JJG 757-2018 English PDF

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JJG 757-2018: Laboratory Ion Meters
Status: Valid

JJG 757: Historical versions

Standard ID	USD	BUY PDF	Lead-Days	Standard Title (Description)	Status
JJG 757-2018	489	Add to Cart	4 days	Laboratory Ion Meters	Valid
JJG 757-2007	RFQ	ASK	6 days	Verification Regulation of Ionometers	Obsolete
JJG 757-1991	599	Add to Cart	4 days	Verification Regulation for Ionometer	Obsolete

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Basic data

Standard ID: JJG 757-2018 (JJG757-2018)
Description (Translated English): Laboratory Ion Meters
Sector / Industry: Metrology & Measurement Industry Standard
Classification of Chinese Standard: A55
Classification of International Standard: 17.220.20
Word Count Estimation: 21,214
Date of Issue: 2018-12-25
Date of Implementation: 2019-06-25
Older Standard (superseded by this standard): JJG 757-2007
Regulation (derived from): State Administration of Markets, Announcement No.34 of 2018
Issuing agency(ies): State Administration for Market Regulation
Summary: This standard is applicable to the first verification, subsequent verification and in-use inspection of the laboratory universal ion meter for measuring the ion activity in the solution by the electrode potential method.

JJG 757-2018: Laboratory Ion Meters

---This is a DRAFT version for illustration, not a final translation. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.) will be manually/carefully translated upon your order.
Laboratory Ion Meters National Metrological Verification Regulation of the People's Republic of China Laboratory ion meter 2018-12-25 released 2019-06-25 implementation Issued by the State Administration for Market Regulation Laboratory ion meter verification regulations Replace JJG 757-2007 Focal point. National Technical Committee of Physical Chemistry Metrology Main drafting unit. China Academy of Testing Technology Participated in the drafting unit. Hulunbuir Product Quality Measurement Testing Institute This regulation entrusts the National Technical Committee of Physical Chemistry Metrology to interpret The main drafters of this regulation. Yuan Li (China Academy of Testing Technology) Xie Qi (China Academy of Testing Technology) Shao Zhixin (China Academy of Testing Technology) Participating drafters. Xijile (Hulunbuir Product Quality Measurement Testing Institute)

table of Contents

Introduction (Ⅱ) 1 scope (1) 2 Overview (1) 3 Measurement performance requirements (1) 4 General technical requirements (2) 4.1 Appearance and preliminary inspection (2) 4.2 Power-on inspection (2) 5 Measuring instrument control (2) 5.1 Verification conditions (2) 5.2 Equipment for verification (2) 5.3 Certified reference materials (3) 5.4 Verification items (3) 5.5 Verification method (4) 5.6 Verification results (7) 5.7 Verification cycle (7) Appendix A Preparation method of fluoride ion standard solution (8) Appendix B Original Record Format of Laboratory Ion Meter Verification (9) Appendix C Inner Page Format of Verification Certificate/Notification of Verification Results (14)

Introduction

This regulation is based on JJF1001-2011 "General Metrology Terms and Definitions", JJF1002-2010 "National Metrology The "Verification Regulations Compilation Rules" is the basis and basis for revising the JJG 757-2007 "Ion Meter". Compared with JJG 757-2007 "Ion Meter", in addition to editorial changes, the main technical content has the following changes. ---The name of the procedure was changed to "Laboratory Ion Meter"; ---Deleted the measurement performance requirements of class 0.2, class 0.02 and class 0.05 laboratory ion meters; ---Insulation resistance, activity indication error, output error, stability, power supply voltage adaptability, and Pointer type analog adjustment of the slope regulator range, equipotential regulator adjustment range, positioning regulator adjustment range, etc. Project; --- Deleted Appendix A, Appendix B, Appendix C, and Appendix D of the original regulations; ---Modified the environmental conditions for verification (see 5.1); ---Modified the requirements for verification equipment and certified reference materials (see 5.2, 5.3); ---Modified the measurement performance requirements (see Table 1); ---Modified the verification circuit connection diagram (see Figure 1); ---Modified the meter display value error (original display value error), meter input current (original input current), meter input Impedance (original input impedance), meter reading repeatability (original repeatability), meter pX temperature compensation error (original temperature compensation) Test methods for items such as compensator error) and temperature indication error (temperature measurement error) (see 5.5.4~5.5.9); ---Increase the instrument pX indication error and instrument pX indication repeatability test method and measurement performance requirements (see 5.5.10 and Table 1); ---The preparation method of Appendix A fluoride ion standard solution has been added. Previous releases of this regulation. ---JJG 757-2007; ---JJG 757-1991. Laboratory ion meter

1 Scope

This regulation is applicable to the initial verification and post-examination of laboratory general ion meters for measuring ion activity in solution by electrode potential method. Continued verification and in-use inspection.

2 overview

Laboratory ion meter (hereinafter referred to as instrument) is an electrochemical analyzer used to measure ion activity in solution The device is mainly composed of two parts. an electric meter and a measuring electrode. The electricity meter consists of an impedance converter, a potential amplifier, and a function regulator It is composed of display and measuring electrode including ion selective electrode and reference electrode. Use instrument to measure ion content in solution When using the comparative method to measure, first measure the battery composed of standard solution, ion selective electrode and reference electrode Calibrate the ion meter, and then use the same pair of electrodes to measure the solution to be tested, the electromotive force of the battery can be directly The connection is displayed as a potential value, or it can be displayed as pX or concentration after conversion by an electric meter. The relationship between the electromotive force E of the battery and the ion activity αx in the measured solution is. E=E0± ln10RT nF lgαx (1) Where. E0---starting potential, V; R---gas constant, 8.3144598 (48) J·K-1·mol-1; T---thermodynamic temperature, K; n---the charge number of the ion; F---Faraday constant, 96485.33289 (59) C·mol-1. E0 includes the standard electrode potential, reference electrode potential, and liquid junction potential of the ion-selective electrode. ln10RT nF It is called the theoretical slope of the electrode, expressed by k; if -lgαx is expressed by pX, then the formula (1) is. E=E0±kpX (2) When the measured ion is a positive ion, use "-" before k; when the measured ion is a negative ion, use "" before k. The initial potential E0 is adjusted by the standard solution and ion meter to eliminate. E=±kpX (3) In solution, the relationship between ion activity and ion concentration is. αx=γx·mx (4) Where. γx-activity coefficient; mx---Ion concentration.

3 Measurement performance requirements

The measurement performance requirements of the instrument are shown in Table 1. ......

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