title: Systematic study of long-term stability of 3,4-dihydroxyphenylglycol in plasma for subsequent determination with liquid chromatography.
abstract: The effect of three storage temperature levels (i.e. +4, -20 and -80 degrees C) and time intervals from sampling (3, 6 and 9 months) on the degradation of 3,4-dihydroxyphenylglycol (DHPG) and norepinephrine (NE) was investigated in a systematic study. Extracted human plasma samples and acidified standard solutions were stored for long periods (up to 9 months) without the addition of any stabilizing agent. DHPG and NE values, determined using a ion-pair reversed-phase high-performance liquid chromatography method with electrochemical detection of coulometric type (IP-RP-HPLC-CD), remained constant over time in those plasma samples and standard solutions that had been stored at the lowest storing temperature (i.e. -80 degrees C). The expected degradation was observed at higher temperature levels. Plasma and standard DHPG degradation can, therefore, be prevented by storing samples at a lower temperature than previously suggested with no need to add any stabilizing agent.
authors.affiliation: Department of Medicine and Medical Specialties, University of Modena and Reggio Emilia, Modena, Italy. mgv28@libero.it
authors.forename: Maria Grazia
authors.initials: MG
authors.lastname: Venneri
authors.forename: Graziano
authors.initials: G
authors.lastname: Del Rio
mesh_terms: D002138:Calibration; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D004563:Electrochemistry; D006801:Humans; D008734:Methoxyhydroxyphenylglycol / Q000031:analogs & derivatives* / Q000097:blood*; D012015:Reference Standards; D012680:Sensitivity and Specificity
chemical_list: D008734:Methoxyhydroxyphenylglycol; C010117:3,4-dihydroxyphenylglycol