background image

3.6 pH Calibration Using Buffers

When performing calibrations two buffer solutions are required, a pH7 and either a pH4 or 10,
dependent on the type of measurement being performed, i.e; acidic (pH4) or alkaline (pH10).
Buffer solutions should be carefully prepared as per the Manufacturers instructions.

Calibration - with Manual Temperature Compensation

1.

Select 

°C

 on the

 Function

 switch. Measure the temperature of the buffer solutions. The

instrument display should then be set to the buffer solution temperature measured, using the

Slope/Manual Temp 

control.

2.

Select 

pH Cal 

on the 

Function

 switch. Immerse the electrode(s) in the pH7 buffer solution.

Allow sufficient time for the pH reading to stabilise. Set the display to the correct value of the
buffer (at the temperature measured in 1.) using the

 Buffer

 control.

3.

Rinse the electrode(s) in deionised water.

4.

Immerse the electrode(s) in pH 4 or 10 buffer, depending on the type of sample to be tested.
Allow sufficient time for the pH reading to stabilise. Set the display to read the correct value of
the buffer (at the temperature measured in 1.) using the 

Slope/Manual Temp

 control.

Repeat steps 2-4 until no further adjustments are necessary. Care should be taken when
making adjustments as the controls are interdependent.

5.

Rinse the electrode(s) in deionised water.

6.

Select 

pH

 on the 

Function

 switch. When this position is selected the calibration settings are

locked (no further adjustment can be made to the buffer and slope values until the 

pH Cal

position is re-selected on the

 Function 

switch).

7.

If the temperature of the unknown solution differs from the buffer, the Slope/Manual Temp
Control should be used to set the instrument display to the temperature of the unknown
solution.

8.

Immerse the electrode(s) in the unknown solution. The display will indicate the pH value of the
solution.

Calibration - with Automatic Temperature Compensation (ATC)

1.

Select 

pH Ca

l on the 

Function

 switch. Immerse the electrode(s) and ATC probe in the pH7

buffer solution. Allow sufficient time for the pH reading to stabilise. Set the display to read the
temperature compensated value of the buffer solution using the Buffer control.

2.

Rinse the electrode(s) and ATC probe in deionised water.

3.

Immerse the electrode(s) and ATC probe in the second buffer solution. Allow sufficient time
for the pH reading to stabilise. Set the display to read the temperature compensated value of
the buffer solution using the Slope/Manual Temp control.
Repeat until no further adjustments are necessary. Care should be taken when making
adjustments as the controls are interdependent.

4.

Rinse the electrode(s) and ATC probe in deionised water.

350 550/REV A/03-03

8

Summary of Contents for 3505

Page 1: ...350 550 REV A 03 03 Model 3505 pH mV Temperature Meter Operating Manual...

Page 2: ...and service personnel employ a safe system of work in addition to the detailed instructions specified in this manual 3 References should always be made to the Health Safety data supplied with any chem...

Page 3: ...rement 3 1 pH Measurement 3 2 Preparation of Buffer Solution 3 3 Solution Temperature Values 3 4 Good Practice Guidelines 3 5 pH Calibration Using Buffers 3 6 Performing Measurements 3 7 Section 4 Mai...

Page 4: ...3505 has a liquid crystal display and is battery operated The use of an optional power supply permits the unit to be operated from the a c mains supply 1 2 Instrument Specifications Range Resolution 2...

Page 5: ...ing plug 009 146 7 Battery PP3 8 Condensed operating instructions 350 551 9 Instruction manual 350 550 Any shortages or damage should be reported immediately to the Manufacturer or your local Distribu...

Page 6: ...lance out the electrode offset between the pH measurement cell and reference This should be set with the electrode immersed in pH7 buffer This control adjusts the electrode effect between 60mV to 60mV...

Page 7: ...ch allows combination pH or redox electrodes to be used 3 Temp Socket 8 pin mini DIN socket This allows the Automatic Temperature Compensation ATC probe 027 500 to be connected 4 Analog Out 2 x 4mm so...

Page 8: ...ies These can be used as a guide to the pH colour level but can be limited in accuracy and difficult to interpret correctly in murky or coloured samples For greater accuracy the use of a high impedanc...

Page 9: ...te and repeatable results it is essential to follow the manufacturers instructions carefully 3 4 Solution Temperature Values The value of all buffer solutions varies with solution temperature For accu...

Page 10: ...gel filled electrodes are not refillable 5 DO NOT touch the sensitive glass pH membrane or reference junction during use Excess droplets of solution may be removed by gently blotting with filter paper...

Page 11: ...he controls are interdependent 5 Rinse the electrode s in deionised water 6 Select pH on the Function switch When this position is selected the calibration settings are locked no further adjustment ca...

Page 12: ...socket on the rear panel b Select C on the Function switch The display will show ATC probe temperature directly in C 3 Temperature Measurement Manual a If Manual temperature compensation is being use...

Page 13: ...nd in the solution until clean Rinse and repeat as necessary Electrodes which have been allowed to dry out should be soaked overnight in warm distilled water Table of Cleaning Agents for Glass Electro...

Page 14: ...died combination 12mm diameter For liquids 924 005 General purpose glass bodied combination 12mm diameter For liquids For a complete listing of all available electrodes please contact your local distr...

Page 15: ...ted thermometer Slope Buffer controls 3505 incorrectly set Set Dial to pH Cal not working Battery symbol is displayed Battery running out Less than 8hrs lifetime left replace battery If the above does...

Page 16: ...ture input check Remove the temperature probe and apply a 10Kohm resistor across the pins of the temp input as described in fig 7 2 1 Fig 6 2 1 Temperature input with connection detail 350 550 REV A 0...

Page 17: ...dard EN 50082 1 1992 Electromagnetic compatibility Generic immunity standard Performance criterion B EN 61010 1 1993 Safety requirements for electrical equipment for measurement control and laboratory...

Page 18: ...g the details below UK Office Keison Products P O Box 2124 Chelmsford Essex CM1 3UP England Tel 44 0 330 088 0560 Fax 44 0 1245 808399 Email sales keison co uk Please note Product designs and specific...

Reviews: