Foreword
This document is drafted in accordance with the provisions of GB/T1.1-2020 "Guidelines for Standardization Work Part 1 Structure of Standardization Documents and Drafting Rules".
This document is part 3 of GB/T 5750 "Standard Test Methods for Drinking Water". GB/T 5750 has published the following parts.
Part 1:General Provisions.
Part 2: the collection and preservation of water samples.
Part 3: Quality control of water quality analysis.
Part 4: sensory properties and physical indicators.
Part 5: inorganic non-metallic indicators.
Part 6: metal and metal-like indicators.
Part 7: organic composite indicators.
Part 8 organic indicators.
Part 9: Pesticide indicators.
Part 10: Disinfection by-product indicators.
Part 11: Disinfectant indicators.
Part 12: Microbial indicators
Part 13: Radioactive indicators.
This document replaces GB/T 5750.3-2006 "standard test methods for drinking water quality control of water analysis", compared with GB/T 5750.3-2006, in addition to structural adjustments and editorial changes, the main technical changes are as follows.
a) increased the terminology and definitions (see Chapter 3).
b changed the quality control requirements (see Chapter 4, 2006 version of Chapter 3)
Added titrimetric detection limits (see 6.) c)
dChanged calibration and regression (see 6.6, Chapter 5 of the 2006 edition)
Added quality control method for "proficiency testing" (see 7.6); e)
f) Changes to the reporting of assay results (see Chapter 9, 9.1 of the 2006 edition).
Please note that some of the contents of this document may be patent related. The publisher of this document does not assume responsibility for identifying patents, and this document is proposed by and attributed to the National Health Care Commission of the People's Republic of China.
Introduction
GB/T 5750 "Standard Test Methods for Drinking Water" as a recommended national standard for drinking water testing technology, and GB 5749 "Drinking Water Sanitation Standards" supporting, is an important technical support for GB 5749, for the implementation of GB 5749, to carry out health and safety evaluation of drinking water to provide test methods.
GB / T 5750 consists of 13 parts.
Part 1: General Provisions. The purpose is to provide the basic principles and requirements of water quality testing.
Part 2: the collection and preservation of water samples. The purpose is to provide water samples collected, preservation, management, transport and sampling quality control of the basic principles, measures and requirements.
Part 3: quality control of water quality analysis. The purpose is to provide water quality inspection and testing laboratory quality control requirements and methods
Part 4: Sensory traits and physical indicators. The purpose is to provide sensory traits and physical indicators of the corresponding test methods.
Part 5: inorganic non-metallic indicators. The purpose is to provide inorganic non-metallic indicators of the corresponding test methods
Part 6: Metals and metal-like indicators. The purpose is to provide metal and metal-like indicators of the corresponding test methods
Part 7: Organic composite indicators. The purpose is to provide a comprehensive index of organic substances corresponding test methods.
Part 8: organic indicators. The purpose is to provide the corresponding test methods for organic indicators.
Part 9: pesticide indicators. The purpose is to provide the corresponding test methods for pesticide indicators.
Part 10: Disinfection by-products indicators. The purpose is to provide the corresponding test methods for disinfection by-product indicators
Part 11: Disinfectant indicators. The purpose is to provide the corresponding test methods for disinfectant indicators
Part 12: Microbiological indicators. The purpose is to provide the corresponding test methods for microbial indicators
Part 13: radioactive indicators. The purpose is to provide the corresponding test methods for radioactive indicators
1 Scope
This document specifies the quality of drinking water and water quality inspection and testing laboratory quality control requirements and methods This document applies to the determination process of drinking water and water quality.
2 normative reference documents
The content of the following documents through the normative references in the text and constitute the essential provisions of this document. Among them, note the date of the reference file, only the date corresponding to the version applicable to this document; do not note the date of the reference file, its latest version (including all the change orders) applicable to this document.
GB/T 4883 statistical processing of data and interpretation of normal sample outliers judgment and processing
GB 5749 sanitary standards for drinking water
GB/T 5750.1 Standard test methods for drinking water for domestic use Part 1: General Provisions
GB/T 5750.2 standard test methods for drinking water Part 2: collection and preservation of water samples
GB/T 8170 numerical modification rules and limit values of the representation and determination
GB/T 27418 measurement uncertainty assessment and expression
GB/T 32465 chemical analysis method verification confirmation and internal quality control requirements
CNAS-GL 027:2018 Internal quality control guidelines for chemical analysis laboratories - Application of control charts
3 Terminology and definitions
The following terms and definitions are applicable to this document.
4 Quality control requirements
4.1 The purpose of quality control is to reduce the error in the analysis to a certain limit in order to obtain accurate and reliable test results.
