is是什么USP34 645 水的电导率(中英文)

2021年1月20日发(作者：paw)
USP34
<645>
水的电导率（中英文）

<645> WATER CONDUCTIVITY
水的电导率

Electrical conductivity in water is a measure of the ion- facilitated electron flow through it. Water
molecules dissociate into ions as a function of pH and temperature and result in a very
predictable conductivity.

水的电导能力是对水中离子 化电子的一种测量。离解为离子的水分子是
pH
值、温度的函数，它
导致可预期的电导 率。

Some gases, most notably carbon dioxide, readily dissolve in water and interact to form ions,
which predictably affect conductivity as well as pH. For the purpose of this discussion, these
ions and their resulting conductivity can be considered intrinsic to the water.

一些气体，特别是二氧化碳，容易溶于水中并产生反应形成离子 ，
对电导率产生影响。
在本讨论
中，这些离子和其对电导率的影响结果可以认为是水的 内在本质。

Water conductivity is also affected by the presence of extraneous ions. The extraneous ions
used in modeling the conductivity specifications described below are the chloride and sodium
ions. The conductivity of the ubiquitous chloride ion (at the theoretical endpoint concentration
of 0.47 ppm when it was a required attribute test in
USP XXII
and earlier revisions) and the
ammonium ion (at the limit of 0.3 ppm) represent a major portion of the allowed water impurity
level. A balancing quantity of cations, such as sodium ions, is included in this allowed impurity
level to maintain electroneutrality. Extraneous ions such as these may have significant impact
on the water's chemical purity and suitability for use in pharmaceutical applications. The
procedure in the section
Bulk Water
is specified for measuring the conductivity of waters such
as Purified Water, Water for Injection, Water for Hemodialysis, and the condensate of Pure
Steam. The procedure in the section
Sterile Water
is specified for measuring the conductivity
of waters such as Sterile Purified Water, Sterile Water for Injection, Sterile Water for Inhalation,
and Sterile Water for Irrigation.

水的电导率还受到外来离子的影响，
下面所述的包括在电导率质量标准中的外来离子包括氯离子
和钠离子。无所不在的钠离子（根据
USP22
和更早版本测试其理论终点浓度
0.47ppm
）和铵离
子（限度 为
0.3ppm
时）的电导率代表了水中允许杂质的主要组成部分。阳离子数量平衡，例如钠离子，
包括在允许杂质水平内以保持电中性。
象这些外来离子对水的化学纯度和水在制药 用途
适用性可能具有显著的影响。
在“散装水”部分的检测程序用于测量以下水的电导率，如纯化水、
注射水、透析用水、纯蒸汽冷凝水。在“无菌水”部分中的检测程序用于测量以下水的电 导率，
如无菌纯化水、注射用无菌水、吸入剂用无菌水和冲洗剂用无菌水。

Online conductivity testing provides real-time measurements and opportunities for real-time
process control, decision, and intervention. Precaution should be taken while collecting water
samples for off-line conductivity measurements. The sample may be affected by the sampling
method, the sampling container, and environmental factors such as ambient carbon dioxide
concentration and organic vapors.

在线电导率检测提供了一种实时测量，
可以有机会进行实时过程控制、
决策和干预。< br>在取样进行
离线电导率测量时，
需要注意样品可能会受到取样方法的影响，
取样 容器、
环境因素如空气中二
氧化碳浓度和有机蒸汽等。

INSTRUMENT SPECIFICATIONS AND OPERATING PARAMETERS
仪器标准和操作参数

Water conductivity must be measured accurately using calibrated instrumentation. The
conductivity cell constant, a factor that represents the geometrical properties of the
conductivity sensor, must be known within
±
2%. The cell constant can be verified directly by
using a solution of known or traceable conductivity, or indirectly by comparing the instrument
reading taken with the conductivity sensor in question to readings from a conductivity sensor of
known or traceable cell constant.

水的电导率测量应使用经过校正 的仪器进行准确测量。
电导率电极常数，
代表电导率电极的几何
级性能，误差必须在±
2%
内。电极常数可以直接采用已知可追溯的电导率溶液确认，或间接地
通过将待确认 电极在仪器中的读数与已知或可追溯常数的电导率电极读数进行比较来确认。

Meter calibration is accomplished by replacing the conductivity sensor with NIST (or equivalent
local national authority) -traceable precision resistors (accurate to
±
0.1% of the stated value)
or an equivalently accurate adjustable resistance device, such as a Wheatstone Bridge, to give
a predicted instrument response. Each scale on the meter may require separate calibration
prior to use. The frequency of recalibration is a function of instrument design, degree of use,
etc. However, because some multiple-scale instruments have a single calibration adjustment,
recalibration may be required between each use of a different scale. Excluding the conductivity
sensor cell constant accuracy, the instrument accuracy must be
±
0.1
μ
S/cm.

计量校正是通过用一个
NIST
（或等同的当地国家机构）可追溯精度电阻（准确至标示值的
±
0.1%）或相当准确度可调整的电阻装置代替，例如惠斯通电桥，给出一个预期的仪器反应。
计量器具上每 个刻度均需要在使用前分别校正。
重新校正的频次与仪器的设计、
使用程度等成比
例。 但是，因为一些多量程仪器具有单个校正调整功能，
使用不同刻度时可能需要重新校正。
不考虑电导率电极常数准确度，仪器准确度必须为±
0.1
μ
S/cm
。

In order to increase the measurement accuracy on the conductivity ranges used, which can be
large, and to ensure a complete equipment calibration, it is suggested that periodic verification
of the entire equipment be performed. This could be done by comparing the
conductivity/resistivity values displayed by the measuring equipment with those of an external
calibrated conductivity-measuring device. The two nontemperature-compensated conductivity
or resistivity values must be equivalent to within
±
20% of each other, or at a difference that is
acceptable on the basis of product water criticality and/or the water conductivity ranges in
which the measurements are taken. The two conductivity sensors should be positioned close
enough together to measure the same water sample in the same environmental conditions.

