Evaluation method of standard substance in field of environmental monitoring

Abstract

The embodiment of the invention provides an evaluation method for a standard substance in the field of environmental monitoring, which comprises the following steps: testing a to-be-evaluated standard substance, and determining an actually measured concentration value of a target component in the to-be-evaluated standard substance; obtaining a nominal concentration value of a target component in the to-be-evaluated standard substance; calculating a concentration error between the actually measured concentration value and the nominal concentration value, and judging whether the concentration error is greater than a predetermined first judgment index, the first judgment index being determined according to an adding standard recovery rate error, a quality control sample measurement result concentration error and a maximum allowable error of a standard concentration point in an environmental monitoring analysis method; and under the condition that the concentration error is greater than the judgment index, judging that the to-be-evaluated standard substance does not meet the quality requirement of environmental monitoring evaluation. As the first judgment index is determined according to an environmental monitoring analysis method, whether the standard substance to be evaluated meets the environmental monitoring evaluation quality requirement or not is determined by adopting the first judgment index and the actually measured concentration value and the nominal concentration value of the standard substance to be evaluated.

Description

Technical Field

[0001] The present invention relates to the field of standardized monitoring technology, and in particular to an evaluation method for standard substances in the field of environmental monitoring. Background Art

[0002] Reference materials are materials or substances used to calibrate equipment, evaluate measurement methods, or assign values ​​to materials. They are indispensable tools for measurement process control and measurement result evaluation, and are the material basis and guarantee for establishing a consistent and comparable measurement mutual recognition system. Reference materials for environmental monitoring are standard materials used in equipment and evaluation of measurement methods in the field of environmental monitoring. They have an important impact on the concentration measurement of pollutant samples obtained by environmental monitoring, so their composite evaluation is particularly important. However, the current evaluation of the quality value of environmental monitoring reference materials is mostly the evaluation of the accuracy of the quality value of the reference materials by the manufacturer, which lacks objectivity and accuracy. Summary of the invention

[0003] In order to solve the problem that existing environmental monitoring standard materials lack reasonable evaluation indicators and cannot objectively evaluate the usability of environmental monitoring, the embodiments of the present disclosure provide an evaluation method for standard materials in the field of environmental monitoring.

[0004] In a first aspect, the present disclosure provides an evaluation method for standard substances in the field of environmental monitoring, comprising:

[0005] Testing the standard substance to be evaluated to determine the measured concentration value of the target component in the standard substance to be evaluated; and obtaining the nominal concentration value of the target component in the standard substance to be evaluated;

[0006] Calculating the concentration error between the measured concentration value and the nominal concentration value, and judging whether the concentration error is greater than a predetermined first determination index, wherein the first determination index is determined according to the spiked recovery error, the concentration error of the quality control sample measurement result, and the maximum allowable error of the standard concentration point in the environmental monitoring analysis method;

[0007] When the concentration error is greater than the determination index, it is determined that the standard substance to be evaluated does not meet the quality requirements of environmental monitoring evaluation.

[0008] Optionally, the calculating a concentration error between the measured concentration value and the nominal concentration value includes:

[0009] C d -C s

[0010] Using C s Determine the concentration error, where C d is the measured concentration of the target component in the standard substance to be evaluated, C s is the nominal concentration value of the target component in the standard substance to be evaluated.

[0011] Optionally, the environmental monitoring and analysis method includes a sample spike test; the method further includes:

[0012] The method further comprises: using a higher-grade substance to perform a spike test on the standard substance to be evaluated to obtain a corresponding spike recovery rate;

[0013] Determine whether the spiked recovery rate meets the recovery rate standard range in the environmental monitoring analysis method;

[0014] When the spiked recovery rate does not meet the recovery rate standard range, it is determined that the standard substance to be evaluated does not meet the quality requirements of environmental monitoring evaluation.

[0015] Optionally, the method further comprises: determining whether the standard substance to be evaluated has an interfering component based on a product quality report of the standard substance to be evaluated, wherein the interfering component is a component other than the target component that has an impact on environmental monitoring and evaluation;

[0016] In the case where the standard substance to be evaluated has an interfering component, determining a quantitative measurement method for the interfering component based on the material properties of the target component and the interfering component;

[0017] Determining the measured concentration data of the interfering component by using the quantitative measurement method;

[0018] Based on the measured concentration data of the interfering component, determine whether the standard substance to be evaluated meets the quality requirements of environmental monitoring evaluation.

[0019] Optionally, the standard substance to be evaluated is a standard substance having a volatile component; the method further comprises:

[0020] Test different batches of the standard substances to be evaluated separately to determine the actual measured concentration values ​​of the target components in each batch of the standard substances to be evaluated;

[0021] Determine whether the measured concentration value of the target component in the standard substance to be evaluated meets the consistency evaluation index;

[0022] When the measured concentration value of the target component in the standard substance to be evaluated does not meet the consistency evaluation index, it is determined that the standard substance to be evaluated does not meet the quality requirements of environmental monitoring evaluation.

