Standard No.:	GB/T 5750.4-2023
English Name:	Standard examination methods for drinking water—Part 4：Organoleptic and physical indices
Chinese Name:	生活饮用水标准检验方法 第4部分：感官性状和物理指标
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 5750.4-2006 Standard examination methods for drinking water - Organoleptic and physical parameters
Language:	English
File Format:	PDF
Word Count:	21500 words
Price(USD):	700.0
Delivery:	via email in 1~5 business day

Foreword This document is drafted in accordance with the provisions of GB/T1.12020 "Guidelines for standardization work, Part 1: the structure of standardized documents and starting rules". This document is part 1 of GB/T5750 "Standard Test Methods for Drinking Water". GB/T5750 has issued 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/T5750.4-2006 "Standard test methods for drinking water sensory properties and physical indicators" compared with GB/T5750.4-2006, in addition to structural and editorial changes, the main technical changes are as follows a) increased the "terms and definitions" (see Chapter 3). b) increased the six test methods (see 6.2, 6.3, 12.2, 12.3, 13.3, 13.4). c) deleted a test (see 9.2 of the 2006 version) Please note that some of the contents of this document may involve patents. The issuing authority 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/T5750 "Standard Test Methods for Drinking Water" as a recommended national standard for drinking water testing technology, and GB5749 "Drinking Water Sanitation Standards" supporting, is an important technical support for GB5749, for the implementation of GB5749 to carry out health and safety evaluation of drinking water to provide test methods. GB/T5750 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 sample collection, preservation, management, transport and sampling quality control of the basic principles, measures and requirements. Part 3: Water quality analysis quality control. 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 describes the drinking water color, turbidity, odor and taste, visible to the naked eye, pH, conductivity, total hardness, total dissolved solids, volatile phenols, anionic synthetic detergent determination method and water color, turbidity, odor and taste, visible to the naked eye, pH, conductivity, total hardness, total dissolved solids, volatile phenols (4-aminoantipyrine trichloromethane extraction spectrophotometry) , anionic synthetic detergents determination method. This document applies to the determination of sensory properties and physical indicators in drinking water and (or) water sources 2 normative reference documents The following documents constitute the essential provisions of this document through the normative references in the text. Among them, attention to the period of reference documents, only the date corresponding to the version applicable to this document; do not note the date of reference documents, the latest version (including all the revision of the list) applicable to this document. GB/T 5750.1 Part 1: General Guidelines for the standard test methods for domestic drinking water GB/T 5750.3 Standard test methods for drinking water Part 3: Quality control of water quality analysis GB/T 6682 Analytical laboratory water specifications and test methods 3 terms and definitions GB/T 5750.1 and GB/T 5750.3 defined terms and definitions apply to this document. 4 Colorimetric 4.1 Platinum - drill standard colorimetric method 4.1.1 Minimum detection value Water samples without dilution, the method of the minimum detection of chromaticity of 5 degrees, the determination range of 5 degrees ~ 50 degrees 5 turbidity 5.1 Scattering method-Former book standard 5.1.1 Minimum detection value The method of turbidity minimum detection value of 0.5 scattering turbidity units (NTU). Turbidity is a reflection of the source water and drinking water physical properties of an indicator, to indicate the degree of turbidity of water. Turbidity of water is due to the presence of suspended or colloidal substances in the water, or both caused by the optical scattering or absorption behavior. 5.1.2 principle Under the same conditions with the intensity of light scattered by the standard suspension of forma fat and the intensity of light scattered by the water sample for comparison. The greater the intensity of the scattered light, the higher the turbidity is indicated. 5.1.3 Reagents Warning: Arachidonic acid is carcinogenic, avoid inhalation and skin contact! 5.1.3.1 Pure water: Take evaporated water and filter it through 0.22um membrane and use it. 6 odor and taste 6.1 smell gas and taste method 6.1.1 Apparatus and equipment Conical flask:250mL. 6.1.2 Test procedure 6.1.2.1 Original water samples of odor and taste Take 100mL water samples, placed in a 250L-shaped bottle, vibration broadcast from the bottle after the smell of water, with appropriate text description, and according to six levels of record of its intensity, see Table 2. Note: analysis in a well-ventilated, odor-free environment, analysts 30m before the test to avoid eating and drinking or smoking, suffering from colds, overcontribution disorders or other related problems do not participate in the smell test. Avoid using soap, perfume, face dressing, etc. to avoid interference of foreign odors in the test. After sniffing samples with high odor intensity, rest for more than 15 min and continue the analysis, and stop the test when the analyst is tired and rest in a room without odor. At the same time, take a small amount of water samples into the mouth, do not swallow, taste the taste of water, be described, and record the intensity according to six levels, see Table 2. 6.1.2.2 The original water boiling odor and taste The above conical bottle of water samples heated to the beginning of boiling, immediately remove the conical bottle, slightly cold, according to the above method of smell and taste, with appropriate text to describe, and according to the six levels of the intensity of the record, see Table 2. 