Standard No.:	GB/T 5750.2-2023
English Name:	Standard examination methods for drinking water—Part 2：Collection and preservation of water samples
Chinese Name:	生活饮用水标准检验方法 第2部分：水样的采集与保存
Chinese Classification:	C51    Environmental sanitation
Professional Classification:	GB    National Standard
Issued by:	SAMR; SAC
Issued on:	2023-03-17
Implemented on:	2023-10-1
Status:	valid
Superseding:	GB/T 5750.2-2006 Standard Examination Methods for Drinking Water - Collection and Preservation of Water Samples
Language:	English
File Format:	PDF
Word Count:	6000 words
Price(USD):	180.0
Delivery:	via email in 1~3 business day

Foreword This document is drafted in accordance with the provisions of GB/T 1.12020 "Standardization Guidelines, Part 1 Structure of standardized documents and starting rules" This document is GB/T 5750 "Standard Test Methods for Drinking Water", Part 2. 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 5750.2-2006 "Standard Test Methods for the Collection and Storage of Drinking Water Samples" and GB/T 5750.2-2006, in addition to structural adjustments and editorial changes, the main technical changes are as follows Changed the "Notes" (see 4.12, 2006 version of 7.1.3). a) changed the sampling volume of conventional and extended indicators of drinking water (see Table 1, 2006 version of Table 1) b) change the sampling container and the method of preservation of water samples (see Table 2, Table 2 of the 2006 edition). Please note that some of the contents of this document may be patent related. The issuing agency of this document does not assume responsibility for identifying patents This document is proposed and attributed by the National Health and Wellness Commission of the People's Republic of China. Introduction GB/T 5750 "Standard Test Methods for Drinking Water" as the recommended national standard for drinking water testing technology and GB 5749 "Drinking Water Sanitation Standards" package, is an important technical support for the implementation of GB 5749, the implementation of drinking water health and safety assessment to provide testing 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 of 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 basic principles, measures and requirements for sample collection, preservation, management, transportation and sampling quality control of drinking water and water source water. This document applies to the collection and preservation of samples of drinking water and water source water. 2 normative references This document does not have normative citation documents 3 terms and definitions This document does not need to define the terms and definitions 4 water sample collection 4.1 Sampling plan Sampling should be based on the purpose and task of water quality inspection before the development of sampling plan, including: sampling purposes, test indicators, sampling time, sampling locations, sampling methods, sampling frequency, the number of samples, sampling containers and cleaning, sampling volume, sample preservation methods, sample labeling, on-site determination of indicators, sampling quality control, sample transportation tools and storage conditions 4.2 Selection of sampling containers 4.2.1 should be based on the characteristics of the components to be measured to select the appropriate sampling container. 4.2.2 container or container lid (plug) material should be chemically and biologically inert, should not react with the components of the water sample, the container wall and container lid (plug) does not dissolve, absorb or adsorb the components to be measured. 4.2.3 sampling container should be able to adapt to changes in ambient temperature, with a certain degree of seismic performance. 4.2.4 sampling container size and sampling volume appropriate, tightly sealed, and easy to open, and easy to clean. 4.2.5 It is advisable to use thin-mouthed containers as far as possible, the container cover (plug) material should be unified with the container material. In special cases need to use cork or rubber stopper, the application of stable metal foil or polyethylene film wrapped, and should have a wax seal (except for the detection of petroleum water samples). Collection of samples for organic and some microbial detection can not be used for rubber stopper containers, water samples are alkaline can not be used for the collection of glass stopper containers. 4.3 Washing of sampling containers 4.3.1 Determination of general physical and chemical indicators of the sampling container washing The container will be cleaned with water and detergent, remove dust and grease after rinsing clean with tap water, and then soaked with a mass fraction of 10% nitric acid (or hydrochloric acid) for more than 8h, remove the drainage and rinse with tap water 3 times and wash well with pure water. 4.3.2 Determination of organic matter indicators sampling container washing Soak in potassium dichromate solution for 24h, then rinse with tap water, rinse with pure water and drained and placed in the oven at 180C for 4h, cooled and ready for use; if necessary, then rinse several times with purified n-alkane two ketones and methanol 4.3.3 Determination of microbial indicators of the washing and sterilization of sampling containers 4.3.3.1 Container washing: wash the container with tap water and detergent, and rinse thoroughly with tap water and soak in nitric acid (or hydrochloric acid) with a mass fraction of 10% for more than 8h, then wash with tap water and pure water in turn. 4.3.3.2 Vessel sterilization Vessel sterilization can be done by dry heat or autoclaving. Dry heat sterilization is required to maintain 2h at 160C; high steam sterilization is required to maintain 15min at 121C. If the containers after high steam sterilization are not used immediately, they should be placed in a 60C box to dry the condensate in the bottles. The sterilized containers should be used within 2 weeks. 4.4 Sampler 4.4.1 for water samples with a certain depth of water source collection, sampling should be selected before the appropriate sampler 4.4.2 plastic or glass samplers and rubber tubes for sampling, latex or silicone tubes can be washed in accordance with .3.1 spare. 4.4.3 metal samplers, should first use detergent to remove grease, and then rinse clean with tap water and pure water in turn and then dry. 4.4.4 Special sampler cleaning method can refer to the instrument manual. 4.5 General requirements for the collection of water samples 4.5.1 Physical and chemical indicators Sampling should be used before the collection of water samples to wash the sampler, containers and plugs 2 ~ 3 times (except for the determination of oil water samples). 4.6 factory water collection Factory water sampling points should be set in the factory water into the transmission (distribution) pipeline before. 