School of GeoSciences

ICP-OES and ICP-MS

Inductively Coupled Plasma Optical Emission Spectrometry and Inductively Coupled Plasma Mass Spectrometry

 

Introduction ICP-OES:

ICP-OES (Inductively Coupled Plasma Optical Emission Spectrometry) is a fast multi-element technique with a dynamic linear range and moderate detection limits (~0.2-100 ppb). The instrument uses an ICP source, made by ionizing argon gas, to dissociate the sample into its constituent atoms or ions, exciting them to a level where they emit light of a characteristic wavelength. Up to 60 elements can be screened per single sample run of less than one minute.

Introduction ICP-MS:

ICP-MS (Inductively Coupled Plasma Mass Spectrometry) is a multi-element technique for trace analysis where low detection limits (0.0005-1.0 ppb) are required and for high-precision isotope ratio studies. The plasma source is an excellent ion source and most elements from 0-240 amu are ionised into singly charged positive ions (M+ ). Sample preparation is more crucial than in ICP-OES with samples ideally dissolved in 2% HNO3 v/v, a total dissolved solids content

 

The facility can be divided into 3 parts:

  1. The sample preparation lab (room 225)
  2. The ICP-OES lab (room 235)
  3. The Brian Price ICP-MS lab (room 241)

 

  1. Room 225: The samples destined to be analysed by ICP OES/MS are prepared in the clean lab room 225. This is a trace metal clean laboratory equipped with 2 laminar flow benches, 2 extracting eco-power fume hoods, an acid distillation system, hot plates and a micro balance. The rock, sediment, soil or plant samples to be analysed are digested on a hot plate using clean concentrated acids. The calibration solutions are also prepared in this lab and the standards are kept in a ventilated cabinet in the lab. The digested samples are diluted to required concentration range and/or purified via ion exchange resin column chemistry in the clean lab prior to analyses by ICP-OES or ICP-MS. All users have access to the clean lab providing they have had the appropriate training and health and safety tour of the lab by the facility manager or alternatively Dr Alex Thomas.

 

  1. Room 235: The Inductively Coupled Plasma-Optical Emission Spectrometer (ICP-OES) Lab is equipped with a Laminar Flow bench and a Vista Pro ICP-OES. Final sample preparation steps are done in the laminar flow bench. The ICP-OES technique provides quantitative bulk elemental (major and trace) composition of rock, water or soil samples at concentrations ranging from ppm to ppb. Analyses of trace and redox sensitive elements in sediments and of contaminants in soil and plants are common examples of ICP-OES applications.

 

  1. Room 241: The Brian Price ICP facility is equipped with a high resolution Inductively Coupled Plasma-Mass Spectrometer (AttoM, HR-ICP-MS) and a multi-collector Inductively Coupled Plasma- Mass Spectrometer (Plasma II MC-ICP-MS). Both instruments can be coupled to a Laser ablation system for analysing non-dissolved samples (e.g. rocks, shells). The AttoM provides rapid and precise isotope ratio and quantitative analysis of trace elements in solid (with Laser ablation) and liquid phases at concentration below ppm levels. For more demanding isotopic ratio measurements and some specific applications (Si and Fe isotopes), the plasma II MC-ICP-MS is used.

 

For further information on all aspects of the ICP facility including digestion and laser ablation please contact Laetitia Pichevin: laetitia.pichevin@ed.ac.uk

 

The Technical Request Form for ICP can be found here.