Isotope and elemental analysis guide

Introduction

The Environmental Biology Group, within the Research School of Biological Sciences at The Australian National University willingly accepts organic samples for stable isotope analysis from other groups and individuals. While the bulk of the material is of plant origin, animal samples can also be analysed. We specialise in oxygen isotope analyses of organic matter [see Farquhar G.D.,Henry B.K.,and Styles J.M.(1997). A rapid on-line technique for determination of oxygen isotope composition of nitrogen-containing organic matter and water. Rapid Communications in Mass Spectrometry, 11(14): 1554-1560] and also conduct carbon, nitrogen and hydrogen isotope analyses; as well as elemental analyses of carbon, nitrogen, and hydrogen (as water) and oxygen (in pyrolysis mode).

Carbon, nitrogen, hydrogen and oxygen isotopic analysis

We regularly analyse organic materials and water for carbon, nitrogen, hydrogen and oxygen isotopes, as appropriate. Carbon and nitrogen are determined via Dumas combustion while hydrogen and oxygen of organic materials is prepared by pyrolysis. Water is pyrolysed for oxygen isotope analysis but usually reduced over chromium for hydrogen isotope studies. A table of prices is given below but we are somewhat flexible depending on the number of samples and the nature of the project, including our rôle in it. Processing time varies according to the type of analysis and the size of the batch of samples. On average the turnaround time for a batch of 100 samples is approx. 4-6 weeks from time of arrival.

Elemental analysis

We analyse elemental abundance by Dumas combustion, with oxidation of carbon and hydrogen to carbon dioxide and water respectively. Nitrogen is analysed as diatomic nitrogen gas. These operations may be performed either separately on an elemental analyser or in parallel with isotopic analysis of carbon and nitrogen. Oxygen is always analysed on the high temperature pyrolysis unit. These prices vary according to the type of project and our rôle in it. .

Sampling

Different parts of plants often yield different delta values and it is important to take this into account when sampling. Plant to plant variation also occurs, and combining, for example, ten plants will usually reduce the variation among samples to near the level of precision of the mass spectrometric analysis. Alternately, statistical analysis will indicate true treatment means.

For animal samples, muscle tissue is used most commonly, taking care to avoid the inclusion of bone material which may bias the result.

It is important that the sampling procedure is standardised within a project. We advise customers to include a few replicate samples with each batch submitted in order to gain some idea of the variability which can be seen within the samples, usually as a result of inhomogeneity.

Grinding

Each sample should be oven dried at 85 E C for 16 hours and ground to a maximum particle size of 0.1mm. We grind our samples in a Cyclotec model 1093 grinder with a 0.4mm screen. Please aim to supply us with at least 50mg of homogenous sample.

Packaging

• Each sample should be contained in a well identified glass scintillation vial.
• We require that samples are clearly marked using 4 to 8 character alphanumeric identifiers.
• Consecutive numbers make it easier for identification and data handling.
• Please do not send samples in plastic containers as the static charge which builds up prevents easy handling. Plastic containment will also prevent oven treatment, upon which basis we may refuse to accept samples.
• Vials should be separated from each other and padded to prevent breakage.
• Parcels can be sent through the normal mail system and addressed to:-

Research Officer - Stable Isotopes

Environmental Biology Group

Research School of Biological Sciences

The Australian National university

GPO Box 475

Canberra ACT 2601

Australia

The box must be clearly marked "Dried Plant Material for Analysis - No Commercial Value". This will speed their journey through Australian customs and quarantine.

• Please do not send using special courier services. Samples sent this way will be held in quarantine, and in such instances extra cost will be incurred for their release.
• Please include in the parcel your name, address, and a brief description of the experimental work, and a list of the material sent.
• Note that material will be destroyed 90 days after the results have been sent out, to comply with Australian quarantine regulations.
• A charge will be levied for returning samples.
• AQIS will irradiate all samples sent from overseas.  Currently the charge/s are between $42.50 and $100 per package.  These charges will be levied on your invoice.

Payment

Private / Corporate / Government Customers

A purchase order, or email authorising the work, should either precede or accompany any samples sent to us. We will then send you an invoice raised against the order/email. Payment can be made by cheque, bank transfer or credit card (as detailed on the invoice).

Within the ANU

An email, with full contact details, authorising the work should precede or accompany any samples sent to us.  Payment will be arranged via an internal journal entry and a charge code is required before samples will be analysed.

Prices

Please note:  we invoice in Australian dollars only.

Details of duplication and replication etc can be discussed. Typically prices include the necessary standards (at least 2 different standard materials per run) and sample repetition for precision assessment. In general we prefer to be provided with ground material and we will perform all weighing and pellet production.

Enquiries

Please direct enquiries to Isotopes either at the above address or by telephone on 61 02 6125 4407, or fax on 61 02 6125 4919, or by email to isotopes@rsbs.anu.edu.au . Enquiries may also be sent to Dr Hilary Stuart-Williams at 02 6125 2099 (mobile 0421 905 478) or hilary@rsbs.anu.edu.au . We will try to answer all questions within one working day.

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