4.8 end of the water collection The end of the water sampling point should be set in the factory water transmission and distribution pipeline network to the user's tap. Sampling, it is usually appropriate to release the water for a few minutes to exclude sediments, special circumstances can be extended to release the water time. Collection of samples for microbiological indicators should be disinfected before the faucet. 4.9 secondary water supply collection Can be based on the actual work required in the tank (or cistern) inlet, outlet and (or) end of the water sample collection 4.10 Collection of decentralized water supply Can be collected in accordance with the actual use of water collection points or user storage containers 4.11 Filtration and centrifugal separation of water samples In the sampling or shortly after sampling, if necessary, filter paper, filter membrane, sand core funnel or glass fiber filter samples or centrifugal separation of samples to remove the suspended matter, sediment, algae and other microorganisms. In the analysis, the purpose of filtration is to distinguish the dissolved state and adsorption state, in the selection of filters to pay attention to the possible loss of adsorption, such as the measurement of organic items, the general choice of sand core funnel and glass fiber filtration, the determination of inorganic items, it is commonly used 0.45um filter membrane filtration. 4.12 Precautions 4.12.1 collection of several types of testing indicators of water samples, should be collected first for microbiological indicators of water samples 4.12.2 sampling should be removed from the faucet filter and (or) fogging nozzle, etc. 4.12.3 sampling can not stir the sediment under the water. 5 water samples preservation 5.1 Preservation measures Should be based on the determination of indicators to choose the appropriate preservation methods, mainly refrigeration, light and adding preservatives, etc. 5.2 Preservative 5.2.1 preservative should not interfere with the determination of the substances to be measured, can not affect the concentration of the substances to be measured. If it is a liquid, it should be corrected for changes in volume. The purity and grade of the preservative should meet the requirements of the analysis. 5.2.2 preservative can be added to the sampling container in advance, or as soon as possible after sampling. Perishable preservative should not be added in advance. 5.3 Preservation conditions 5.3.1 The preservation period of water samples depends mainly on the concentration of the substances to be measured, chemical composition and physicochemical properties 5.3.2 Due to the components of water samples, the concentration and nature of the target analytes are different, test methods, water samples should be preserved with priority reference to the provisions of the test method, if the test method does not specify, can refer to Table 2. when the water samples contain residual chlorine and other disinfectants interfere with the determination of the need to add ascorbic acid or sodium thiosulfate and other reducing agents, the concentration of disinfectants should be set according to the appropriate amount of addition, in order to achieve the elimination of interference. purpose. 5.3.3 Water samples should be measured as soon as possible after collection. Water temperature and residual chlorine and other indicators should be measured in the field, the rest of the indicators should also be measured within the specified time. 6 sample management and transport 6.1 Sample management 6.1.1 In addition to the samples used for on-site measurement, the rest of the water samples should be shipped back to the laboratory for testing and analysis. In the transport of water samples and laboratory management process should ensure that their properties are stable, intact, free from contamination, damage and loss. 6.1.2 field test samples: should be detailed records of field test results and properly stored. 6.1.3 laboratory test samples: sampling records and labels should be accurately filled out, and the label is attached to the sampling container, indicating the water sample number, sampler, date, time and location and other relevant information. In sampling, all field surveys and sampling should also be recorded, including the purpose of sampling, sampling locations, sample types, numbers, quantities, sample preservation methods and sampling climate conditions. 6.2 Sample transport 6.2.1 water samples collected should be sent back to the laboratory immediately after the test analysis. Sample transport should be based on the geographical location of the sampling point and the determination of the maximum preservation time of the indicators to choose the appropriate mode of transport, before the start of field sampling work should be arranged for transport to prevent delays. 6.2.2 Samples should be checked with the sample registration form, sample labels and sampling records one by one before shipment, and sorted into boxes after checking. 7 Sampling quality control 7.1 The purpose of quality control To ensure the quality of the whole sampling process, to prevent the sample collection process of water samples are contaminated or trait changes 7.2 Field blanks 7.2.1 field blank is the sampling site with pure water as a sample, in accordance with the sampling methods and requirements for the determination of indicators, bottled under the same conditions as the sample, preservation and transport, until sent to the laboratory analysis. 7.2.2 Through the field blank and laboratory blank measurement results, to master the sampling process and the environmental conditions of the sample of the concentration of the substances to be measured. 7.2.3 The pure water used in the field blank should be clean special containers, brought to the sampling site by the sampling personnel, and care should be taken to prevent contamination during transportation. 7.2.4 Each batch of samples at least one field blank. 7.3 Transport Blanks 7.3.1 Transport blank is pure water as a sample, from the laboratory to the sampling site and back to the laboratory. Transport blanks can be used to grasp the sample transport, field processing and storage during the possible contamination. 7.3.2 Each batch of samples set at least one transport blank. 7.4 Field Parallel Samples 7.4.1 Field parallel samples are collected under the same sampling conditions and sent to the laboratory for analysis. 7.4.2 field parallel samples to pay attention to control the sampling operation and conditions of the same. For water samples of non-homogeneous substances or uneven distribution of pollutants in the sample filling should shake the sampler, so that the sample remains uniform. 7.4.3 The number of field parallel samples is generally controlled in more than 10% of the total number of samples.

Foreword Introduction 1 Scope 2 normative references 3 terms and definitions 4 water sample collection 5 water samples preservation 6 sample management and transport 7 Sampling quality control