Problems needing attention in sampling and sampling during on-site review of CMA/CNAS certification

Date：2022-12-20 14:59:00Views：677

1. Sampling and testing, operation process

Contract review, on-site exploration (if necessary) and contract signing. Select the sampler (at least 2 people, who shall work with certificates). Formulate sampling plan (to be reviewed and approved). Preparation of sampling supplies. On site sampling (observe for four weeks, record the time, place and environment, and start sampling, recording, sealing, packing, loading and returning to the laboratory). Packed and returned to the laboratory. testing. Results report.

2. Sampling related procedure documents

A procedure document is required for sampling. No sampling is required, and the contents related to sampling can be specified in the operation instructions. Sampling and sampling are the same in English, but they have different meanings in our country. Sampling: It refers to collecting several samples from a large number of samples or a whole, such as river water sampling and soil sampling. Sampling: a part of the collected samples is taken as samples for testing. For example, the customer sent 200g of soil to test the content of heavy metals, while the laboratory only took 0.5g for testing.

3. What are the on-site sampling supplies?

Sampling tools, sample containers, stabilizers, spiked solutions, sample storage tools, sample labels, sampling records, pens, environmental monitoring equipment, cameras, GPS locators, electronic scales, emergency medical kits, safety protection supplies, transportation tools, fire extinguishers (if necessary), etc.

4. What quality control measures should be taken for sampling?

Sampling and transportation blank, on-site parallel sample, on-site plus standard sample, password sample. Code sample: take two samples of the same type, but have different numbers to prevent special treatment by the tester.

5. Content of original sampling record

Samples in different fields are quite different, usually including: sample name, sample number, sampling location/position, sampling time, sampling method, sample properties, sampling volume, container, storage requirements, sampler, environmental conditions, etc.

6. Use label content

Samples in different fields are quite different, usually including sample name, number, sampling location, sampling time and sampler.

7. Does sampling belong to mobile site inspection?

If it is a sampling inspection vehicle, it can be considered as a moving place. If it is only a portable testing instrument, it is not easy to define it as a mobile place. The on-site inspection during the customer's on-site sampling does not belong to a fixed place, so the environmental conditions must be monitored and recorded to ensure that the inspection requirements are met.

8. How to conduct method validation for sampling?

It can only be practiced several times. Necessary tools are required, and tools and previous records will be checked. In some areas, no sampling qualification is given, and the laboratory samples itself for testing, which can be stamped with a label. Qualification is given in some areas, and only sampling of detectable items is allowed.

9. One sample contains 10 individual packages. Take one of them for testing, is it sampling?

Theoretically, it is sampling. Operation method: The whole sample has one number, such as ASDFG, and each sub sample is from ASDFG-01 to - 10. The laboratory can choose one of them for testing, and the customer can designate one to test, or mix several, which should be accurately recorded.

10. Precision and accuracy verification in field sampling method verification

If the detection method does not include sampling, sampling will not be considered. The test standard is independent, and the sampling part can be assessed separately. If sampling is described in detail in the test method, but the laboratory is not responsible for it and does not need to verify it. If sampling is described in detail in the testing method, and sampling and testing cannot be separated, they can only be verified together.

11. Precautions on sampling site

Smoking is prohibited. Any accident should be reported and protective clothing must be worn. If necessary, goggles must be worn and protective clothing must be worn. Work gloves must be worn. The location of alarm systems and fire-fighting equipment must be known. The operator must be able to operate and use food and drink at the sampling site that is not in a harsh environment to prevent sample contamination.