HJ/T 168-2004Technical Guidelines for the Establishment of Environmental Monitoring Analysis Method Standards (English PDF)

5.1 General requirements

The main technical content of the standard formulation of environmental monitoring analysis methods includes standard formulation demand analysis, domestic and foreign related standards Standard and literature research, method condition test research, method characteristic index confirmation in laboratory, method comparison, method verification, and Standard text and compilation instructions are compiled, and the technical route is shown in Figure 1.

5 Route, application situation, etc., and the content to be used for reference.

5.3.2 Investigate the relevant method standards of other countries and international organizations, and clarify the scope of application of relevant foreign method standards, Determine the target, technical route, application situation, etc., and the content to be used for reference.

5.3.3 Collect literature on relevant analysis methods, study the conditional factors of method establishment, and clarify the content to be used for reference.

5.3.4 Clarify the method standard target and the analysis method to be adopted, and clarify the conditions that need to be studied and analyzed in the process of method establishment Factors, put forward the test plan and main work content, and form the technical route of method establishment.

5.4 Method condition test study

5.4.1 Experimental research on sample collection and storage conditions

a) On the basis of relevant environmental monitoring technical specifications, research and propose methods for special requirements for sample collection, including Including sampling methods, sampling equipment, reagent materials, etc., carry out sampling efficiency or penetration test research when necessary;

b) Research and propose methods for the requirements of sample storage utensils, preservatives, storage time and temperature;

c) Research and put forward requirements for the preparation and storage time of standard solutions and other related reagents and materials;

d) When necessary, study and put forward requirements for sample pretreatment at the sampling site.

5.4.2 Experimental research on sample pretreatment conditions

a) Research and propose methods for sample digestion, extraction, enrichment, purification and other pretreatment conditions;

b) Carry out necessary penetration tests, propose adsorption and enrichment capacities under certain conditions, and appropriate injection volume and determination Concentration range

c) Study the applicability of using this method for determination of high-concentration (content) samples after dilution, and propose the dilution operation Claim.

5.4.3 Interference test research

a) Analyze the interference (signal, peak, etc.) to the target;

b) When the conditions are met, the interfering substances and the amount of interference should be specified;

c) Combining literature and experiments, research and propose methods to eliminate interference.

5.4.4 Experimental research on analysis and test conditions

a) Research and propose methods and requirements for sample preparation;

b) Research and put forward requirements for instrument debugging and calibration parameters;

c) If a calibration curve needs to be established, the best linear range should be determined according to the experiment, and the relevant ecological Convergence of limit concentration (content) levels in standards, ecological environment risk control standards, and pollutant discharge standards;

Generally, at least 6 calibration points (including zero concentration) are required to be distributed as evenly as possible in the linear range, quantitative Method The correlation coefficient of the linear regression equation is not less than 0.999;

d) If the average relative response factor is used for calculation, it is generally required that the relative standard deviation of the relative response factor does not exceed 20%;

e) Research and propose the operation steps and condition parameters of the determination.

If the target is not detected in 7 products, the sample can be obtained by adding standard to the actual sample matrix.

5.6.5 Collect at least 7 samples with similar concentration levels for each type of actual sample, and adopt the new method and the standard of the comparison method respectively Perform measurement and obtain at least 7 sets of paired measurement data. When sufficient actual sample quantity cannot be obtained, actual sample can be used at least 7 sets of paired measurement data are obtained by the method of matrix addition. The paired sample t test method can be used to determine the two methods of determination Whether the results are significantly different, see Appendix B for specific methods; other applicable statistical test methods can also be used according to specific conditions law.

5.7 Method verification

Method verification is performed in accordance with the requirements of Chapter 6.

5.8 Standard text and compilation instructions

5.8.1 The structural elements of the standard text shall be implemented in accordance with the requirements of Chapter 7.

5.8.2 The standard text is compiled in accordance with the requirements of Chapter 8.

5.8.3 The standard opening report and preparation instructions shall be prepared in accordance with the requirements of Appendix C and Appendix D.