4.2 Quality control should be throughout the entire process of water quality analysis, such as sample collection and preservation, sample analysis, data processing, etc. Physical and chemical indicators microbial indicators, radioactive indicators test quality control should be in line with GB/T 5750.1 and GB/T 5750.2 and related indicators test methods and related requirements.
4.3 The laboratory should be validated before the first use of standard methods.
4.4 quality control is the discovery, control and analysis of the process of generating sources of error, used to control and reduce errors, can be achieved by using standard substances or quality control samples, comparison tests (such as personnel comparison, method comparison, instrument comparison, sample retesting, etc.), participation in proficiency testing programs or inter-laboratory comparison, parallel double sample method, spiked recovery method and other effective technical methods to ensure that the analytical results The accurate and reliable.
5 Analytical errors
5.1 Classification of errors in the analysis of the error there are three categories: errors caused by the influence of systematic factors, errors caused by the influence of random factors and errors caused by negligent behavior.
5.2 Representation of the error
6 Quantitative limit of the method
The method quantitative limit is determined mainly from its credibility considerations, such as whether the test is based on regulatory requirements, target measurement uncertainty and acceptable guidelines. It is usually recommended that the blank value plus 10 times the reproducibility standard deviation be used as the method quantification limit, or 3 times the detection limit or 50% above the minimum spiked amount used in the method confirmation as the method quantification limit. For specific matrices and methods, the method limits of quantification may vary between laboratories or within the same laboratory due to the use of different equipment, techniques and reagents. In spectrophotometric methods, the mass or mass concentration corresponding to a net absorbance of 0.020 is usually used as the limit of quantification of the method. For physical and sensory methods, the method limits of quantification are determined on a case-by-case basis. Laboratories may also use other parameters according to industry rules.
6.6 Calibration and Regression
6.6.1 Calibration Curve
Calibration curve describes the quantitative relationship between the concentration or content of the substance to be measured and the response value of the detection instrument or the indicated amount, divided into "working curve" (standard solution processing procedures and analytical procedures are identical to the sample) and "standard curve" (standard solution processing procedures (the standard solution procedure is omitted compared with the sample, such as sample pretreatment)
7 Quality control methods
7.1 Quality control chart method
The most important control charts used in chemical analysis laboratories are of two types, i.e. X-charts (single value or mean value charts) and R-charts (extreme difference charts). Blank value-X-plots and recovery X-plots are special applications of X-plots. Figure 1 shows the most commonly used X-plot drawn from mean values.
8 Data processing
8.1 Judgment and processing of outliers
8.1.1 Outliers are judged and processed according to the implementation of GB/T4883.
8.1.2 Grubbs (Grubbs) test can be used to test the consistency of the mean value of multiple measurements and remove outliers in the mean value of multiple measurements, can also be used to test the consistency of a group of measurements and remove outliers in a group of measurements, the number of detected outliers does not exceed 1.
8.2 Measurement results of numerical modifications
8.2.1 Measure the value of the results in accordance with GB/T8170 implementation.
8.2.2 Valid numbers are used to indicate the effective meaning of the measurement figures. Refers to the actual number of measurements can be measured, the value of the valid numbers, the penultimate digit above the number should be reliable (certain), only the last digit is suspicious (uncertain). The number of digits of valid numbers cannot be arbitrarily added or deleted.
9 measurement results of the report
9.1 measurement results should be measured using the People's Republic of China legal units of measurement.
9.2 chemical analysis indicators of the measurement results are generally expressed in milligrams per liter (mg / L), the concentration is lower, then micrograms per liter (jag / L)
9.3 The measurement results of radioactive indicators are expressed in Bq per liter (Bq/L).
10 Data correctness judgment
Various ions in the body of water in mutual influence, mutual restraint of equilibrium, any change in the influence of factors, will inevitably make the original equilibrium change to reach a new equilibrium. Therefore, the use of chemical equilibrium theory, such as charge equilibrium, precipitation equilibrium, etc., can be timely detection of large analytical errors and mistakes, control and verification of the correctness of the data to make up for the quality control can not provide reliable control of each sample. Table 2 lists a variety of chemical equilibria in the water, error calculation formulae and evaluation criteria. For the convenience of calculation, the correctness check procedure of the measurement data can be established, and the calculation results of the correctness check can be reported along with the measurement results.
Bibliography
Foreword
Introduction
1 Scope
2 normative reference documents
3 Terminology and definitions
4 Quality control requirements
5 Analytical errors
6 Quantitative limit of the method
7 Quality control methods
8 Data processing
9 measurement results of the report
10 Data correctness judgment
Bibliography
