Certificates of Analysis Explained
Certificate of analysis guide
NOTE 1: Long term storage Unless otherwise stated, storing reference materials in pure organic solvent at temperatures below those specified is not detrimental. Some analytes may come out of solution at lower temperatures and so the reference material should be warmed to room temperature and mixed prior to use. Products in aqueous solvent should not be stored at temperatures below 0°C unless explicitly stated.
NOTE 2: Uncertainty In accordance with the Guide to the Expression of Uncertainty in Measurement (GUM), our certificates of analysis list the expanded concentration uncertainty at the about 95 % level of confidence using a coverage factor of k = 2. They incorporate uncertainty of the purity, material density and balance and weighing technique. Our concentration uncertainties are valid in the range between 19°C and 25°C.
NOTE 3: Expiry Date (Retest date) We run "accelerated stability studies" backed up with additional stability testing at regular time points after initial production - "real time stability tests". From the data obtained during these investigations, we determine the ideal long-term storage conditions of our reference materials. Additionally the stability of every lot is regularly investigated through a routine quality control testing program. These results can be used to reassign expiry dates and on occasion may lead to changes in the storage temperature.
NOTE 4: Concentration The concentration is based on gravimetric material weighings - using weights traceable to SI units - and material purity factor (assay of the neat material). The concentration listed is 'as is' for neat materials or 'free base/acid' for salt forms, meaning no further correction is required.