5.9 Calculation rules for approximate results during research

5.9.1 When adding and subtracting approximate values, the number of significant digits of the sum or difference obtained shall be the same as the number of digits after the decimal point in each approximate value.

with. In the process of calculation, one more decimal place can be kept, and the numerical value of the calculation result is rounded according to the requirements of GB/T 8170.

5.9.2 When the approximate value is multiplied and divided, the resultant product and the number of significant digits of the quotient shall be the same as the number of significant digits of each approximate value.

with. In the process of calculation, you can first round each approximate value to one more than the one with the least significant number of digits, and finally calculate the result.

The results are processed according to the above rules.

5.9.3 When the approximate value is squared or rooted, the number of significant digits of the calculation result is the same as that of the original approximate value.

5.9.4 In the logarithmic calculation of the approximate value, the number of digits after the decimal point of the result (excluding the leading digit) should be the same as the significant digits of the original number the numbers are the same.

5.9.5 When calculating the average of four or more values with close accuracy, the effective digits can be increased by one.

5.9.6 If the quantitative value of a certain type of substance is obtained by adding the measurement results of multiple components (such as total xylene, organochlorine the total amount of medicine, etc.), the contract should be calculated before revision, and no second revision should be made.

6.1 General requirements

6.1.1 The purpose of method verification is to further confirm the scientificity of the method, and to examine the applicability and feasibility of the method under various environmental conditions.

Operate, and finally determine the characteristic index and quality assurance and quality control requirements of the method according to the data of each verification laboratory.

6.1.2 The characteristic indexes of each type of method verification are the same as those confirmed in the laboratory. See Table 1 for details.

6.1.3 The draft method standard shall be verified by at least 6 laboratories. The laboratories participating in the method verification should pass the inspection and testing machine Qualification accreditation or laboratory accreditation, with verification experiment conditions; should cover a representative geographical area (or typical environmental Files), and can cover all levels of national environmental monitoring agencies. If the 6 verification laboratories cannot be obtained, the same A laboratory is divided into groups of different personnel, and uses different equipment, environmental conditions and different batches of reagent materials as much as possible.

Exhibition verification.

86.1.4 The standard preparation team shall prepare a method verification plan, based on the main factors affecting the accuracy (precision, correctness) of the method Factors and mathematical statistics require selection of appropriate sample types, instruments and equipment, analysis time, etc. Verification instruments and equipment should Cover the main types of the market, including domestic instruments and equipment as much as possible.

6.1.5 Use certified reference materials/standard samples (or samples prepared with commercially available reagents and standard samples) and actual samples for method verification, actual samples should try to cover the applicable scope of the method standard. The verification samples should be compiled as standard as possible 1.The samples distributed to the verification laboratories, or the samples with the same matrix (abbreviated as as a "uniform sample"). In principle, the verification sample should be a highly uniform sample. When the sample cannot be homogenized (such as metal, rubber Solid waste samples such as glue or textiles), the verification data should indicate the type of sample that is only applicable to the test.

6.1.6 The reagents and materials, instruments and equipment and analysis procedures used in the method verification process should meet the relevant requirements of the method.

6.1.7 Before the method verification, the operators participating in the verification should be familiar with and master the method principle, operation steps and process.

Should receive training when.

6.1.8 The operators participating in the verification and the standard preparation group should truthfully fill in the "Method Verification Report" as required (see appendix E) "Original Test Data Sheet", and attach a map or other equipment produced by the instrument that matches the content of the original test data sheet.

Health record printouts, etc.

6.1.9 Refer to the relevant content in GB/T 6379 for the elimination method of abnormal values during the verification process.

Explain, correct, or eliminate fully explain.

6.1.10 The standard preparation team will finally form the "Method Validation Report" based on the method verification data and statistics, analysis and evaluation results.

6.2 Specific requirements

6.2.1 Verification of the detection limit

If the method in Appendix A.1.1 is used to determine the detection limit, each verification laboratory shall use a uniform sample and follow the method operation steps and flow.

Process analysis operations, calculate the average value, standard deviation, relative standard deviation, detection limit and other parameters of the results.

The method detection limit determined by each verification laboratory is. the detection limit value calculated according to the method in Appendix A.1.1, and the instrument the detection limit is compared and the larger value is used.