[0023] Optionally, when testing the standard substance to be evaluated, determining the measured standard uncertainty of the target component in the standard substance to be evaluated;

[0024] The method further comprises: testing a higher-level standard substance to determine a measured concentration value and a measured standard uncertainty of a target component in the higher-level substance;

[0025] Before calculating the concentration error between the measured concentration value and the nominal concentration value, the method further includes:

[0026] Calculate the normalized deviation based on the measured concentration value and the measured standard uncertainty of the standard substance to be evaluated, as well as the measured concentration value and the measured standard uncertainty of a higher-level standard substance;

[0027] When the absolute value of the normalized deviation is greater than 1, it is determined that the standard substance to be evaluated does not meet the quality requirements of environmental monitoring evaluation.

[0028] Optionally, the standard substance to be evaluated and the higher-level standard substance are tested in at least two testing laboratories to determine the measured concentration value and the measured standard uncertainty of the corresponding target component, and calculate the corresponding normalized deviation;

[0029] The method further comprises: obtaining an average of the absolute values ​​of the normalized deviations;

[0030] When the absolute value of the normalized deviation is greater than 1, determining that the standard substance to be evaluated does not meet the quality requirements of environmental monitoring evaluation includes: when the average value is greater than 1, determining that the standard substance to be evaluated does not meet the quality requirements of environmental monitoring evaluation.

[0031] Optionally, before at least two testing laboratories test the standard substance to be evaluated and the higher-level standard substance, the method further comprises:

[0032] The higher-level reference materials are tested by two testing laboratories to determine the measured concentration values ​​of the target components and the corresponding expanded uncertainties;

[0033] based on Whether it is established to determine whether the test methods of two laboratories are equivalent, is the measured concentration value of the first laboratory, is the measured concentration value of the second laboratory, is the expanded uncertainty of the concentration value measured in the first laboratory, is the expanded uncertainty of the concentration value measured by the first laboratory;

[0034] In the case where the testing methods of two laboratories are equivalent, the step of testing the standard substance to be evaluated and the higher-level standard substance in at least two testing laboratories is performed.

[0035] Optionally, the standard substance to be evaluated and the higher-level standard substance are both gaseous substances;

[0036] Before at least two testing laboratories test the reference material to be evaluated and the higher-level reference material,

[0037] The test instrument is purged with high-purity inert gas for at least a first set time, and then the test instrument is purged with the to-be-tested standard substance or the higher-grade standard substance for at least a second set time.

[0038] Optionally, the operation of testing and calculating the normalized deviation is performed at least twice within the calibration validity period of the standard substance to be evaluated;

[0039] The method of determining that the standard substance to be evaluated does not meet the quality requirements of environmental monitoring evaluation when the absolute value of the normalized deviation is greater than 1 includes: when at least one absolute value of the normalized deviation is greater than 1 in multiple tests, determining that the validity period of the standard substance to be evaluated does not match the nominal validity period, and determining that the standard substance to be evaluated does not meet the quality requirements of environmental quality evaluation.

[0040] The embodiment scheme of the present disclosure determines the first judgment index for evaluating the concentration value of the standard substance to be evaluated according to the environmental monitoring analysis method, and uses the aforementioned first judgment index and the measured concentration value and nominal concentration value of the standard substance to be evaluated to determine whether the standard substance to be evaluated meets the quality requirements of environmental monitoring evaluation. That is, the embodiment scheme of the present disclosure evaluates the standard substance to be evaluated from the application perspective, and its evaluation is more targeted, and the evaluation results are directly usable. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0042] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure or the prior art, the following briefly introduces the drawings required for use in the embodiments or the prior art description. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor, including

[0043] Figure 1 It is a flow chart of the evaluation method of standard substances in the field of environmental monitoring provided by the embodiment of the present disclosure. DETAILED DESCRIPTION

[0044] Embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although certain embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be construed as being limited to the embodiments described herein, which are instead provided to provide a more thorough and complete understanding of the present disclosure. It should be understood that the drawings and embodiments of the present disclosure are only for exemplary purposes and are not intended to limit the scope of protection of the present disclosure.

[0045] The term "including" and its variations used in this document are open inclusions, i.e., "including but not limited to". The term "based on" means "based at least in part on". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one other embodiment"; the term "some embodiments" means "at least some embodiments". Relevant definitions of other terms will be given in the following description. In this document, relational terms such as "first" and "second" are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply these entities or operations.

