Radiometer ABL-700, ABL-800 Reference manual

ABL700 series reference manual

ABL700

series

reference

manual

Note to the users of the EML105, ABL5xx, ABL SYSTEM 6xx,

ABL7xx Series, ABL800 FLEX and ABL800 BASIC analyzers

Introduction

Brief overview of the change

This note to users outlines a change in the operator’s and reference manual for your EML105, ABL5xx, ABL SYSTEM 6xx, ABL7xx Series, and/or ABL800 FLEX and ABL800 BASIC analyzer.

Operator’s manual:

Limitations of use and known interfering substances:

CAUTION - Known interfering substances

Substance Interference

–

ClO

(drugs) For ClO

– ,

interference on cCa2+ (1.25 mmol/L

level) has been detected:

(1.25 mmol/L level): 0.20*.

cCa

Technical documentation

Instructions to user

* Depending on the pH level

Reference manual:

Change/Description

Interference on

For ClO detected. The interference results for ClO

– ,

interference on cCa2+ (1.25 mmol/L level) has been

–

are as follows:

Interference on…

Substance Test Conc. cK+

(4 mmol/L

level)

–

ClO

1.5 mmol/L - -

* Depending on the pH level A "-" indicates that interference has not been measured on the respective parameter.

cNa

(150 mmol/L

level)

(1.25 mmol/L

cCa

level)

0.20*

(110 mmol/L

cCl

level)



8-30

The manual will be updated with the above information as part of the next manual update.

Please place this note to the users in the binder of your manual.

Note to users of the ABL700 Series analyzers

Mandatory upgrade of the manual

Cleaning solution with cleaning additive installation

The manuals for the ABL700 Series analyzers must be upgraded with regard to the information on cleaning solution.

The procedure for adding cleaning additive has been changed for the abovementioned analyzers and from now on the following instructions must be followed:

Remove the foil from the DosiCapZip and unscrew it (Figs. 1+2).

Turn the DosiCapZip upside down and screw it onto the container again (Figs. 3+4).

TCAUTIONT: TIf the contents of the DosiCapZip or the container have

been spilt by accident, both the container and the DosiCapZip should be

discarded to prevent incorrect concentrations in the solution.

Invert the container at least 20 times to dissolve the additive (Fig. 5).

Place the container horizontally so that the solution may enter the

DosiCapZip and leave it for 3 minutes (Fig. 6).

Invert the container again at least 20 times to fully dissolve the additive (Fig. 7).

Unscrew the lid from the new solution container.

Remove the used solution container by holding it on the sides and pulling.

Scan the barcode of the new solution, using the barcode reader.

Place the new solution container in position on the analyzer and push it firmly onto the connector as far as possible.

10.

For the ABL700 Series analyzers, sw. 3.836: Press Restart to restart the analyzer.

For the ABL700 Series analyzers, sw. 6.00: Press Restart and Accept to

restart the analyzer.

Cleaning solution with cleaning additive – general information

Cleaning Solution 175 mL 944-123 S7375

Use: For cleaning the measuring system of the ABL700 Series analyzers. Contains: Salts, buffer, anticoagulant, preservatives, surfactants and enzyme.

Safety Data Sheet may be obtained from your local distributor.

Item Code No. Type

Storage: At 2-10 °C. Stability in use: The Cleaning Solution with the Cleaning Additive is stable for 2

months in use.

Analyzer: Perform cleaning every 8th hour.

T CAUTION – Risk of personal injury

TDo not breathe dust (S22). Avoid contact with skin (S24). Irritating to eyes and

skin (R36/38). Wear suitable gloves (S37). May cause sensitization by inhalation and skin contact (R42/43). In case of accident or if you feel unwell, seek medical advice immediately (show the label where possible) (S45).

Texts no longer valid in the manuals

Due to new cleaning solutions, information about Cleaning solution S7370 and Cleaning additive S5370 is no longer valid.

Below is a list of the sections in the manual that must be ignored.

ABL700 Series reference manual:

Technical documentation

Instructions to user

Chapter 7: Solutions and gas mixtures: S7370 Cleaning Solution and

S5370 Cleaning additive:

Text no longer relevant.

See instruction about the new Cleaning Solution S7375 above instead.

Index: Cleaning Additive references no longer

relevant.

