ICP-AES Testing

Inductively Coupled Plasma – Atomic Emission Spectroscopy (ICP-AES)

Inductively Coupled Plasma – Atomic Emission Spectroscopy (ICP-AES) also known as Inductively Coupled Plasma – Optical Emission Spectroscopy (ICP-OES), measures element-specific spectra emitted from atoms and atomic species in a heated in plasma.  Galbraith Laboratories commonly employs ICP-AES to measure Group I metals, Group II metals, Transition metals, Metalloids (such as boron, silicon, germanium, etc.) and some Non-Metal elements (such as sulfur and iodine) in a wide variety of sample matrices.

Preparation

Each successful analysis begins by adequately digesting the sample for the analysis.  The final outcome of each preparation is to afford a homogenous solution of the analyte in the analysis solvent.  In most cases, the analysis solvent is water that is stabilized with acid.

Analysis

Sample solutions are infused into the ICP instrument by way of a peristaltic pump.  The solution is nebulized into an aerosol that is transported to a plasma torch.  Metal ions in the sample solution are subjected to intense heat in a radio-frequency inductively coupled argon plasma.  The elements emit characteristic spectra which are separated by a grating.  The intensity of the emission lines are monitored by a photosensitive device.  Metal ion concentrations of unknown samples are determined by comparison to an external calibration of the instrument.

Method

Galbraith’s general method was written from nationally accepted methods, such as EPA SW846 6010B.  It also meets the general guidance of USP <730>.  Click below to view a copy of the method summary:

ME-70-Rev-8-ICP-AES-GLI-Method-Summary

For information on Galbraith’s USP <232> and <233> services, click here.

Quantitation Limit

Unless otherwise evaluated, the quantitation limit (QL) depends on the concentration of the lowest calibration standard used to calibrate the instrument.  Results that read below the QL are reported as less than values, i.e <0.5 ppm.

Results

Results are calculated using the mass of sample originally taken for the analysis.  For example if 250 mg of sample is dissolved in 25 mL of water and the solution reads 0.1 mg/L, then the final result is 0.1  x 25 / 0.25 or 10 ppm.

Typical reporting units are ppm, mg/L or %.  Other units may be reported. Regulated Submissions

The general methodology is suitable for the analysis of regulated samples.  The method is considered validated to a reference substance, but not to the sample matrix unless a formal validation is conducted.  Click here to see more information on Method Validation.