[0046] The disclosed embodiment provides a method for evaluating standard substances in the field of environmental monitoring. Figure 1 : is a flow chart of the evaluation method of standard substances in the field of environmental monitoring provided by the embodiment of the present disclosure. Figure 1 As shown, the evaluation method provided by the embodiment of the present disclosure includes S110-S140.

[0047] S110: Testing the standard substance to be evaluated to determine the actual measured concentration value of the target component in the standard substance to be evaluated.

[0048] In specific implementation, a qualified testing laboratory that has passed standard certification (for example, CMA or CNAS certification) and annual inspection can be used to test the standard substance to be evaluated according to a predetermined standard test method to determine the measured concentration value of the target component in the standard substance to be evaluated. The aforementioned measured concentration value is the measured concentration value obtained by averaging multiple measurements. It should be noted that when the testing laboratory tests the standard substance to be evaluated, its testing experiment process should strictly follow the operating specifications to avoid introducing systematic errors and causing errors in the experimental results.

[0049] S120: Obtain the nominal concentration value of the target component in the standard substance to be evaluated.

[0050] In a specific implementation, the nominal concentration value of the target component can be found in the product quality report provided by the manufacturer of the standard substance to be evaluated.

[0051] S130: Calculate the concentration error between the measured concentration value and the nominal concentration value, and determine whether the concentration error is greater than a predetermined first determination index.

[0052] S140: Determine whether the standard substance to be evaluated does not meet the quality requirements of environmental monitoring and evaluation.

[0053] In practical applications, not all standard substances to be evaluated can meet the requirements of environmental monitoring and analysis methods. Therefore, it is necessary to determine the judgment indicators based on the environmental monitoring and analysis methods, and evaluate and screen the standard substances to be evaluated to remove standard substances that do not meet the quality requirements of environmental monitoring and evaluation.

[0054] The first determination index is an index determined based on the environmental monitoring and analysis method. Specifically, the first determination index is an index determined based on the spike recovery rate, the concentration error of the quality control sample measurement result, and the maximum allowable error requirement of the standard concentration point in the environmental monitoring and analysis method.

[0055] In a specific implementation, the first determination index may be an absolute index or a relative index, which is not particularly limited in the embodiments of the present disclosure. Preferably, the first determination index is a relative index.

[0056] In the case where the first determination index is a relative index, the concentration error determined according to the measured concentration value and the nominal concentration value should also be a relative error. or Determine the concentration error. Where C d is the measured concentration of the target component in the standard substance to be evaluated, C s is the nominal concentration value of the target component in the standard substance to be evaluated.

[0057] After determining the concentration error, the concentration error can then be compared with the first judgment index to determine whether the concentration error is greater than the predetermined first judgment index. If the concentration error R is less than or equal to the first judgment index, it is determined that the nominal concentration value and the measured concentration value of the standard substance to be evaluated are within reasonable expectations, and the subsequent values ​​obtained by equipment calibration and data measurement based on the standard substance to be evaluated are relatively accurate; on the contrary, if the concentration error R is greater than the first judgment index, it is determined that the nominal concentration value and the measured concentration value of the standard substance to be evaluated are not within reasonable expectations, and the subsequent values ​​obtained by equipment calibration and data measurement based on the standard substance to be evaluated cannot determine the reliability, based on which it is determined that the standard substance to be evaluated does not meet the quality requirements of environmental monitoring and evaluation.

[0058] It should be noted that the aforementioned evaluation method is only used to determine the applicability of the standard substance to be evaluated to the environmental monitoring analysis method. In practical applications, in addition to the aforementioned applicability indicators, there are other indicator requirements. Accordingly, other determination methods are also needed to determine other quality requirements of the standard substance to be evaluated.

[0059] The embodiment of the present disclosure determines the first determination index for evaluating the concentration value of the standard substance to be evaluated according to the environmental monitoring analysis method, and uses the aforementioned first determination index and the measured concentration value and nominal concentration value of the standard substance to be evaluated to determine whether the standard substance to be evaluated meets the quality requirements of environmental monitoring evaluation. That is, the embodiment of the present disclosure evaluates the standard substance to be evaluated from the perspective of application, and its evaluation is more targeted, and the evaluation results are directly usable.

[0060] In a specific implementation, the environmental monitoring analysis method includes a sample spike test. Correspondingly, it is also necessary to evaluate whether the standard sample to be evaluated meets the environmental monitoring analysis requirements due to the sample spike operation. In order to achieve the aforementioned evaluation (here the evaluation can be called the pre-processing operation impact evaluation), the following S150-S160 can also be performed.

[0061] S150: Use higher-grade substances to perform spike testing on the standard substances to be evaluated, and obtain the corresponding spike recovery rate.

