An environmental sampler is configured to deliver a pre-determined volume of external environmental sample and internal standard sample to the mass spectrometer on each cycle of advancing and retracting movement of a sampler rod under control of a stepper motor. Each paint is kept in a ceramic cup which is kept in a water reservoir such that the cup wicks the moisture from the reservoir. The key storage unit may receive and store calculation key data items or storage key data items as input key data items, and may output the stored input key data items as the storage key data items.