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Draft 6. Note: This document is a draft suggestion only and is not an approved document.
Please do not distribute to laboratory staff for use.
available, or laboratory determined expiration date, and traceability to the person assuming responsibility for the
chemical Reference Material. For further guidance, refer to APLAC TC012-09/10, “Guidelines for acceptability of
chemical reference materials and commercial chemicals for calibration of equipment used in chemical testing.”
Reference Materials shall not be used past their expiry date without requalification demonstrating that they are still
suitable for use.
If possible, Reference Materials shall be obtained from Reference Material producers accredited to ISO Guide 34,
"General requirements for the competence of reference material producers."
5.7 Sampling and Sub-Sampling
Most laboratories do not sample materials outside the laboratory. When the laboratory has not been responsible for
the sampling stage, it may be appropriate to state in the report that the samples were analyzed as received. The
customer selects samples in the vast majority of cases. In cases where the laboratory is required to conduct field
sampling of products, they shall comply with established procedures for those programs (for example, the Meat
Importers Council of America sampling plan for fat testing) and these requirements.
Most laboratories do not test the entire sample as received, but instead perform testing on a sub-sample (portion,
aliquot, etc). The laboratory shall have documented procedures for sub-sampling, compositing, and/or
homogenization to ensure that a representative test portion is used for analysis.
Note
: Whatever strategy is used for the sampling, it is of vital importance that the sampler keep a clear record of the
procedures followed in order that the sampling process may be repeated exactly and that the analytical result is
traceable to the lot it represents. Routinely used sampling procedures should be fully documented. “In some
circumstances, for example where samples have been taken for legal purposes, the sample may be sealed so that access
to the sample is only possible by breaking the seal. Confirmation of the satisfactory condition of the seals will
normally form part of the analytical report.” [
CITAC/Eurachem Guide to Quality in Analytical Chemistry: An Aid to
Accreditation
(2002)]
Note
: Appropriate considerations should be made for multi-phase and labile samples, aseptic handling,
cross-contamination, and other issues to reduce the known errors associated with sample heterogeneity. “If the
laboratory has conducted or directed the sampling stage, it should report on the procedures used and comment on any
consequent limitations imposed on the results.” “Where more than one sample is taken from the original material it
may be useful to include a diagram as part of the documentation to indicate the pattern of sampling. This will make it
easier to repeat the sampling at a later date and also may assist in drawing conclusions from the test results.”
[
CITAC/Eurachem Guide to Quality in Analytical Chemistry: An Aid to Accreditation
(2002)]
5.8 Handling of Test and Calibration Items
5.8.1
Storage areas shall be kept clean and organized so there is minimized risk of contamination or
cross-contamination. The samples shall be stored in such a way that the packaging, and/or any related seals are not
damaged. Adverse extremes of environmental conditions shall be avoided.
A checklist detailing the sample storage procedure can be used to ensure all necessary steps are taken to store the
sample correctly. Adverse storage conditions might change the composition of the sample, for example, causing loss
of analyte through degradation or adsorption. If necessary, environmental monitoring shall be used. An appropriate
level of security shall be exercised to restrict unauthorized access to the samples.
5.8.2
Labeling shall be firmly attached to all of the sample portions packaging and, where appropriate, be resistant
to fading, autoclaving, sample or reagent spillage, and reasonable extremes of temperature and humidity.
Note
: Sample labeling is particularly important as a sample progresses further into the analytical process where the
sample may be divided, subsampled, or modified in some way. In such instances, additional information may be
appropriate, such as references to the main sample, and to any processes used to extract or subsample the sample.
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