[0062] Higher-level standard substances are substances that have the same target components as the standard substances to be evaluated, and have higher requirements as standard substances (in most cases, higher-level standard substances are substances in which the concentration value and standard uncertainty of the target components are determined by absolute measurement or multiple measurement methods). In specific implementations, the standard substances to be evaluated are mostly secondary standard substances, while higher-level standard substances are primary standard substances.

[0063] In specific implementation, operators can use a reasonable spike test method, adopt higher-level standard substances as sample substances (in this case, it is assumed that the standard substances to be evaluated are reference standard substances for actual application) to configure and test experimental samples, and use corresponding calculation methods to obtain corresponding spike recovery rates.

[0064] S160: Determine whether the spiked recovery rate meets the recovery rate standard range in the environmental monitoring analysis method; if not, execute S140.

[0065] In specific implementation, the recovery rate standard range in the environmental monitoring analysis method needs to be determined according to the specific monitoring field, so the embodiment of the present disclosure does not specifically limit it. The above recovery rate standard range is a relative range.

[0066] In actual applications, manufacturers may set the components of the standard substances to be evaluated according to the mainstream market demand during the manufacturing process of the standard substances to be evaluated. When used in the field of environmental monitoring, in addition to the target components playing a role in calibration and test operations, other substances therein may also interfere with the experimental process. Therefore, it is necessary to consider the degree of influence of the aforementioned interfering components on environmental monitoring analysis, and then consider whether the standard substances to be evaluated are available. In specific implementations, the computing device can use the following S170-S190 to determine whether the standard substances to be evaluated are available.

[0067] S170: Determine whether the standard substance to be evaluated has interfering components based on the product quality report of the standard substance to be evaluated.

[0068] Interfering components are components that have an impact on environmental monitoring and evaluation in addition to the target components. In the product quality report of the standard substance to be evaluated, there is generally data on the cost of its components. Based on the component data, it can be determined whether there are interfering components in the standard substance to be evaluated. It should be noted that the determination of interfering components needs to be determined based on the method steps of the environmental monitoring analysis method and the characteristics of the test instrument used.

[0069] S180: In the case where the standard substance to be evaluated has an interfering component, a quantitative measurement method for the interfering component is determined based on the material properties of the target component and the interfering component, and the actual measured concentration data of the interfering component is determined using the quantitative measurement method.

[0070] In the case where it is determined that there are interfering components in the standard substance to be evaluated, in order to achieve quantitative measurement of the interfering components, it is necessary to select a reasonable quantitative measurement method based on the material properties of the interfering components and the material properties of other components (such as the target component) in the standard substance to be evaluated. After selecting the quantitative measurement method for the interfering components, the aforementioned quantitative measurement method can then be implemented to determine the actual measured concentration data of the interfering components.

[0071] In a specific implementation, the measured concentration data of the interfering component may include data such as the measured concentration value of the interfering component and the standard uncertainty of the interfering component.

[0072] S200: Determine whether the standard substance to be evaluated meets the quality requirements of environmental monitoring evaluation based on the measured concentration data of the interfering component; if not, execute S140.

[0073] After determining the measured concentration data of the interfering component, a comparative analysis can be performed based on the limit concentration determined in advance in the environmental monitoring and analysis method to determine whether the content of the interfering component exceeds the standard. If the interfering component is still below the limit concentration of the environmental monitoring and analysis method, it is determined that the standard substance to be evaluated is unusable.

[0074] In practical applications, the standard substance to be evaluated may be a standard substance with volatile components or solvents. The volatilization of the volatile components will affect the concentration of the target component, thereby affecting the accuracy of subsequent calibration and reference tests. In addition, the standard substances to be evaluated are generally produced in batches, and the different contents of volatile components in different matches will also affect the concentration of the target component. In order to ensure the reliability of the subsequent use process and the comparability of data in the subsequent environmental monitoring process, it is necessary to evaluate the uniformity of the standard substance to be evaluated. In the specific implementation, the computing device can use the following S210-S230 to evaluate the uniformity of the standard substance to be evaluated.

[0075] S210: Testing different batches of the standard substances to be evaluated respectively to determine the actual measured concentration value of the target component in each batch of the standard substances to be evaluated.

[0076] S220: Determine whether the measured concentration value of the target component in the standard substance to be evaluated meets the consistency evaluation index; if not, execute S140.

[0077] In a specific implementation, after obtaining the measured concentration value of the target component in the standard substance to be evaluated, various consistency test methods commonly used in the existing statistical field can be used to evaluate the measured concentration values ​​of each standard substance to be evaluated to determine whether the measured concentration values ​​meet the corresponding consistency evaluation standards.