The final method detection limit is. the highest value of the method detection limit determined by each verification laboratory.

6.2.2 Verification of precision

Determination of certified reference materials/standard samples (or samples prepared with commercially available reagents and standard samples). each verification laboratory Use high (concentration or content near 90% of the upper limit of the linear range of the calibration curve), medium (concentration or content near the middle point of the calibration curve) Content), low (concentration or content near the lower limit of determination) 3 uniform samples with different concentrations or the samples are measured in parallel for at least 6 times, and the average value, standard deviation, and relative standard deviation of each concentration or content sample determination are calculated respectively.

Difference and other parameters.

Measurement of actual samples. Each verification laboratory shall deal with 1 to 3 concentrations or contents of each sample type within the applicable scope (should Contain as much as possible the concentration of applicable ecological environmental quality standards, ecological environmental risk control standards, and pollutant discharge standard limits or content) of the sample, each sample is tested in parallel for at least 6 times in the whole procedure, and the concentration or content of each type of sample is calculated separately.

The average value, standard deviation, relative standard deviation and other parameters of the measurement sample. If it is not possible to obtain the appropriate concentration or content for international samples, the actual sample matrix can be used for verification (when the sample is detected, the concentration of the standard addition should be 0.5~ 3 times; when the sample is not detected, the spiked concentration should include the applicable ecological environmental quality standards and ecological environmental risk control as much as possible

8.4 Standard name

8.4.1 The standard name adopts a three-stage expression, namely. the environmental monitoring elements to which the method standard applies, and the target analyzed the name of the substance and analysis method.

8.4.2 The English name of the standard should be written.

Example 1.Determination of dissolved oxygen in water quality by electrochemical probe method Water quality-Determination of dissolved oxygen-Electrochemical probe method

Example 2.Determination of Volatile Halogenated Hydrocarbons in Soils and Sediments Purge and Trap/Gas Chromatography-Mass Spectrometry Soil and sediment-Determination of volatile halohydrocarbons-Purge and trap gas chromatography mass spectrometry method

8.5 Warning

When using this standard, the reagents and materials that are highly toxic, flammable, explosive, corrosive, radioactive, and highly volatile should be given.

Materials, as well as safety and protection items that require special attention.

8.6 Scope of application

8.6.1 The environmental monitoring elements, targets and analysis methods applicable to the standard shall be explained.

8.6.2 The detection limit, lower limit of determination and upper limit of determination (if necessary) or measurement range of the target should be stated. If needed, give the detection limit and the lower limit of determination corresponding to different sampling situations, different sample sizes, and different test conditions are shown. For multiple goals the standard of the substance, the detection limit of its method, the lower limit of determination, etc. can be listed in the standard as a "normative appendix".

8.6.3 If several analytical methods are included in the standard, the applicable scope of each analytical method should be clearly indicated.

8.6.4 The content that is not included in the standard name but needs to be explained.

8.6.5 When necessary, the circumstances under which the standard is not applicable shall be clarified.

8.6.6 When necessary, the types of methods involved in the standard, applicable work content, etc. (such as screening, emergency Speed monitoring, etc.).

8.7 Normative references

8.7.1 Normative references refer to the various standards cited in the standard text. The country's abolished standards need to be quoted accurately, the standard year number and specific terms should be indicated.

8.7.2 Generally, the following expressions are used as the introductory phrase, "This standard quotes the clauses in the following documents. Any quotation without a date the effective version of the document is applicable to this standard. "

8.7.3 The cited documents are arranged in the order of GB, GB/T, HJ, and other standards, and their numbers are arranged in ascending order.

8.8 Terms and definitions

8.8.1 Definitions necessary for understanding the terms in the standard shall be given.

8.8.2 The terms and definitions should try to adopt the definitions in the national ecological environment standards and other related standards.

8.9 Principle of the method

8.9.1 Briefly describe the basic principles, method characteristics and main steps of the method.

8.9.2 When chemical reactions are involved, in principle, chemical equations should be written. If the reaction cannot be completed in one step, each One-step reaction equation.

8.10 Interference and cancellation

8.10.1 On the basis of the interference experiment, propose the links and factors that interfere with the method.

8.10.2 When there is inter...