The manuals for the ABL700 Series analyzers will be updated with the above information when reprinted.

This update kit includes a note to the user with the changes and a new date of issue page of the manual. Please place the note to the user in the binder of the ABL700 Series reference manual and replace the date of issue page with the new corresponding page, then discard the old page.

Reference

ABL700 Series

1. Introduction

2. Electrodes

3. The Optical System

Contents

Manual

4. User-defined Corrections

5. Performance Characteristics

6. Parameters

7. Solutions

8. Interfacing Facilities

Index

Date of Issue

SYSTEM PERFORMANCE AND WARRANTY DISCLAIM

Radiometer cannot provide or verify instrument performance characteristics and accept warranty claims or product liability claims if the recommended procedures are not carried out, if accessories other than those recommended by Radiometer are used, or if instrument repairs are not carried out by authorized service representatives.

The instructions given in the Operator’s Manual for the ABL700 Series must be observed in order to ensure proper instrument performance, and to avoid electrical hazards.

TRADEMARKS

ABL™, BMS™, FLM™, CMT™, Deep Picture™, QUALICHECK™ and RADIOMETER™ are trademarks of Radiometer Medical ApS, Denmark.

ABL is registered in the USA. QUALICHECK is registered in the USA and in some other countries.

The contents of this document may not be reproduced in any form or communicated to any third party without the prior written consent of Radiometer Medical ApS.

While every effort is made to ensure the correctness of the information provided in this document Radiometer Medical ApS assumes no responsibility for errors or omissions which nevertheless may occur.

ABL700 Series Reference Manual Contents

1. Introduction .............................................................................................. 1-1

ABL700 Series Documentation .................................................................. 1-2

Warnings/Cautions and Notes .................................................................... 1-3

2. Electrodes.................................................................................................. 2-1

General Construction .................................................................................. 2-2

General Measuring Principles..................................................................... 2-3

Calibration .................................................................................................. 2-7

Electrode Measuring Time and Updatings ............................................... 2-14

Reference Electrode.................................................................................. 2-15

pH Electrode ............................................................................................. 2-16

pCO

Electrode ......................................................................................... 2-23

Electrode............................................................................................ 2-32

Electrolyte Electrodes ............................................................................... 2-42

Metabolite Electrodes ............................................................................... 2-54

References................................................................................................. 2-64

3. The Optical System ................................................................................... 3-1

Measuring Principle.................................................................................... 3-2

Correcting for Interferences........................................................................ 3-7

Calibration .................................................................................................. 3-9

Measurement and Corrections .................................................................. 3-10

References................................................................................................. 3-13

4. User-Defined Corrections ......................................................................... 4-1

General Information.................................................................................... 4-2

Correction Factors for Oximetry Parameters and Bilirubin........................ 4-4

Electrolyte and Metabolite Parameters ....................................................... 4-8

5. Performance Characteristics.................................................................... 5-1

General Information.................................................................................... 5-2

Definition of Terms and Test Conditions ................................................... 5-3

Reference Methods for the ABL700 Series ................................................ 5-8

ABL735/30/25/20/15/10/05 Performance Test Results - Macromodes.... 5-10

ABL735/30/25/20/15/10/05 Performance Test Results - Micromodes .... 5-19

ABL700 Performance Test Results .......................................................... 5-30

ABL735/30/25/20/15/10/05/00 Expired Air Mode .................................. 5-32

ABL735/30/25/20/15/10/05/00 Capillary - pH Only Mode ..................... 5-35

Contents ABL700 Series Reference Manual

ABL735/30 Performance Test Results - Bilirubin.................................... 5-36

Interference Tests...................................................................................... 5-42

References................................................................................................. 5-50

6. Parameters ................................................................................................. 6-1

General Information.................................................................................... 6-2

Acid-base Parameters.................................................................................. 6-6

Oximetry Parameters .................................................................................. 6-8

Oxygen Parameters ..................................................................................... 6-9

Bilirubin.................................................................................................... 6-13

Electrolyte Parameters .............................................................................. 6-14

Metabolite Parameters .............................................................................. 6-15

Units and Ranges for Measured Parameters ............................................. 6-16

Units and Ranges for Input Parameters .................................................... 6-19

Units and Ranges for Derived Parameters ................................................ 6-20

List of Equations....................................................................................... 6-25

