Elemental
Spectrometry Facility
The instrumentation of the Elemental Spectrometry Facility at AAC includes an Inductively Coupled Plasma Optical Emission Spectrometer, an Inductively Coupled Plasma Mass Spectrometer, a laser ablation ICP-Mass spectrometer (multi-collector system) and a mercury analyser. These instruments provide elemental analysis from concentrations of weight percent down to lower than parts per billion for most of the elements in the periodic table. They are typically solution-based (except when using the laser ablation system), hence samples need to be dissolved before analysis if they are not already in liquid form. This is normally accomplished by open vessel, microwave-assisted digestion or, where necessary, by fusion. The Elemental Spectrometry Facility is suitable for a wide range of materials including geological, biological and environmental.
Inductively Coupled Plasma - Mass Spectrometer (ICP-MS)
The Varian ICP-MS 820 is a quadrupole based instrument, and is a fast and sensitive technique for multi-element analysis. Sample solution is introduced to ICP through a nebulizer combined with a spray chamber and then through a pair of sampler and skimmer cones. The resulted ions are extracted into a quadrupole which works as a mass filter, then detected and processed to generate a final concentration results. ICP-MS provides quantitative analysis for most of the elements of the periodic table and is particularly suitable for trace and ultra-trace levels (equivalent to parts per million to sub-parts per billion). The centre routinely analyses wide range of samples
Inductively Coupled Plasma - Atomic Emission Spectrometer (ICP-AES)
ICP-AES is a well-established and cost effective technique for multi-element analysis. The AAC operates a Varian Liberty Series II, which is a sequential instrument. Like ICP-MS, the sample is introduced into the plasma by a nebulizer and a spray chamber and atoms (or ions) are generated and elevated to excited states. They then "relax" to a lower excited or ground state, and in the process emit radiation at characteristic wavelengths. A spectrometer is used to separate the light emitted and is detected using a photo multiplier tube (PMT). ICP-AES is best suited for elements in the low weight percent to parts per million concentration range. The Centre performs analysis on a variety of materials.
High resolution, Multicollector Inductively Coupled Plasma - Mass Spectrometer (MC ICP-MS)
The Neptune MC ICP-MS operates in a similar way to the other ICP techniques with samples introduced via a spray chamber to a plasma resulting in the ionisation of the constituent elements. Rather than determining the absolute abundance of elements present the high resolution multicollector mass spectrometer is used for the precise measurement of isotope ratios (for example as used in isotopic dating techniques).
Excimer Laser Ablation
Along with the Neptune MC ICP-MS, a new addition to the instruments available is the GeoLas 200 Excimer Laser Ablation System. Using a short wavelength (193nm) laser, a wide range of solid material types can be sampled using spot sizes from 160 to 5 microns. The ablated material can be introduced directly to either the ICP-MS or MC-ICP-MS allowing for in-situ elemental or isotopic micro-analysis. Thus, rather than analysing "bulk" sample compositions, small areas (such as individual mineral grains) can be analysed directly from the solid material.
Sample Preparation
Sample preparation methods to prepare samples for analysis include
- Lithium Metaborate fusion
- Microwave bomb digestion
- Open Vessel Digestion
- Digestions using HF
Applications Laboratory
The centre is an application laboratory for Varian in the areas of ICP-MS and ICP-AES.
| For all general enquiries contact - Dr Kevin Blake |
| Email: kevin.blake@jcu.edu.au |
| Phone: (07) 47 81 4864 |
| Fax: (07) 47 81 5550 |
