The content of the elements N, C, H, S, and O in sample material can be determined by elemental analyses.

DB Lab has two Carlo Erba elemental analysers.

Determinations of N by elemental analyses have been validated with reference to the Kjeldahl N determination.

DB Lab has equipment for determination of total organic carbon (TOC), non-volatile organic carbon (NVOC), total carbon (TC), inorganic carbon (IC) and total nitrogen (TN) in water solutions. Detection limits for pure water samples are below 50 ppb.

TOC is used on routine basis for examination of pure water according to the Ph. Eur. and USP.

TOC eventually combined with TN is generally very useful in cleaning validations.

Certain cleaned areas are swabbed using glass-fibre swabs that do not contain any organic carbon or nitrogen. The swabs can be extracted with pure water and the content of organic carbon determined. It is possible to combine the carbon analyses with a nitrogen analyses and thus get extra information about impurities that might be present on the swabs.

DB Lab has equipment for determination of TIC (total inorganic carbon) in gels and solid substances like powders. The inorganic carbon can be carbon dioxide, carbonic acid, bicarbonate (hydrogen carbonate) and carbonate. Samples are transferred to a closed flask and acidified with phosphoric acid. The acid conditions ensures that the inorganic carbon is converted to the carbon dioxide form. Carbon dioxide is led by a carrier gas (synthetic air, nitrogen or oxygen) to an infrared detector.

Gels can be acidified by uptake of carbon dioxide from the atmosphere.