University of Otago, New Zealand

Chemistry

Te Tari Hua-Ruanuku

Otago forensic chemistry expertise used in 1080 milk powder case

Monday 18 April 2016

It was a crime that shook New Zealand to the core — the horrific threat to poison baby milk powder with 1080 pesticide. And it recently resulted in a lengthy jail term for an Auckland businessman, with help from the University.

Prof Russell Frew and Dr Robert Van Hale

What many may not know is that some of the forensic evidence gathered in the Police investigation was provided by the Isotrace Research Unit in Otago’s Department of Chemistry.

Professor Russell Frew, who heads Isotrace, prepared a report for the Police based on the Unit’s analysis of the stable isotopic composition of the 1080 in the two milk powder-containing letters sent to Fonterra and Federated Farmers and of 43 other samples of 1080. These samples represented all known sources of the chemical in New Zealand.

Professor Frew says that comparing ratios of isotopes is a particularly good way to distinguish different sources of the same chemical substance.

Essentially we can identify isotopic ‘fingerprints’ that indicate whether various samples came from the same or different production batches, for example.

The analysis they were asked to carry out on the 1080 was more complicated than those Isotrace had previously carried out on methamphetamine samples, he says.

As there were only trace amounts of 1080 mixed with milk powder, Unit member Dr Robert Van Hale first had to carry out a pilot study to confirm that they could process these two samples in such a way that they could be accurately analysed.

After this was confirmed, analysis of the 43 samples and the 1080 from the letters went ahead. With the assistance of Professor Richard Barker and Dr Matthew Schofield of the Department of Mathematics and Statistics, the team was able to determine that five samples stood out strongly from the rest. While the other 38 could be eliminated, these five could not be characterised as distinctly different from the letter 1080.

Read the full story via the Otago Bulletin