[0078] In some embodiments, in addition to using various data provided by the product quality report, in order to obtain more authoritative data, the certification scope, validity period and other information of various types of standard materials and standard samples to be evaluated can also be obtained from sources such as the National Standard Material Resource Sharing Voucher and the National Standard Information Public Service Platform to ensure the authenticity and accuracy of the data.

[0079] The aforementioned test method is mainly to test the applicability of the standard substance to be evaluated to the environmental monitoring and evaluation method. In addition to considering the applicability to the environmental monitoring and evaluation method, it is also necessary to consider the reliability of the quality of the standard substance to be evaluated. The aforementioned reliability is reflected in the accuracy of the target component concentration value and the standard uncertainty. And the evaluation of the reliability of the quality of the standard substance to be evaluated is the prerequisite for the aforementioned compliance evaluation.

[0080] To solve this problem, in some embodiments of the present disclosure, when testing the standard substance to be evaluated, the measured standard uncertainty of the standard substance to be evaluated can also be determined. The measured standard uncertainty can be determined by various errors introduced during the test. In addition, during the test process, it is also necessary to test a higher-level standard substance to determine the measured concentration value and measured standard uncertainty of the target component in the higher-level standard substance.

[0081] On the premise of executing the aforementioned determination of the measured concentration value and the measured standard uncertainty of the standard substance to be evaluated, before executing the aforementioned S130, the following 230-S240 may also be executed.

[0082] S230: Calculate the normalized deviation based on the measured concentration value and the measured standard uncertainty of the standard substance to be evaluated, and the measured concentration value and the measured standard uncertainty of a higher-level standard substance.

[0083] In specific implementation, it can be used Calculate the normalized deviation. Where x L is the measured concentration value of the target component in the standard substance to be evaluated, u(x L ) is the measured standard uncertainty of the target component in the standard substance to be evaluated, x Ris the measured concentration value of the target component in the higher-level standard material, u(x R ) is the standard uncertainty of the target component in the higher-level reference material.

[0084] S240: When the absolute value of the normalized deviation is greater than 1, it is determined that the standard substance to be evaluated does not meet the quality requirements of the environmental monitoring evaluation.

[0085] According to the principle of mathematical statistics, if the absolute value of the normalized deviation is greater than 1, it is determined that the difference between the standard sample to be evaluated and the corresponding higher-level standard material exceeds reasonable expectations and is no longer credible. At this time, it is determined that the evaluation standard material does not meet the quality requirements of environmental monitoring and evaluation. On the contrary, if the absolute value of the normalized deviation is less than 1, it is determined that the difference between the standard material to be evaluated and the corresponding higher-level standard material is within reasonable expectations, and its practical application is credible.

[0086] In some embodiments, in order to ensure test reliability and avoid errors caused by inaccurate test results in a single laboratory, in specific implementations, the standard substance to be evaluated and the higher-level standard substance can be tested in at least two testing laboratories to determine the measured concentration value and the measured standard uncertainty of the corresponding target component, and the corresponding normalized deviations can be calculated respectively.

[0087] When executing the previous steps, at least two normalized deviations will be obtained. In this case, it is also necessary to comprehensively process each normalized deviation to obtain an indicator for judging whether the standard substance to be evaluated meets the quality requirements of environmental monitoring and evaluation. In specific implementation, the average value of the absolute values ​​of each normalized deviation can be calculated, and the average value can be used as the basis for judging whether the labeled substance to be evaluated meets the quality requirements of environmental monitoring and evaluation. According to the ideas in the previous article, if the average value is greater than 1, it is determined that the standard substance to be evaluated does not meet the quality requirements of environmental monitoring and evaluation.

[0088] In practical applications, before using at least two experiments to process the standard samples to be evaluated, it is necessary to determine the equivalence of the test results of each testing laboratory. To this end, before performing the aforementioned test work, specifically before performing the aforementioned S230-S240, the following S250-S260 may also be performed.

[0089] S250: Two testing laboratories test higher-level reference materials to determine the measured concentration values ​​of the target components and the corresponding expanded uncertainties.

[0090] In specific implementation, at least two testing laboratories should test higher-level standard materials according to the same experimental testing procedures to determine the actual measured concentration values ​​of the target components and the corresponding expanded uncertainties.

[0091] S260: Based on Determine whether the test methods of the two laboratories are equivalent; if equivalent, execute S230-S240.

[0092] In the S260 formula, is the measured concentration value of the first laboratory, is the measured concentration value of the second laboratory, is the expanded uncertainty of the concentration value measured in the first laboratory, is the expanded uncertainty of the concentration value measured by the first laboratory; S(x) is the standard deviation of N experimental tests, where N is the number of tests of higher-grade reference materials performed by a laboratory.

[0093] In a specific implementation, if the above formula is established, it is determined that the experimental data of two laboratories are equivalent to each other, and the operating steps of the above method can be executed.