Oxyhemoglobin Dissociation Curve (ODC)............................................. 6-41

Conversion of Units.................................................................................. 6-46

Default Values .......................................................................................... 6-48

Altitude Correction ................................................................................... 6-49

References................................................................................................. 6-50

7. Solutions and Gas Mixtures ..................................................................... 7-1

General Information.................................................................................... 7-2

S1720 and S1730 Calibration Solutions ..................................................... 7-3

S4970 Rinse Solution ................................................................................. 7-4

S7370 Cleaning Solution and S5370 Cleaning Additive............................ 7-5

S7770 tHb Calibration Solution.................................................................. 7-6

Gas Mixtures (Gas 1 and Gas 2) ................................................................. 7-7

Electrolyte Solutions................................................................................... 7-8

S5362 Hypochlorite Solution ..................................................................... 7-9

Certificates of Traceability ....................................................................... 7-10

8. Interfacing Facilities ................................................................................. 8-1

Connecting a Mouse ................................................................................... 8-2

Connecting an Alphanumeric Keyboard..................................................... 8-3

Connecting the Bar Code Reader................................................................ 8-4

Connecting a Network ................................................................................ 8-6

Index

Date of Issue

ABL700 Series Reference Manual 1. Introduction

1. Introduction

Overview

This section gives an introduction to the documentation that accompanies your ABL700 Series analyzer. It describes how this particular manual is organized and explains the different notices that appear in it.

Contents

This chapter contains the following topics.

ABL700 Series Documentation ....................................................................... 1-2

Warnings/Cautions and Notes.......................................................................... 1-3

1-1

1. Introduction ABL700 Series Reference Manual

ABL700 Series Documentation

ABL700 Series Analyzers

Documentation

The documentation that accompanies the ABL700 Series analyzers covers the series in general - each possible electrode combination is not considered individually.

The table below describes the documentation that comes with each analyzer.

Documentation Description

Design of Manual

The Operator’s Manual

Contains all the information required for everyday operation of the analyzer.

Describes the functions of the analyzer and how to set it up according to customer needs and requirements.

Explains error messages and gives troubleshooting procedures.

Contains ordering information

The Reference Manual

Gives detailed information about the operating principles of the analyzer.

Describes the measuring and calibrating principles.

Lists all the parameters.

Gives the equations from which the derived parameters are calculated.

Gives information about how the performance of the analyzer is tested.

On-line Help Summarizes the information found in the Operator’s

Manual.

Gives hands-on help at the analyzer.

Depending on the set up of your analyzer, the entire Reference Manual may not be applicable to it. However the manual is designed in such a way that it is easy to disregard or remove the sections that are not relevant to your instrument.

1-2

ABL700 Series Reference Manual 1. Introduction

Warnings/Cautions and Notes

Definitions

List of

WARNING/ CAUTION

Notices

The following table indicates the type of information given in warnings, cautions, and notes:

Notice Definition

WARNING

Warnings alert users to potentially serious outcomes to

selves or to the patient (such as death, injury, or serious

them adverse events).

PRECAUTION

Precautions alert users to exercise the special care necessary for safe and effective use of the device. They

may include actions to be taken to avoid effects situations on patients or users that may not be potentially life threatening or result in serious injury , but about which the user should be aware. Precautions may also alert the user to adverse effects on the device caused by use or misuse, and the care required to avoid such effects.

NOTE

Notes give practical information.

All WARNING/CAUTION notices that appear in this manual, are listed below.

S5370 Cleaning Additive: May cause sensitization by inhalation and skin

•

contact). Do

not breathe dust. Avoid contact with skin. Wear suitable gloves.

In case of accident or if you feel unwell, seek medical advice immediately (show the label where possible).

Gas Mixtures: Not for drug use. High pressure gas. Do not puncture. Do not

•

store near heat or open flame - exposure to temperatures above 52 C

(125 F) may cause contents to vent or cause bursting. Not for inhalation. Avoid

breathing gas - mixtures containing carbon dioxide

can increase respiration and heart rate. Gas mixtures containing less than

19.5 % oxygen can cause rapid suffocation. Store with adequate ventilation. Avoid contact with oil and grease. Only use with equipment rated for cylinder pressure. Use in accordance with Safety Data Sheet.

