Denville Scientific CO7500 User manual

Denville®CO7500 Colorimeter
User Manual

Declaration of Conformity
This is to certify that the CO 7500 Colorimeter
manufactured by Biochrom Ltd. conform to the requirements of the following
Directives-: 73/23/EEC & 89/336/EEC
Standards to which conformity is declared
EN 61 010-1: 2001
Safety requirements for electrical equipment for measurement, control and
laboratory use.
EN 61326: 1998
Electrical equipment for measurement, control and laboratory use –EMC
requirements
Signed: Dated: 24th March 2003
David Parr
Managing Director
Biochrom Ltd
Postal address Telephone Telefax
Biochrom Ltd [phone] [phone]
22 Cambridge Science Park
Milton Road e mail: [email protected] website: http://www.biochrom.co.uk
Cambridge CB4 0FJ
England
Registered in England No: 3526954
Registered Office: 22 Cambridge Science Park, Milton Road, Cambridge CB4 0FJ, England.
Biochrom Ltd
Certificate No. 890333

CONTENTS
Unpacking, Positioning and Installation 1
OPERATION 2
Introduction 2
Using the Instrument 3
Making an Absorbance or %T measurement 4
Making a kinetics measurement 4
TROUBLE SHOOTING NOTES 5
ACCESSORIES, CONSUMABLES AND SPARES 6
OUTPUT OF RESULTS 6
Use with serial printer 6
Use with PC 6
Use with chart recorder 6
MAINTENANCE 7
General maintenance 7
Changing a filter 7
Replacing the light bulb 8
SPECIFICATION AND WARRANTY 9

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Issue 02 - 12/2003 CO 7500, English 1
Unpacking, Positioning and Installation
Ensure your proposed installation site conforms to the environmental conditions
for safe operation:
Indoor use only
Temperature 5°C to 35°C
Maximum relative humidity of 80 % up to 31°C decreasing linearly to 50 %
at 40°C
If this equipment is used in a manner not specified or in environmental conditions
not appropriate for safe operation, the protection provided by the equipment may be
impaired and instrument warranty withdrawn.
The instrument is powered by mains electricity using the supplied power-
adapter. Using the instrument with the mains adapter will automatically
recharge the internal rechargeable battery (mains/battery version only).
The battery will last approx. 1 month when fully charged with normal use.
A full battery recharge will take approx. 12 hours (overnight).

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Issue 02 - 12/2003 CO 7500, English 2
OPERATION
Introduction
Your colorimeter is a small, robust, easy to use instrument that has been designed
with both the student user and “field” user in mind. It is ideal for teaching the
principles of science and analysis in sixth form colleges and technical schools, as
well as being rugged enough for measurements in, for example, remote location
health clinics where simple diagnostic tests need to be made.
The instrument measures in absorbance and % transmission mode as well as in
simple kinetics, enabling changes in absorbance over time and reaction rates to be
determined. It can be used in the 400 –700 nm wavelength range as it has an
integral, colour coded rotating wheel containing filters at 440, 470, 490, 520, 550,
580, 590 and 680nm. These are made from coloured gelatin and are encased in
glass, enabling the instrument to be used in “tropical” conditions. A filter is selected
by moving the wheel until the required wavelength is displayed in the window
above the cell compartment.
The instrument produces stable white light that is directed through the reference and
sample solutions in turn to a detector after being filtered to a single colour. This
colour is normally chosen to be complimentary (that which is most absorbed) to the
test solution. The amount of energy passing through the reference is deemed
equivalent to 100% transmission and is compared with that through the absorbing
sample, measured as T% (normally 0< T< 100).
Successful measurement of concentration is dependent on arranging the chemistry
and conditions to get the best agreement with the Beer/Lambert Law. To make full
use of the instrument’s excellent performance, it is recommended to arrange the
chemistry and dilutions to give Absorbance readings in the range 0.2 - 1.2A. Below
0.2A the relative concentration accuracy is reduced, whilst Absorbance readings
above 1.2A imply concentrations of high molar strength that do not obey
Beer/Lambert's Law so well. In addition small photometric errors become
increasingly important and the effect of stray light will increase.
If it is not possible to stay within these bounds it may be desirable to make
calibration curves for known concentrations and their measured Absorbances. As
colorimeter measurements are comparative it is essential that only the solutions
themselves change. This product contains a fully stabilised light source and
electronics with a fixed light path.
The instrument can be linked via a serial lead to either a serial printer for hardcopy
output or to a PC for download of results to spreadsheet. It has an analogue output,
and can also be connected to a chart recorder to output absorbance time data when in
kinetics mode.