[0094] It should be noted that before performing the aforementioned tests, it is necessary to consider various imaging factors in the experimental quality control process and implement experimental quality control in accordance with laboratory operating procedures and standard analysis methods. In specific implementation, before performing the aforementioned operations, the following operations need to be performed: (1) Before conducting sample tests, first perform a blank test on the system to ensure that the target component will not be detected by the test instrument; (2) The standard substance to be tested needs to be placed in the standard environment of the test laboratory (e.g., room temperature 20°C) for more than 24 hours before testing; (3) When the standard substance to be tested is a gas, before connecting the gas cylinder to the pressure reducing valve and the connecting pipeline, first use a high-purity inert gas (e.g., high-purity nitrogen) to purge the pressure reducing valve and the pipeline for a first set time, and then purge the gas cylinder, the pressure reducing valve, and the connecting pipeline with the gas to be tested for a second set time to eliminate the influence of residual gas, so as to ensure that the instrument response is stable before testing.

[0095] In the specific implementation, it is also necessary to conduct a stability evaluation on the standard substance to be evaluated. Stability evaluation is an evaluation used to evaluate whether the performance of the standard substance to be evaluated is stable during its validity period. In the specific implementation, the aforementioned test can be performed at least twice within the calibrated validity period of the standard substance to be evaluated, and the normalized deviation of each test can be calculated respectively. Correspondingly, when at least one of the normalized deviations in each test has an absolute value greater than 1, it is determined that the validity period of the standard substance to be evaluated does not match the nominal validity period, and thus it is determined that the standard substance to be evaluated does not meet the quality requirements of the environmental quality evaluation. In practical applications, try to conduct a test before the standard substance to be evaluated is about to expire before the nominal validity period to ensure the comprehensiveness of the evaluation.

[0096] In the specific implementation, in order to ensure the confidentiality of the brand and model of the standard substance to be evaluated and avoid fraud, the standard substance to be evaluated can be purchased anonymously by a third-party laboratory. The purchased standard substance to be evaluated is transcoded, and the transcoding should be specially processed according to the characteristics of the standard substance to be evaluated, the purpose of the evaluation, etc. The transcoding is to hide or add part of the original coded information. It is necessary to hide information that affects the measurement results, such as sample concentration and sample number. It is necessary to add the necessary information required for the evaluation process, such as the transcoded coded information, the items to be measured, and the method selected for the measurement. Ensure that the testing laboratory can obtain the necessary analysis and detection information through the transcoded number, but cannot obtain other information of the standard substance that affects the measurement results.

[0097] The transcoding can be in the form of a QR code or a digital random code. The relevant information of the standard substance to be evaluated is embedded in the QR code, and the transcoded information can be obtained by scanning the QR code. The digital random code should be followed by the necessary information of the transcoded standard substance. After transcoding, the concentration of the sample to be tested, the manufacturer information and other information of the gas-type standard substance to be evaluated are hidden, and the test method, test points, test items, storage conditions and other information are added. If it is a multi-component standard substance to be evaluated, each component to be tested and the test points should be listed. After transcoding, the solvent composition of the water quality standard substance to be evaluated should be indicated. If it contains interfering components, it should be distinguished whether the interfering components affect the measurement results, identify the interference type such as positive interference or negative interference, and conduct an interfering component inspection when necessary. At the same time, the dilution situation, pretreatment and other contents should be indicated. According to the situation, indicate the information of each sample bottle of the standard substance to be evaluated. If there are differences between the sample bottles, the uniformity of the sample should be evaluated. The transcoded information of the solid standard substance to be evaluated usually includes information such as the type of solid sample, the number of samples, the analysis items, the analysis method, and the reporting unit. The transcoded number should correspond to the original code one by one, and the basic information of the standard substance should be associated, such as the standard substance number, concentration, manufacturer, volume, storage conditions, dilution or pretreatment conditions, etc., so that after the measurement is completed, the measurement results can be statistically analyzed and evaluated.

[0098] Before performing the aforementioned experimental tests, a detection and measurement method with good accuracy, high precision and small uncertainty should be selected. Under the premise of ensuring accuracy and precision, in principle, methods based on commonly used measurement principles in the field of environmental monitoring should be given priority.

[0099] Subsequently, the key performance indicators of the relevant measurement methods (such as measurement range, linear range, detection limit, quantitative limit, accuracy, precision, measurement uncertainty, etc.) are analyzed and optimized and verified to confirm that they meet the evaluation requirements. If the method for determining the value of the standard substance / standard sample of a project is different from the selected environmental monitoring standard method, and there are differences in the measurement results, the measurement method should be further studied and optimized to identify the source of the difference and eliminate it. If it cannot be eliminated, the commonly used analysis method of the monitoring system can be used as the test method for evaluating the suitability of the monitoring work.