1-3

Introduction

Contents

2. Electrodes

This chapter describes the construction, measuring principle and calibration process for each of the electrodes in the ABL700 Series analyzers.

General sections covering the background theory used for measurements and calibrations are also presented here.

This chapter contains the following topics.

General Construction ....................................................................................... 2-2

General Measuring Principles .......................................................................... 2-3

Calibration........................................................................................................ 2-7

Electrode Measuring Time and Updatings....................................................... 2-14

Reference Electrode ......................................................................................... 2-15

pH Electrode .................................................................................................... 2-16

Electrode................................................................................................. 2-24

pCO

Electrode ................................................................................................... 2-33

Electrolyte Electrodes ...................................................................................... 2-43

Metabolite Electrodes....................................................................................... 2-55

References........................................................................................................ 2-65

2. Electrodes ABL700 Series Reference Manual

General Construction

An Electrode

In this manual and other Radiometer literature, the term electrode refers to the whole sensor unit, i.e. both the electrode and the electrode jacket. Radiometer electrodes are cordless, thereby limiting the level of noise picked up during the measuring process. The electrical signals from the electrodes are amplified by preamplifiers placed in each module.

A generalized diagram of a Radiometer electrode is given below.

Electrolyte solution

Electrical contact

Color-coded ring

Electrode jacket

Membrane

The main electrode parts are described below.

Part Description

Electrical contact Provides electrical contact between the electrode and the

analyzer.

Color-coded ring Marks each electrode for easy recognition.

Electrode jacket Holds the electrolyte solution and membrane, and protects

the electrode.

Membrane A thin sheet-like material to separate the sample from the

electrode, that differentiates between the substances allowed to pass through it towards the electrode.

2-2

Electrolyte solution

A conducting solution to provide an electric contact between the electrode and the sample (also known as a salt-bridge solution).

More specific descriptions of the electrodes are found under the appropriate electrode titles in this chapter.

ABL700 Series Reference Manual 2. Electrodes

General Measuring Principles

Introduction

There are two different measuring principles employed for electrodes in the ABL700 Series.

• Potentiometry: The potential of an electrode chain is recorded using a

voltmeter, and related to the concentration of the sample (the Nernst equation).

• Amperometry: The magnitude of an electrical current flowing through an

electrode chain, which is in turn proportional to the concentration of the substance being oxidized or reduced at an electrode in the chain.

These two measuring principles are described in detail on the following pages.

Potentiometric Method

An electrode chain describes an electrical circuit consisting of a sample, electrode, reference electrode, voltmeter, membranes, and electrolyte solutions.

Voltmeter

Reference

electrode

Electrolyte

solution

Membrane

Sample

Electrolyte

solution

Membrane

Electrode

Every element in the electrode chain contributes a voltage to the total potential drop through the chain. Thus:

• When immersed in the appropriate electrolyte solution, both electrodes have

separate potentials.

• The membrane junctions between the sample and electrolyte solutions also have

separate potentials.

The complete electrode chain potential therefore, is the sum of these separate potentials and is the quantity measured by the voltmeter.

E = E – E

total sample Ref

where the final unknown potential (E electrode chain potential (E

) and the reference potential (E

total

) can be calculated knowing the total

sample

that is constant

Ref

between two subsequent calibrations).

Continued on next page

2-3

2. Electrodes ABL700 Series Reference Manual

General Measuring Principles, Continued

Potentiometric Method

(continued)

Having measured the unknown potential (E applied to determine the activity (a

) of the species under study:

sample

where:

R =

T n

F =

= standard electrode potential

gas constant (8.3143 JK

= absolute temperature (310 K (37

= charge on the ion

Faraday constant (96487 C mol

= activity of

−1

mol−1)

The Nernst equation is rearranged to express the activity as a function of the potential

. Having measured E

sample

the activity can be calculated since all

sample

other quantities are already known. Finally the analyzer converts activity to concentration.

), the Nernst equation is then

sample

23R

log

−1

C ))

)

Strictly speaking, in potentiometry the potential of an electrode chain or the magnitude of current flowing through an electrical chain is related to the activity of a substance, and not its concentration.

Activity expresses the ‘effective concentration’ of a species, taking non-ideality of the medium into account.