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Issue 02 - 12/2003 CO 7500, English 3
Using the Instrument
Keypad
on/off
On / off button
R
to set reference to 0.000 OD at 600nm on a reference
T
to make a measurement
to measure kinetics
Abs/%T
To select between absorbance or %Transmission
Wavelength indicator
Display
There is a battery indicator
Note that the light beam shines from front to back through the cell chamber; ensure
the cell is inserted in the correct alignment.
The following table indicates the absolute minimum volume necessary for the
correct function of the unit. The use of disposable plastic cuvettes is recommended.
Cuvette/Tube
Min Volume
(ml)
Part number
Minimum Depth (approx) from
base of cuvette to meniscus (mm)
Macro Cuvette
(max fill volume 4.5ml)
1.0ml
80-3000-60
14mm
Semi-micro
(max fill volume 1.4ml)
0.5ml
80-3000-76
13mm
10mm diameter tube
0.9ml
-
16mm
12mm diameter tube
1.1ml
-
15mm
16mm diameter tube
2.2ml
-
15mm

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Issue 02 - 12/2003 CO 7500, English 4
Making an Absorbance or %T measurement
1. Switch the instrument on by pressing the ON/OFF button.
2. Select the required wavelength by turning the thumbwheel at the side of the
instrument. The wavelength selected is displayed in the window above the
cuvette compartment. Note: Two of the locations are empty.
3. Select Abs or %T mode
4. Place a reference into the cuvette compartment and press and release the R
(reference) button. The display will show 0.00 Abs or 100%T.
5. Remove the reference sample and replace with the sample solution in a cuvette
or tube.
6. Press and release the T(test) button. The result is displayed in absorbance or
%Transmission units
Multiple samples can be compared with the same reference by placing different
samples in the cuvette chamber and making measurements for each one. It is
recommended to re-reference with the reference solution every 10 to 15 minutes to
avoid any slow instrument drift. If in doubt, always re-reference.
Note: At high Absorbances the time taken to take a measurement will be longer (up
to 10 seconds) as the light levels are proportionally lower.
Making a kinetics measurement
1. The kinetics mode provides a continuous readout of changes in absorbance of a
sample.
2. Press and release the (kinetics) button.
3. Select Abs or %T mode
4. Place a reference into the cuvette compartment and press and release the R
(reference) button. The display will show 0.00 Abs or 100%T.
5. Remove the reference sample and replace with the sample solution in a cuvette
or tube.
6. Press and release the T(test) button. The lamp will remain on, the lamp
indicator will flash on the display, readings will be taken every 1-2 seconds and
the display will then show the changes in optical density (Abs or %T) over time.
The results are also output via both the RS232 and the analogue outputs.
7. To stop the readings repress the kinetics or Ttest button and the instrument will
revert to the flash mode of operation.

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Issue 02 - 12/2003 CO 7500, English 5
TROUBLE SHOOTING NOTES
ERROR INDICATION
SOLUTION
A flashing Absorbance
reading of 2.00 A is
obtained.
This indicates an Absorbance of more than 1.99 and
which is therefore out of range. The sample needs
to be diluted.
A negative reading is
obtained.
In normal measurements the test sample has a
positive Absorbance compared to that of the
Reference. Occasionally it can happen that the
chemistry has been arranged for a coloured
Reference and a less absorbing test solution, i.e.
one of negative Absorbance. The instrument will
respond correctly to negative absorbances down to
–0.30 A.
Negative readings will also be obtained if the
Reference and Test cuvettes are mixed up.
A flashing Absorbance
reading of –0.30 Abs is
obtained.
This indicates an Absorbance of less than –0.30
Abs and is therefore out of range. The sample
needs to be diluted.
Unexpected results are
obtained
Any bubbles in solution will produce considerable
error.
Check bulb is flashing
rEF is displayed when T is
pressed
The baseline has not been set. Replace the sample
with a blank or reference sample and press R. The
samples can then be tested.
No reading is obtained
when using the instrument is
being operated by battery.
Check that there is sufficient battery power
available. The battery power available is indicted
by the battery symbol at the bottom right hand
corner of the display.
Three bars in the battery indicates that it is fully
charged. If only one or no bars are present the
battery needs to be recharged.
Connect the instrument to the electric power supply
using the adaptor/recharge unit. The battery will be
recharged in 12 hours.
An abnormally high
absorbance reading is
obtained at one wavelength
Visually check the sample to ensure that there has
been no errors in the chemistry performed.
Check the condition of the filter. Deterioration of
the filter could cause higher absorbance readings.

