title: Applications of Tandem Mass Spectrometry (LC-MSMS) in estimating the post-mortem interval using the biochemistry of the vitreous humour.
abstract: It is widely accepted that the quantification of potassium concentrations ([K+]) and hypoxanthine ([Hx]) in the vitreous humour is useful in estimating the time of death within a recent time interval. Despite all the advances made in this area, it is well recognized that difficulties in calibration, validation and the use of different methodologies and instrumentation from different laboratories may lead to obtaining different concentrations from the same sample. The extraction of the vitreous humour itself should also be carried out with a precise technique, taking care during the procedure to avoid causing any vascular injury that might lead to haematic contamination. Any fluid that is not clear could lead to erroneous results and should be discarded. We present a new LC-MSMS method developed for quantitative and qualitative analysis of [Hx] (valid also for guanine and xanthine), and qualitative determination of uric acid in vitreous humour. We also introduce a methodology to assess haematic contamination in order to improve the estimation of time since death. The method was fully validated in terms of linearity, sensitivity, imprecision, analytical recovery, extraction and process efficiency and matrix effect.
authors.affiliation: Institute of Forensic Science, University of Santiago de Compostela, Spain.
authors.forename: Elena
authors.initials: E
authors.lastname: Lendoiro
authors.forename: Cristina
authors.initials: C
authors.lastname: Cordeiro
authors.forename: María S
authors.initials: MS
authors.lastname: Rodríguez-Calvo
authors.forename: Duarte N
authors.initials: DN
authors.lastname: Vieira
authors.forename: José M
authors.initials: JM
authors.lastname: Suárez-Peñaranda
authors.forename: Manuel
authors.initials: M
authors.lastname: López-Rivadulla
authors.forename: José I
authors.initials: JI
authors.lastname: Muñoz-Barús
mesh_terms: D002853:Chromatography, Liquid; D049429:Forensic Pathology; D006147:Guanine / Q000032:analysis; D006801:Humans; D019271:Hypoxanthine / Q000032:analysis; D057230:Limit of Detection; D011180:Postmortem Changes; D053719:Tandem Mass Spectrometry; D014527:Uric Acid / Q000032:analysis; D014822:Vitreous Body / Q000737:chemistry*; D019820:Xanthine / Q000032:analysis
chemical_list: D019820:Xanthine; D014527:Uric Acid; D019271:Hypoxanthine; D006147:Guanine