Summary• Stable isotope ratios of organic compounds are valuable tools for determining the geographical origin, identity, authenticity or history of samples from a vast range of sources such as sediments, plants and animals, including humans.• Hydrogen isotope ratios ( δ 2 H values) of methoxyl groups in lignin from wood of trees grown in different geographical areas were measured using compound-specific pyrolysis isotope ratio mass spectrometry analysis.• Lignin methoxyl groups were depleted in 2 H relative to both meteoric water and whole wood. A high correlation ( r 2 = 0.91) was observed between the δ 2 H values of the methoxyl groups and meteoric water, with a relatively uniform fractionation of -216 ± 19‰ recorded with respect to meteoric water over a range of δ 2 H values from -110 in northern Norway to + 20‰ in Yemen. Thus, woods from northern latitudes can be clearly distinguished from those from tropical regions. By contrast, the δ 2 H values of bulk wood were only relatively poorly correlated ( r 2 = 0.47) with those of meteoric water.• Measurement of the δ 2 H values of lignin methoxyl groups is potentially a powerful tool that could be of use not only in the constraint of the geographical origin of lignified material but also in paleoclimate, food authenticity and forensic investigations.

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 delta13C variability observed within one box was 2.5 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 13C isotopic composition alone given that the 'natural' 13C abundance in wood ranges from -20 to -30 per thousand. However, from the delta2H values obtained for crime scene matches and seized matches of -114.5 per thousand and -65 per thousand, respectively, it was concluded that the matches seized were distinctly different from those collected at the crime scene.

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