Activity and concentration are related by the following equation:

= γ c

where:

= the activity of the species x

= the activity coefficient of species x under the measurement conditions

(for ideal systems

= the concentration of species x (mmol/L)

γ = 1)

NOTE:

To be exact, activity is related to the molality of species x, i.e., the number of mmoles per kg of solvent. However molality is converted to concentration (molarity).

ABL700 Series analyzers automatically convert activities into concentrations

[1].

The term concentration is therefore used in explanations of the measuring principles for each of the electrodes further on in this chapter.

2-4

The potentiometric measuring principle is applied in the pH,

pCO

electrodes. It is slightly different for the

electrode, however, since the Nernst

equation is not directly applied.

pCO

, and electrolyte

Continued on next page

ABL700 Series Reference Manual 2. Electrodes

General Measuring Principles, Continued

Amperometric Method

The electrode chain in amperometric measurements consists of the sample, the two electrodes (anode and cathode), an amperemeter, a voltage source, the membranes, and the electrolyte solutions.

Applied voltage

Anode Cathode

Electrolyte solution

Sample

mperemeter

Membrane

Part Function

Cathode Negative electrode where a reduction reaction occurs and

electrons are consumed.

Anode Positive electrode where an oxidation reaction occurs and

electrons are released.

Electrolyte

Provides electrical contact between the anode and cathode.

solution

Membrane Allows the appropriate molecules to pass through from the

sample.

Sample Contacts the membrane.

Applied voltage Applies the necessary potential for the reduction or oxidation

reaction under study.

Amperemeter Measures the current flowing through the circuit.

To simplify the description of the measuring process in an amperometric electrode, we make the following assumptions:

• there is a species A in the sample which is reduced at the cathode to A

• there is a species X in the electrolyte which is oxidized at the anode to X

−

Continued on next page

2-5

2. Electrodes ABL700 Series Reference Manual

General Measuring Principles, Continued

Amperometric Method (continued)

The membrane is selective to the species A, allowing no other species but it to pass

through from the sample into the electrolyte solution.

As an appropriate potential is applied across the electrodes, the species

A is

reduced at the cathode according to the following reaction:

A + e

−

→ A

−

The reduction of A produces a flow of electrons, i.e. an electrical current.

To complete the electrical circuit an oxidation reaction where electrons are released is necessary. Therefore species

X is oxidized according to the following

reaction:

→ X

+ e

−

The magnitude of the current flowing through the circuit is proportional to the concentration of the species being reduced, in this case species thereby automatically calculates the concentration of

A in the sample.

A. The analyzer

The amperometric measuring principle is applied in the electrodes.

, glucose, and lactate

2-6

ABL700 Series Reference Manual 2. Electrodes

−

Calibration

Actual Electrode Condition

Calibration Line

The electrodes are active elements and must be calibrated regularly as the signals from the electrodes change with, e.g. age or deposits on the membrane.

Calibration relates the electrode signals during the calibration sequence to the values of the calibrating solutions and must be performed at regular intervals so that the accuracy can be constantly refined after inevitable minor changes in the electrodes’ behavior.

Actual electrode condition is described by status/zero point and sensitivity and compared with theoretical conditions for an "ideal" electrode. In addition to status and sensitivity, an electrode condition is described by drift.

The calibration line expresses the relationship between the potential (or current) measured at an electrode, and the concentration of the species specific to the electrode. The calibration line forms the basis of the scale used by the analyzer to convert electrode chain potentials to concentrations. Each electrode has a different calibration line.

The pH electrode is used as an example to illustrate how this line is derived from two calibration solutions of known pH.

• Cal 1 solution has a pH of 7.398 that gives potential reading of −100 mV.

• Cal 2 solution has a pH of 6.802 that gives a potential reading of −64 mV.

These two values are plotted on a graph.

The relationship between potential and pH is linear so a line can be drawn between the two points, as shown below:

Measured potential (mV)

Calibration line

7.398

pH of Cal 1 sol.

100

6.802

pH of Cal 2 sol.

7.346

pH of sample

The calibration line now forms the scale used to convert the potential measured at the pH electrode during sample analysis to an actual pH value.

Continued on next page

2-7

2. Electrodes ABL700 Series Reference Manual

Calibration, Continued

Calibration Line (continued)

A blood sample gives a potential reading of -97 mV at the pH electrode. Reading off from the calibration line shown below, this potential corresponds to a pH of

7.346.

