The Plasma Chemistry Laboratory at CAIS is an analytical geochemistry laboratory specializing in the analysis of trace elements and isotope ratios in biological, environmental, geological, archaeological and other materials.
Cell pellets, proteins, and enzymes are analyzed by solution-based ICP-MS and/or ICP-OES. Digestion solutions containing dilute acids may be submitted. If your samples denature or are unstable at low pH they will need to be digested with concentrated acid and heating. If you plan to digest the samples yourself, please see our Sample Preparation Guidelines. Alternatively, we provide digestion services for these samples. Please contact us if you require digestion, so we can tailor methods to your project.
Cell pellets: The entire contents of the tube will be digested, so cells must be washed so that none of the metal-containing media is present. The tube should be pre-weighed, then weighed again once the liquid has been removed. Pellet masses must be provided on the sample submission form. Please also provide an empty tube for use as a tube blank. We normally request approximately 100 mg of sample, but this can vary depending on the metal(s) of interest (specifically their limits of detection and their expected uptake in your cells). Please contact us if you have small samples and/or want to analyze metals that are not easily taken up by your cells. Note that the 100 mg guideline is for cells that have been pelleted and had the liquid aspirated off. Freeze-drying will result in lower masses for the same number of cells, but is also acceptable.
Proteins & enzymes: A sub-sample of your protein solution will be digested. In order to know what volume you need to send, please let us know what metal(s) you want to measure, the protein concentration (M) and the expected binding stoichiometry (moles of metal per mole of protein) for each metal. The volume required will depend on these factors, as well as the limit of detection for each metal.