David L. Smith, CIH; Michele L. Bolyard, CIH; and Peter M. Eller, Ph.D., CIH

“ The minimum data entered in the notebook should be sufficient to enable another chemist to derive the same results as the original worker, with no other source of information. In addition to this minimum data, any other facts appropriate and pertinent to the sample analysis are to be entered. A chemist's notebook is always subject to inspection by his colleagues, supervisors, or inspectors from outside the laboratory. ”

“ The nature and number of blank measurements will depend on the method and circumstances, but the purpose of all blank measurements is to help prevent errors in identification and quantitation of field samples. [3] d. Blind Samples Blind samples are prepared by someone other than the analyst performing the measurement and are to provide an independent check on the accuracy and precision of the measurement. If blind samples cannot be prepared with confidence, their use should be avoided. ”

“ To accomplish this goal, quality assurance personnel should work closely with laboratory personnel to quickly identify and eliminate trouble spots. It will not always be possible to isolate the source of error in the results of a blind sample. ”

“ The exact sampling time must be known in order to accurately estimate the sampled volume. Recording only the start and stop time assumes that the pump functions properly over the entire sampling period. Occasional spot checks for proper operation should be made throughout the sampling period.
Since many modern analytical techniques are extremely sensitive, special care must be taken to avoid contamination of field samples. [8] Samples must not be stored or shipped with bulk materials which might spill or otherwise present the possibility for contamination. ”

“ Duplicates Duplicate preparations of bulk materials are useful as an indication of the uniformity of the bulk material. Duplicate injections or measurements from air samples are of lesser importance since preparations from air samples are generally uniform in nature. ”

“ This person or group should periodically inspect and repair all equipment and keep track of the use and location of sampling equipment when it is signed out. Sampling pumps should be calibrated with each use. ”