Stable isotope analysis of safety matches using isotope ratio mass spectrometry - a forensic case study

Isotope ratio mass spectrometry (IRMS) was used to assess what contribution the technique could make towards the comparative analysis of matchstick samples within the 'normal' framework of a forensic investigation. A method was developed to allow the comparison of samples submitted as a result of an investigation, with the added advantage of rapid sample turn-around expected within this field. To the best of our knowledge this is the first time that wooden safety matches have been analysed using IRMS. In this particular case, bulk stable isotope analysis carrried out on a 'like-for-like' basis could demonstrate conclusively that matches seized from a suspect were different from those collected at the scene of crime. The maximum delta C-13 variability observed within one box was 2.5 parts per thousand, which, in conjunction with the error of measurement, was regarded to yield too wide an error margin as to permit differentiation of matchsticks based on C-13 isotopic composition alone given that the 'natural' C-13 abundance in wood ranges from -20 to -30 parts per thousand. However, from the delta H-2 values obtained for crime scene matches and seized matches of -114.5 parts per thousand and -65 parts per thousand, respectively, it was concluded that the matches seized were distinctly different from those collected at the crime scene. Copyright (c) 2005 John Wiley & Sons, Ltd.