为了提高所用的电导率范 围的测量准确度，
该范围可能会很大，
以及保证仪器校正完整性，
建议
对整个 仪器进行周期性确认。该确认可以将仪器所显示的电导率
/
电阻值与经过外部校正的电导
率
/
电阻测量装置进行比较。两个非温度补偿电导率值或电阻值差异必须在±
20%
以内，或其差
异基于产品用水的关键性和
/
或所测量的水电导率范围评估为可 接受的。两个电导率电极位置应
足够近以使所测量的相同水样在相同的环境条件下。

In addition to the verification method performed in non-temperature-compensated mode, a
similar verification performed in temperature- compensated mode could be performed to
ensure an appropriate accuracy of the equipment when such a mode is used for trending or
other purposes.

除了对非温度补偿模式的方法确认，
对温度补偿模式进行类似确 认可以保证仪器在用于其它用途
时的准确度。

Because temperature has a substantial impact on conductivity readings of specimens at high
and low temperatures, many instruments automatically correct the actual reading to display
the value that theoretically would be observed at the nominal temperature of 25
℃
. This is
typically done using a temperature sensor embedded in the conductivity sensor and an
algorithm in the instrument's circuitry.
< br>由于温度对电导率读数影响，许多仪器具有自动温度补偿功能，会将实际读数校正为
25
度时读
数显示。一般是在电导率电极上附加了一个温度电极，对仪器信号回路进行了一个运算。

This temperature compensation algorithm may not be accurate. Conductivity values used in
this method are nontemperature-compensated measurements. Temperature measurement is
required for the performance of the
Stage 1
test. It may be made using the temperature sensor
embedded in the conductivity cell sensor. An external temperature sensor positioned near the
conductivity sensor is also acceptable. Accuracy of the temperature measurement must be
±2℃
.

这种温度补偿运算 可能不是很精确。
本方法中所用的电导率值是未经温度补偿所检测的。
在第一
阶段检测 时，
需要同时测定温度，
可是使用与电导率电极结合在一起的温度电极，
也可以在接近
电导率电极的地方放置一个温度电极。温度测度准确度必须为±2℃。

The procedures below shall be performed using instrumentation that has been calibrated, has
conductivity sensor cell constants that have been accurately determined, and has temperature
compensation function that has been disabled. For both online and offline measurements, the
suitability of instrumentation for quality control testing is also dependent on the sampling
location(s) in the water system. The selected sampling instrument location(s) must reflect the
quality of the water used.

以下程序所使用的仪器应 经过校正，
电导率电极常数应准确确认，
温度补偿功能应关闭。
不管是
在线测 量还是离线测量，
仪器检测适用性还取决于样品在水系统中所处的位置，
选取的取样点应
能反映所使用水的质量。

BULK WATER
散装水

The procedure and test limits in this section are intended for Purified Water, Water for Injection,
Water for Hemodialysis, the condensate of Pure Steam, and any other monographs which
specify this section.

本部分中所包括的测试 程序和限度适用于纯化水、
注射用水、
血透析水、
纯蒸汽冷凝水及其它引
用本 部分的其它各论。

The combined conductivities of the intrinsic and extraneous ions vary as a function of pH and
are the basis for the conductivity specifications described in the
Stage 3
—
pH and Conductivity
Requirements
table and used when performing
Stage 3
of the test method. Two preliminary
stages are included in the test method.



If the test conditions and conductivity limits are met at either of these preliminary stages, the
water meets the requirements of this test. Proceeding to the third stage of the test in these
circumstances is unnecessary. Only in the event of failure at the final test stage is the sample
judged noncompliant with the requirements of the test.

如果检测条件和电导率限度符合前一阶段，则水符合本检测标准，不需要一直进行 至第三阶段。
一个样品只有在做到最后一个阶段仍不符合要求时才认为是不符合本测试标准。

Procedure
程序

S
TAGE
1
第一阶段

Stage 1
is intended for online measurement or may be performed offline in a suitable
container.

第一阶段是在线检测或在适当容器内的离线检测

1. Determine the temperature of the water and the conductivity of the water using a
nontemperaturecompensated conductivity reading.

1.
测定水温，读取无温度补偿的电导率值。

2. Using the
Stage 1
—
Temperature and Conductivity Requirements
table, find the temperature
value that is not greater than the measured temperature, i.e., the next lower temperature. The
corresponding conductivity value on this table is the limit. [N
OTE
—
Do not interpolate. ]

2.
将电导率读数与第一阶段—温度和电导率要求 表进行比较，
找出小于等于实测温度的温度值，
即下一个较低温度，表中所对应的电导率值为其 限度【注：不要进行插入法计算】
。

3. If the measured conductivity is not greater than the table value, the water meets the
requirements of the test for conductivity. If the conductivity is higher than the table value,
proceed with
Stage 2.

3.
如果所测得的电导率不大于表中要求值，则水样符合电导率要求。如果比 表中示值更高，则
进入第二阶段测试。

Stage 1
—
Temperature and Conductivity Requirements

第一阶段
---
温度和电导率要求