation: State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou, China.
authors.forename: Hui-Chao
authors.initials: HC
authors.lastname: Hu
authors.affiliation: State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou, China. Electronic address: xschai@gmail.com.
authors.forename: Xin-Sheng
authors.initials: XS
authors.lastname: Chai
authors.affiliation: School of Environment and Energy, South China University of Technology, Guangzhou, China.
authors.forename: Chao-Hai
authors.initials: CH
authors.lastname: Wei
authors.affiliation: School of Environment and Energy, South China University of Technology, Guangzhou, China.
authors.forename: Donald
authors.initials: D
authors.lastname: Barnes
mesh_terms: D002849:Chromatography, Gas / Q000379:methods*; D010636:Phenols / Q000032:analysis; D012996:Solutions; D013696:Temperature; D014835:Volatilization; D014867:Water / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000302:isolation & purification; D018508:Water Purification
chemical_list: D010636:Phenols; D012996:Solutions; D014874:Water Pollutants, Chemical; D014867:Water
keywords: Coking wastewater; Full evaporation; Gas chromatography; Headspace analysis; Phenol; Water removal by hydrate formation