[0100] In specific implementation, in order to avoid introducing errors, try not to perform operations such as container conversion and dilution on the standard substance / standard sample during measurement. For the measurement of target components in standard substances / standard samples, a complete measurement method usually also includes: pretreatment and injection methods, analytical instrument conditions, calibration methods, number of repeated measurements, data processing and uncertainty evaluation, etc.

[0101] For gas reference materials / standard samples, the gas injection method in the measurement method should be strictly controlled in order to obtain accurate measurement results. Especially when there are significant differences in the gas storage method or pressure state between the measured samples or reference standards, the appropriate injection method should be selected to ensure that different gases have the same injection state (such as pressure, temperature, flow, etc.).

[0102] For liquid standard substances / standard samples, when enrichment methods are used in pretreatment or dilution is necessary, the impact on the accuracy and uncertainty of the measurement results should be fully evaluated. When diluting, the impact of solvents, standard solution volatilization, etc. on the uncertainty of the measurement results should be comprehensively considered, and the appropriate dilution procedure and volume determination method should be selected. The dilution procedure of high-concentration liquid standard substances (need to be diluted) should be carefully designed to control the uncertainty of the measurement results as small as possible.

[0103] When calibrating the measurement results of analytical instruments, liquid standard materials with higher levels in the calibration level sequence should be used as reference standards. For example, if the standard material is not a national certified standard material / standard sample, the reference standard can be a national second-level certified standard material, a national first-level certified standard material, a national environmental certified standard sample, or a standard material / standard sample that has been mutually recognized through international metrology comparisons; if the standard material is a national second-level certified standard material, the reference standard can be a national first-level certified standard material, a national environmental certified standard sample, or a standard material / standard sample that has been mutually recognized through international metrology comparisons. When there is a lack of national certified standard materials / standard samples as reference standards, brands with a relatively high usage rate can be selected as reference standards, but at this time, only the consistency of the reference standard and the sample being measured can be compared, and no accuracy judgment can be made. Usually, calibration methods can be used, but not limited to, single-point calibration, multi-point calibration, etc. Generally speaking, increasing the calibration frequency and reducing the concentration difference between the reference standard and the sample being measured can usually obtain more accurate measurement results. Single-point calibration is more suitable for situations where the target component concentration in the reference standard should be close to the target component concentration in the sample to be tested, and the concentration level of the sample to be tested is the same or similar. This is common in gas standard substance / standard sample comparisons. When the concentration levels of the target components in the sample to be tested vary greatly, multi-point calibration can be used. Since the concentration of the sample to be tested is known, a calibration curve can be established based on the actual concentration level range of the sample to be tested; the sample to be tested can also be diluted to a concentration close to that of the target component in the reference standard, and a single-point calibration method can be used. The calibration method can be determined by comprehensively considering factors such as the uncertainty assessment results of the measurement results and the measurement range of the measurement method.

[0104] According to the above ideas, during the implementation of this plan, according to the survey results of the use of NH3, NO, and SO2 standard gases commonly used in environmental monitoring, 58 bottles of standard gases corresponding to various brands were purchased (including 24 bottles of NO standard gas, 14 bottles of NH3 standard gas, and 20 bottles of SO2 standard gas). After testing, 20 bottles of the 24 bottles of NO standard gas had a normalized deviation absolute value ≤ 1, and the qualified rate was 83%; 12 bottles of the 14 bottles of NH3 standard gas had a normalized deviation absolute value ≤ 1, and the qualified rate was 86%; 18 bottles of the 20 bottles of SO2 standard gas had a normalized deviation absolute value ≤ 1, and the qualified rate was 90%.

[0105] The above are only specific embodiments of the present disclosure, so that those skilled in the art can understand or implement the present disclosure. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present disclosure. Therefore, the present disclosure will not be limited to these embodiments herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for evaluating standard substances in the field of environmental monitoring, characterized in that: include: Test the standard substance to be evaluated to determine the actual measured concentration value of the target component in the standard substance to be evaluated; And, obtaining the nominal concentration value of the target component in the standard substance to be evaluated; Calculating the concentration error between the measured concentration value and the nominal concentration value, and judging whether the concentration error is greater than a predetermined first determination index, wherein the first determination index is determined according to the spiked recovery error, the concentration error of the quality control sample measurement result, and the maximum allowable error of the standard concentration point in the environmental monitoring analysis method; When the concentration error is greater than the determination index, it is determined that the standard substance to be evaluated does not meet the quality requirements of environmental monitoring evaluation.

2. The method according to claim 1, characterized in that: The calculating the concentration error between the measured concentration value and the nominal concentration value comprises: C d -C s Using C s Determine the concentration error, where C d is the measured concentration of the target component in the standard substance to be evaluated, C s is the nominal concentration value of the target component in the standard substance to be evaluated.

