Laboratory Testing – Technical

We can store samples under ambient (15 to 25), refrigerated (2-8) and frozen (-15 to -25) conditions. Please specify the conditions you require on your sample submission form. If no conditions are indicated on your form, we will store your samples under the condition in which they are received.

Elemental impurities could relate to many forms of testing; however, in the context of pharmacopoeias and ICH guidelines, it relates to testing the 24 key risk metals to limits related to the expected daily dose and use to ensure the final product is safe.

Both systems use plasma to excite and/or ionise elements in a solution for analysis (ICP = Inductively coupled plasma).
An ICP-OES uses a photometer to measure light emissions, which are characteristic of the element and relative in intensity to the concentration in the solution.
An ICP-MS measures the mass/charge ratio of ions to give a direct determination of concentration.
An ICP-MS is generally several orders of magnitude more sensitive than an ICP-OES; however, this can vary by element. An ICP-OES is more able to handle strong matrix solutions compared to an ICP-MS

These terms can be used interchangeably; however, there is a difference. Osmolarity (or osmotic concentration) measures solute concentration by volume, while osmolality measures concentration by weight. The density of a solution can be used to convert from one to the other.

There are many ways to prepare samples for ICP-MS analysis; the best method will depend on the sample type and elements that are required to be measured. If possible, dilution in dilute acid is the best preparation method as it requires fewer steps and so reduces any chance of contamination or matrix effects when measuring the solution. This will not always be possible however, especially for organic samples, the most common preparation for such samples is microwave digestion.
Whatever method is used, it is important that dissolution is complete and a clear solution is obtained to ensure accurate determination.

There is no practical difference; both are indirect measurements of viscosity. Direct measures of viscosity include measuring using a U-tube, such as a Ubbelohde viscometer.