Measured potential (mV)

−

Theoretical Calibration Line

Calibration line

7.398

pH of Cal 1 sol.

−

100

6.802

pH of Cal 2 sol.

7.346

pH of sample

The calibration line is updated at every calibration. Drift describes the variation in the calibration line between consecutive calibrations.

The theoretical calibration line is the relationship between potential and concentration in a potentiometric measurement, or the relationship between current and concentration in an amperemetric measurement.

In the ABL700 Series the theoretical calibration line for pH is defined by the following two points:

pH Electrode potential

(vs. Ref. potential)

6.800

7.400

Measured potential (mV)

−75.5 mV

−112.4 mV

2-8

−75.5

−112.4

6.8

7.4

The position and slope of the calibration line compared to the theoretical calibration line are described by the status and sensitivity respectively.

Continued on next page

ABL700 Series Reference Manual 2. Electrodes

Calibration, Continued

Sensitivity

Electrode sensitivity expresses how a real electrode measures compared with the specified values of the calibration material; it illustrates the slope of the calibration line derived from a 2-point calibration as a percentage (or fraction) of the slope of the theoretical calibration line, as determined by the Nernst equation of the ion in question.

Calculating the sensitivity is a way of monitoring the deviation of the electrode sensitivity from the theoretical value.

Calculation of the sensitivity is shown, using the pH electrode as an example.

A theoretical calibration line for the pH electrode with a slope of

−61.5 mV/pH is

drawn:

Measured potential (mV)

75.5

−

Theoretical calibration line

112.4

−

6.8

7.4

The calibration line from a 2-point calibration is superimposed on the same graph:

Measured potential (mV)

−

75.5

2-point calibration line Slope = −58.4 mV/pH Sensitivity = 95 %

Theoretical calibration line

112.4

−

6.8

Slope= −61.5 mV/pH Sensitivity = 100 %

7.4

The sensitivity of the electrode is calculated as the ratio between the slope of the 2point calibration line and that of the theoretical line, expressed as a percentage or fraction.

If the theoretical calibration line is assumed to have a sensitivity of 100 %, the 2point calibration line shown in the example will have a sensitivity of approximately 95 %.

Continued on next page

2-9

2. Electrodes ABL700 Series Reference Manual

Calibration, Continued

Sensitivity (continued)

Status

The sensitivity limits for the calibration are set for each electrode. If the sensitivity of any electrode falls outside the allowed limits, the message

out of range

appears in the Calibration Messages, with the particular electrode

Calibration Sensitivity

specified.

The electrode status is a measure of zero point of a complete electrode chain. Status of a real electrode reflects deviations from the conditions of a theoretical electrode, and define the position of the calibration line.

Calculating the status value of an electrode is a way of monitoring the position of the calibration line despite the fact that only a 1-point calibration has been carried out. The calculation of the status is shown, using the pH electrode as an example.

A calibration line with the same slope as the theoretical calibration line (

−61.5

mV/pH) is drawn through this point. This theoretical calibration line is used since no 2-point calibration is performed which would otherwise give an actual calibration line.

Measured potential (mV)

Theoretical calibration line with a slope = −61.5 mV/pH drawn through

Cal 1

A pH of 7.400, the nominal pH of Calibration Solution 1 (pH corresponding potential (

) is read off the theoretical calibration line that

Cal 1 nom

the point from a 1-point calibration.

Cal 1

) is chosen. Its

Cal 1 nom

was drawn through the 1-point calibration point.

Measured potential (mV)

Theoretical calibration line for the theoretical pH electrode with known potential of −112.4 mV at a pH =

7.400.

2-10

Cal 1 nom(theo)

E=−112.4 mV

Cal 1 nom

Cal 1

∆pH

∆

Theoretical calibration line drawn through the 1point calibrat ion point.

Status

Cal 1 nom

(7.400)

Cal 1

Continued on next page

ABL700 Series Reference Manual 2. Electrodes

−

Calibration, Continued

Status (continued)

A line from pH corresponding potential (

is extrapolated up to the theoretical calibration line, and the

Cal 1 nom

Cal 1 nom(theo)

) read off the theoretical calibration line.

