title: Analysis of tear glucose concentration with electrospray ionization mass spectrometry.
abstract: We have developed a mass spectrometry-based method that allows one to accurately determine the glucose concentration of tear fluid. We used a 1 microL micro-capillary to collect tear fluid from the tear meniscus with minimal irritation of the eye. We analyzed the 1 muL volume of collected tear fluid with liquid-chromatography electrospray ionization mass spectrometry with the use of D-glucose-6,6-d2 as an internal standard. Repeated measurements and a recovery experiment on pooled, onion-induced tears showed that the analysis of the glucose in tears was precise (4% relative standard deviation) and provided 100% recovery. We found the tear glucose concentration of one fasting nondiabetic subject to be 13 to 51 microM while the onion-induced tear glucose concentration of a different nondiabetic subject to be 211 to 256 microM.
authors.affiliation: Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA.
authors.forename: Christopher R
authors.initials: CR
authors.lastname: Taormina
authors.forename: Justin T
authors.initials: JT
authors.lastname: Baca
authors.forename: Sanford A
authors.initials: SA
authors.lastname: Asher
authors.forename: Joseph J
authors.initials: JJ
authors.lastname: Grabowski
authors.forename: David N
authors.initials: DN
authors.lastname: Finegold
mesh_terms: D002851:Chromatography, High Pressure Liquid; D005947:Glucose / Q000032:analysis* / Q000378:metabolism; D006801:Humans; D012016:Reference Values; D021241:Spectrometry, Mass, Electrospray Ionization; D013666:Tears / Q000737:chemistry* / Q000378:metabolism
chemical_list: D005947:Glucose