3. The method according to claim 1, characterized in that: The environmental monitoring analysis method includes sample spike testing; The method further comprises: The method further comprises: using a higher-grade substance to perform a spike test on the standard substance to be evaluated to obtain a corresponding spike recovery rate; Determine whether the spiked recovery rate meets the recovery rate standard range in the environmental monitoring analysis method; When the spiked recovery rate does not meet the recovery rate standard range, it is determined that the standard substance to be evaluated does not meet the quality requirements of environmental monitoring evaluation.

4. The method according to claim 1, characterized in that: The method further comprises: Determine whether the standard substance to be evaluated has an interfering component based on the product quality report of the standard substance to be evaluated, wherein the interfering component is a component other than the target component that has an impact on environmental monitoring and evaluation; In the case where the standard substance to be evaluated has an interfering component, determining a quantitative measurement method for the interfering component based on the material properties of the target component and the interfering component; Determining the measured concentration data of the interfering component by using the quantitative measurement method; Based on the measured concentration data of the interfering component, determine whether the standard substance to be evaluated meets the quality requirements of environmental monitoring evaluation.

5. The method according to claim 1, characterized in that The standard substance to be evaluated is a standard substance having a volatile component; the method further comprises: Test different batches of the standard substances to be evaluated separately to determine the actual measured concentration values ​​of the target components in each batch of the standard substances to be evaluated; Determine whether the measured concentration value of the target component in the standard substance to be evaluated meets the consistency evaluation index; When the measured concentration value of the target component in the standard substance to be evaluated does not meet the consistency evaluation index, it is determined that the standard substance to be evaluated does not meet the quality requirements of environmental monitoring evaluation.

6. The method according to any one of claims 1 to 5, characterized in that: When testing the standard substance to be evaluated, determine the measured standard uncertainty of the target component in the standard substance to be evaluated; The method further comprises: testing a higher-level standard substance to determine a measured concentration value and a measured standard uncertainty of a target component in the higher-level substance; Before calculating the concentration error between the measured concentration value and the nominal concentration value, the method further includes: Calculate the normalized deviation based on the measured concentration value and the measured standard uncertainty of the standard substance to be evaluated, as well as the measured concentration value and the measured standard uncertainty of a higher-level standard substance; When the absolute value of the normalized deviation is greater than 1, it is determined that the standard substance to be evaluated does not meet the quality requirements of environmental monitoring evaluation.

7. The method according to claim 6, characterized in that Testing the standard substance to be evaluated and the higher-level standard substance in at least two testing laboratories to determine the measured concentration value and measured standard uncertainty of the corresponding target component, and calculating the corresponding normalized deviation; The method further comprises: obtaining an average of the absolute values ​​of the normalized deviations; When the absolute value of the normalized deviation is greater than 1, determining that the standard substance to be evaluated does not meet the quality requirements of environmental monitoring evaluation includes: when the average value is greater than 1, determining that the standard substance to be evaluated does not meet the quality requirements of environmental monitoring evaluation.

8. The method according to claim 7, characterized in that Before at least two testing laboratories test the standard substance to be evaluated and the higher-level standard substance, the method further comprises: The higher-level reference materials are tested by two testing laboratories to determine the measured concentration values ​​of the target components and the corresponding expanded uncertainties; based on Whether it is established to determine whether the test methods of two laboratories are equivalent, is the measured concentration value of the first laboratory, is the measured concentration value of the second laboratory, is the expanded uncertainty of the concentration value measured in the first laboratory, is the expanded uncertainty of the concentration value measured by the first laboratory; In the case where the testing methods of two laboratories are equivalent, the step of testing the standard substance to be evaluated and the higher-level standard substance in at least two testing laboratories is performed.

9. The method according to claim 8, characterized in that The standard substance to be evaluated and the higher-level standard substance are both gaseous substances; Before at least two testing laboratories test the reference material to be evaluated and the higher-level reference material, The test instrument is purged with high-purity inert gas for at least a first set time, and then the test instrument is purged with the to-be-tested standard substance or the higher-grade standard substance for at least a second set time.

10. The method according to claim 7, characterized in that Performing at least two tests and calculating normalized deviations within the calibration validity period of the standard substance to be evaluated; The method of determining that the standard substance to be evaluated does not meet the quality requirements of environmental monitoring evaluation when the absolute value of the normalized deviation is greater than 1 includes: when at least one absolute value of the normalized deviation is greater than 1 in multiple tests, determining that the validity period of the standard substance to be evaluated does not match the nominal validity period, and determining that the standard substance to be evaluated does not meet the quality requirements of environmental quality evaluation.

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