title: Determination of furfurals in Manuka honey using piston-cylinder liquid-liquid extraction and gas chromatography.
abstract: A rapid analytical approach for the direct measurement of furfurals such as 2-furfural and 5-methyl-2-furfural at parts-per-billion level in Manuka honey is described. The approach employs a piston-cylinder based liquid-liquid extraction device using chloroform extraction solvent. This device substantially reduces extraction time by a factor of 120 times compared to solid phase micro-extraction and reduces solvent consumption by a factor of 25 times compared to liquid-liquid extraction with mechanical agitation. A recently commercialised capillary column offering a high degree of inertness permits separation and detection of the analytes at ultra-trace level without derivatisation. A three-port planar microfluidic device with a mid-point pressure is also incorporated to back-flush heavier compounds in the matrix to improve column longevity and overall system cleanliness. With this approach, analysis is conducted in less than 7min. Repeatability of retention times for all compounds is less than 0.1% (n=20). The compounds cited can be analysed over a range from 1ng/g to 10μg/g in honey with a 5ng/g limit of quantification (LOQ) and correlation coefficients of at least 0.999. Relative precision is less than 2.8% RSD (n=20) at 50ng/g level with analyte extraction efficiency of greater than 99% (n=3) over a range from 5ng/g to 10μg/g in the matrix described. The analytical system requires only minimal maintenance and is suitable for remote site deployment. Under the analytical conditions established and with a practical LOQ of 5ng/g, 100 samples can be analysed before septum/liner/o-ring replacements are needed. As a preventive measure, the pre-column can be replaced once every six months to maintain chromatographic fidelity.
authors.affiliation: University of Alberta, 116 Street and 85 Avenue, Edmonton, Alberta T6G 2R3, Canada.
authors.forename: K
authors.initials: K
authors.lastname: Gras
authors.affiliation: Australian Centre for Research on Separation Science (ACROSS), University of Tasmania, Private Bag 75, Hobart, Tasmania 7001, Australia; Dow Chemical Canada ULC, Highway 15, Fort Saskatchewan, Alberta T8L 2P4, Canada.
authors.forename: J
authors.initials: J
authors.lastname: Luong
authors.affiliation: Dow Chemical Canada ULC, Highway 15, Fort Saskatchewan, Alberta T8L 2P4, Canada.
authors.forename: R
authors.initials: R
authors.lastname: Gras
authors.affiliation: Australian Centre for Research on Separation Science (ACROSS), University of Tasmania, Private Bag 75, Hobart, Tasmania 7001, Australia; HJ Cortes Consulting LLC, Midland, MI 48642, USA.
authors.forename: H J
authors.initials: HJ
authors.lastname: Cortes
authors.affiliation: Australian Centre for Research on Separation Science (ACROSS), University of Tasmania, Private Bag 75, Hobart, Tasmania 7001, Australia. Electronic address: robert.shellie@utas.edu.au.
authors.forename: R A
authors.initials: RA
authors.lastname: Shellie
mesh_terms: D002849:Chromatography, Gas / Q000379:methods*; D005662:Furaldehyde / Q000031:analogs & derivatives* / Q000032:analysis; D006722:Honey / Q000032:analysis*; D059625:Liquid-Liquid Extraction / Q000379:methods*; D012997:Solvents / Q000737:chemistry
chemical_list: D012997:Solvents; C048065:5-methyl-2-furfural; D005662:Furaldehyde
keywords: 2-Furfural; 5-Methyl-2-furfural; DB-624UI; Manuka honey; Mixxor; Piston-cylinder extraction