I. Time to carry out standard method validation

According to Article 4.5.14 of RB/T214-2017, the time for inspection and testing institutions to carry out standard method verification generally includes: (1) verification before using the standard method; (2) re-verification after the standard method is changed verify. The first time is to verify before using standard methods, which is a work carried out by inspection and testing institutions when preparing to apply for qualifications. This verification has the most and most complete standard methods, covering all the applied standard methods. The second time is the verification when the standard method that has obtained the qualification is changed. The premise of this verification is that the standard method included in the qualification obtained by the inspection and testing institution is changed, whether it is a substantial change in the detection capability or only the year number, Any changes in the number need to be verified. Compared with the first standard method verification, this verification is an individual verification of several standard methods.

II. Implementation of Standard Method Validation

To carry out standard method verification, generally from the aspects of personnel, equipment, environmental conditions, inspection and testing consumables, sample extraction, storage and reception, record forms, and result verification.

1. People

The personnel aspect should be verified from the aspects of personnel training quality, personnel quantity, personnel qualification, etc.

(1) In terms of training quality. When carrying out new inspection and testing items, the inspection and testing agency will conduct internal or external training for personnel, and evaluate the training quality after the training. The inspection and testing institutions should assess the degree to which the personnel have mastered the standards; whether the equipment used in operation, maintenance, and period verification are mastered; whether the design of the record form meets the requirements, etc., and if necessary, blind sample assessment or internal personnel comparison can be conducted, etc. Ways to assess the quality of training.

(2) The number of personnel. For the same inspection and testing project, generally at least two inspection and testing personnel are determined to ensure that the inspection and testing work will not be completed on time due to shortage of personnel.

(3) Personnel qualifications. Article 4.2.5 of RB/T214-2017 stipulates that "inspection and testing institutions shall conduct sampling, operating equipment, inspection and testing, issuing inspection and testing reports or certificates, and providing opinions and explanations based on corresponding education, training, skills and experience. Ability confirmation. ” The inspection and testing institution shall confirm the ability according to the training of the personnel, the mastery of the standards, the proficiency of the instruments and equipment, and the skills. Personnel ability confirmation includes confirmation of inspection and testing ability and confirmation of ability to operate instruments and equipment, and form written documents. For some special inspection and testing items, such as wine sensory inspection, it is necessary to obtain the qualification of a sommelier. When determining the qualification of the personnel, it must be confirmed whether the personnel have obtained the corresponding qualifications stipulated by the state.

2. Equipment

The inspection and testing organization should check whether the metrological characteristics (such as measurement range, offset, resolution, drift, etc.) of the configured instruments and equipment meet the requirements in the standard method according to the requirements of the standard method. Secondly, after confirming that the requirements of the standard method are met, check whether the instruments and equipment used have developed a verification, calibration or verification plan, maintenance plan, period verification plan and other plans, and implemented according to the plan. After the verification, calibration or verification of the instruments and equipment, the results after verification, calibration or verification shall be confirmed by metrology to ensure that the instruments and equipment meet the requirements of the standard method.

3. Environmental Conditions

If there are requirements for the inspection and testing environment, sample storage and other environmental conditions in the standard method, the inspection and testing agency should check whether the environmental conditions of the inspection and testing site and the environmental conditions of sample storage meet the requirements. In addition, if the environmental conditions have an impact on the inspection and testing results, the inspection and testing agency shall configure corresponding monitoring equipment to monitor the environmental conditions and make monitoring records. These monitoring equipment should also prepare a verification, calibration or verification plan, and carry out metrological confirmation of the results after verification, calibration or verification to ensure that the monitoring equipment meets the requirements of the standard method.

4. Inspection and testing consumables

Inspection and testing consumables are essential to carry out inspection and testing activities. Each standard method will give which consumables are required. The inspection and testing organization needs to check whether the equipped consumables meet the requirements against the standard method, and conduct acceptance of these consumables. In addition, if it is given in the standard method that the consumables have reference materials or reference standards, the inspection and testing organization should give priority to using certified reference materials or reference standards.

5. Sample extraction, storage and receipt

Sampling is the first step in the inspection and testing work. Whether the sample is representative and whether the storage and receiving process meets the requirements of the standard method directly affects the validity of the inspection and testing results. Therefore, the inspection and testing organization should strictly follow the standard method. The requirements for sample extraction, storage, and receipt in the Verification Agency are checked whether the requirements are met. For example, GB/T 5750.2-2006 "Standard Test Methods for Drinking Water: Collection and Preservation of Water Samples" for the collection and preservation of drinking water includes the selection of sampling containers, washing of sampling containers, water sample collection, sampling volume and different inspections. The material and storage method of the container used for project sampling, the filtration and centrifugation of water samples, the storage conditions of water samples for different inspection items, and the transportation of water samples have been stipulated in detail. The project is compared with GB/T5750.2-2006 to check whether the organization can meet the requirements of GB/T5750.2-2006.

6. Record Form

Records are evidence that the inspection and testing process is effective. The inspection and testing organization shall check whether the information recorded in the record form is sufficient; whether the content recorded in the record form is complete and traceable; whether the record form is standardized and meets the organization's requirements for records. Check whether the typical report issued meets the relevant standards and the agency's requirements for the inspection report. If there is a requirement for uncertainty in the standard, it should also check whether the uncertainty report is reasonable and whether the uncertainty source analysis is comprehensive.

7. Result verification

After verifying the standard method in terms of personnel, equipment, environmental conditions, etc., the inspection and testing agency shall then verify the results. Result verification can be carried out at the same time as the blind sample assessment in the personnel training assessment or the internal personnel comparison of the institution. Some standards put forward specific requirements on the quality control of results, and inspection and testing institutions should carry out result verification in accordance with the provisions in the standards. For example, GB/T5750.2-2006 proposes various quality control methods such as field blank, transportation blank, field parallel sample, field spiked sample or quality control sample for the quality control of drinking water. .2-2006 to carry out quality control work and verify results.

The inspection and testing institutions do a good job in the verification of the standard methods, which provides a guarantee to ensure that the inspection and testing reports issued are accurate and reliable.