7 Naked eye visible matter 7.1 Direct observation method Shake the water sample well, pour it into a clean and transparent conical bottle and observe it directly in a bright light, and record the visible matter observed by the naked eye. 8pH value 8.1 Glass electrode method 8.1.1 Principle The pH value can be determined accurately to 0.01 by this method. DH value is the logarithmic value of the inverse of hydrogen ion activity in water. Water color, turbidity, residual chlorine, oxidizing agent, reducing agent, higher salt content do not interfere with the determination, but in the strong alkaline solution, when there are a large number of sodium ions will produce errors, so that the reading is low. The glass electrode is used as the indicator electrode and the saturated mercury electrode is used as the reference electrode, which is inserted into the solution to form a primary cell. When the concentration of hydrogen ion changes, the electric potential between the glass electrode and the glycury electrode also changes, at 25C, each unit of pH scale is equivalent to 59.1mV electric potential change value, which is directly expressed as pH reading on the instrument. The instrument is equipped with a temperature difference compensation device. 8.1.2 Reagents Unless otherwise specified, the water used for the experiment is secondary water as specified in GB/T6682, ready for use. 9 Conductivity 9.1 Electrode method 9.1.1 Principle Conductivity is a number to express the ability of aqueous solution to conduct current. It has a close relationship with the minerals in the water, can be used to detect the living Drinking water and its source of water changes in the concentration of dissolved minerals and estimate the number of ionic compounds in water. The conductivity of water is proportional to the concentration of electrolytes and has a linear relationship. Most inorganic salts in water exist in ionic state, which is a good conductor of electricity, but organic substances do not dissociate or dissociate very weakly, and conduct electricity very weakly, so the conductivity does not reflect this kind of pollution factors. The general conductivity of natural water is between 50S/m~1500S/m, and the water containing high inorganic salts can be more than 10000S/cm. The characteristics of dissolved electrolytes in water, concentration and water temperature are closely related to the determination of conductivity. Therefore, the test conditions and the selection and installation of the conductivity meter electrode can affect the precision and accuracy of the measured conductivity. 10 Total hardness 10.1 Disodium ethylenediaminetetraacetic acid titration method 10.1.1 Minimum detectable mass concentration The minimum detection quality of this method is 0.05mg, if 50mL water sample is taken for determination, the minimum detection quality concentration is 1.0mg/L. The main interfering elements of this method iron, manganese, aluminum, copper, nickel, drill and other metal ions can make the indicator fade or the end point is not obvious. Sodium sulfide and potassium cyanide can conceal the interference of heavy metals, hydrochloric acid selective amine can make high iron ions and high-valent manganese ions reduced to low-valent ions and eliminate their interference. 10.1.2 Principle Calcium and magnesium ions in the water sample and chromium black T indicator to form purple-red integration, the instability constant of these compounds is greater than the instability constant of calcium and magnesium chelate of ethylenediaminetetraacetic acid. When the pH=10, disodium diamine tetrazolium acid firstly forms the integration with calcium ion, then with magnesium ion, and the solution shows the pure blue color of chromium black T indicator when titrating to the end point. 10.1.3 Reagents 11 Total dissolved solids 11.1 Weighing method 11.1.1 Principle 11.1.1.1 The water sample is filtered and dried at a certain temperature, and the resulting solid residue is called total dissolved solids, including non-volatile soluble salts, organic matter and insoluble particles that can pass through the filter. 11.1.1.2 Drying temperature is generally used 105C3C. But 105C temperature can not completely remove the crystalline water contained in the salts in highly mineralized water samples. The use of 180C3C drying temperature, you can get more accurate results. 11.1.1.3 when the total dissolved solids in the water sample contains a large amount of calcium chloride, calcium nitrate, magnesium chloride, magnesium nitrate, because these compounds have a strong hygroscopicity so that the weighing can not be constant mass, when the water sample can be added to the appropriate amount of sodium carbonate solution and get improved. 12 Volatile phenols 12.14 aminoantipyrine trichloromethane extraction spectrophotometry 12.1.1 Minimum detection mass concentration The minimum detection mass of this method is 0.5g volatile class (in phenol). If 250L water samples are taken, the minimum detection mass concentration is 0.002mg/L volatile phenols (phenol). Interfering substances and their elimination methods: reducing sulfides, oxidizers, aniline compounds and petroleum in water interfere with the determination of phenols. Sulfides by acidification and the addition of copper sulfate in the distillation and volatile phenols separated; residual chlorine and other oxidizing agents can be added to the sampling of ferrous sulfate or sodium arsenite reduction. Aniline in acidic solution to form salts are not evaporated. Petroleum can be removed under alkaline conditions after extraction with organic solvents. 13 Anionic synthetic detergents 13.1 Methylene blue spectrophotometric method 13.1.1 Minimum detection mass concentration This method uses sodium dodecylbenzene sulfonate as the standard, the minimum detection mass of anionic synthetic detergent in the water sample is 5 g. If 100 mL of water sample is taken for determination, the minimum detection mass concentration is 0050 mg/L. Substances that can react with methylene blue have interference with this method. Phenol, organic sulfate, sulfonate, phosphate and a large number of chlorides (2000mg) nitrate (5000mg) thiocyanate, etc. can make the results high 13.1.2 Principle Methylene blue dye in aqueous solution with anionic synthetic detergent to form a blue compound that can be easily extracted by organic solvents. The unreacted methylene blue then remains in the aqueous solution. The content of the anionic synthetic detergent is determined according to the intensity of the blue color in the organic phase.

Foreword Introduction 1 Scope 2 normative reference documents 3 terms and definitions 4 Colorimetric 5 turbidity 6 odor and taste 7 Naked eye visible matter 8 pH value 9 Conductivity 10 Total hardness 11 Total dissolved solids 12 volatile phenols 13 anionic synthetic detergents