Calibration Materials

The difference between

Cal 1 nom

and E

Cal 1 nom(theo)

which corresponds to ∆E on the

graph, represents the potential that should theoretically be obtained for a solution with pH = 7.400. This potential difference (

∆E) thus describes the deviation of the

actual pH reference electrode system from a theoretical electrode system. Similarly

∆pH describes the deviation in pH values that would be produced

between measurements with an actual electrode system and measurements with a theoretical electrode system.

The status of the pH electrode, pH(Status), is then calculated as:

pH(Status) = 7.4 +

Cal 1 nom Cal 1 nom(theo)

61.5

The status limits of the calibration are set for each electrode. If the status for any electrode falls outside the allowed limits, the message

appears in the Calibration Messages, with the particular electrode specified.

limits

Calibration status out of

The following calibration materials are used:

Calibration Material Used for...

Calibration Solutions 1 and 2: the exact composition of the calibration solutions is given in the bar code on the bottle label, which can be read into the analyzer using the

Calibration of the pH, and electrolyte electrodes

bar code reader, or entered manually via the keyboard.

Calibration Solution 1: Calibration of the

metabolite electrodes and optical system

Gas 1 and Gas 2: each gas has a precise composition essential for determining the accuracy of the analyzer in

each pCO

and pO

measurement.

Calibration of the

pCO

and pO

electrodes

tHb Calibration Solution: Calibration of the

optical system

The Chemical Reference Laboratory at Radiometer is responsible for the accuracy of the calibrating solutions and gases.

Traceability certificates for individual solutions are presented in Chapter 7 of this

manual.

Continued on next page

2-11

2. Electrodes ABL700 Series Reference Manual

Calibration, Continued

Drift

Drift is defined as the difference measured by the electrodes during last and previous calibrations, and is a measure of the electrode stability.

Drift 1 is obtained on Calibration Solution 1 and/or Gas 1 and is calculated as

follows, using the pH electrode as an example:

Measured potential

Calibration line from last 2-point calibration

(mV)

1-point calibration

Drift 1 value

1-point calibration

2-point calibration

Calibration Solution 2

Calibration Solution 1

Drift 2 is obtained after 2-point calibration. The pH electrode is used as an

example and the calibration schedule is set so that each 2-point calibration is separated by two 1-point calibrations.

Measured potential (mV)

Drift 2

Calibration line from 2

Slope of 1

Calibration line from 1

2-point calibration

2-point calibration line

2-point calibration

1-point calibration

Calibration Solution 2

Calibration Solution 1

Drift tolerances express the extent to which drift values for an electrode can fluctuate before the electrode is deemed unstable and thus incapable of providing reliable calibrations.

The drift tolerances for each electrode are set in the analyzer’s Setup programs. Radiometer recommends the use of the default drift tolerances, as too narrow drift tolerances will cause electrode drift errors even for normal electrode fluctuations. If the drift tolerances are too wide, significant measurement errors will result without warning.

Continued on next page

2-12

ABL700 Series Reference Manual 2. Electrodes

Calibration, Continued

Drift (continued)

If the drift values for any electrode fall outside the drift tolerances, the message

Calibration drift out of range appears in the Calibration Messages, with the

particular electrode specified.

No drift values are reported for startup calibrations as there are no previous calibrations available for comparison.

2-13

2. Electrodes ABL700 Series Reference Manual

Electrode Measuring Time and Updatings

Measuring Time

Updatings

In the ABL700 Series analyzers the measuring time of the electrode is independent of the electrode type. Electrode signals are registered at 0.982 second intervals during both calibrations and measurements. The registration of each electrode signal begins after the samples, calibration solutions, and calibration gases are in position in the measuring modules.

The duration of each calibration is predetermined, as is the number of updatings of the electrodes’ signals.

In general, the updatings from an electrode response are numbered from 1 to upd last, where updating number 1 is the first updating and upd last is the last. The

diagram below schematically illustrates the electrode response that is calculated on uncorrected electrode updating values in the ABL700 Series.

Signal

Upd 1 Upd last

Updatings

2-14

+ 204 hidden pages

Radiometer ABL-700, ABL-800 Reference manual

Specifications and Main Features

Frequently Asked Questions

User Manual

Contents

1. Introduction

ABL700 Series Documentation

Warnings/Cautions and Notes

2. Electrodes

General Construction

General Measuring Principles

Calibration

Electrode Measuring Time and Updatings