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Issue 02 - 12/2003 CO 7500, English 6
IMPORTANT WARNING
This colorimeter has been designed for non toxic water based solutions. If
stronger solutions or dangerous or aggressive chemicals have to be used then
they must be treated with great care and be contained in properly stoppered
glass cuvettes.
Never cover the end of a cuvette by the thumb or finger to shake the contents.
Never pipette by mouth.
ACCESSORIES, CONSUMABLES AND SPARES
S2000P serial printer (includes serial cable) 80-3000-94
Spreadsheet interface software 80-2112-23
Serial interface cable 80-3001-00
Pack of 100 disposable cells, 1ml minimum volume 80-3000-60
Pack of 100 disposable cells, 0.5ml minimum volume 80-3000-76
Adapter set for 10 and 12mm tubes 80-3000-57
Spare filter set 80-3000-58
Spare lamp 80-3000-59
OUTPUT OF RESULTS
Use with serial printer
The instrument is designed to print to a serial printer at 9600 Baud with the S2000P
serial printer and cable. Output is automatic when R / T is pressed and the printer is
connected and switched on.
Use with PC
Results can be downloaded directly to Excel when the PC has the Spreadsheet
Interface Software installed (80-2112-23) and the two are linked with the serial
cable (80-3001-00); detailed instructions are supplied with the software. Baud rate
is 9600 and the separator should be set to space.
Use with chart recorder
The instrument can be connected to an analogue chart recorder using the 2 x 4 mm
banana plug sockets. The output is 0-2V for 0-2A and 0-1.99V for 0-199%T. A
standard chart recorder cable should be sourced locally.

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Issue 02 - 12/2003 CO 7500, English 7
MAINTENANCE
General maintenance
The instrument has no serviceable parts.
The instrument requires little maintenance. The following are considered good
practice:
1. Always disconnect from the mains supply when not in use.
2. Keep the instrument clean and dry immediately wipe off any spilt liquids.
Clean with a slightly damp cloth; a non-abrasive water-based soap or detergent
may be used.
3. Remove the cuvettes from the instrument when not in use.
4. At regular intervals check the mains power adaptor and cable for wear and tear
and replace if damaged.
5. Store in a cool place away from corrosive chemicals or fumes.
Changing a filter
Ultimately the filters may need replacement depending on the environment. High
humidity will cause the filters to fail more rapidly. If a filter does have to be
replaced, replace the whole set (part number 80-3000-58):
1. Disconnect from power supply.
2. Place the instrument upside down on a soft surface and unscrew the large grey
screw at the centre of the filter wheel. The filter wheel can then be removed.
3. Remove the filter to be replaced by pushing the locating clip back on the
underside of the filter wheel whilst pulling on the filter (a large flat head
screwdriver may help).
4. Insert a new filter ensuring that it clicks firmly into place.
5. Replace the filter wheel and tighten the screw finger tight.

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Issue 02 - 12/2003 CO 7500, English 8
Replacing the light bulb
1. Disconnect from power supply
2. Place the instrument upside down on a soft surface and remove the 4 screws in
the base using a No 1 Pozidrive cross head screwdriver.
3. Remove the lamp assembly fixing screw with a small flat screwdriver and
unplug.
4. Insert the new lamp assembly (part number 80-3000-59) and tighten the fixing
screw.
5. Replace the base of the instrument and tighten the 4 base plate screws.

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Issue 02 - 12/2003 CO 7500, English 9
SPECIFICATION AND WARRANTY
Wavelength range
440 –680nm
Standard gelatin filters
440, 470, 490, 520, 550, 580, 590 and 680nm
Bandwidth
40nm
Range
Absorbance –0.3A to 1.99A
% Transmission –0 –199% T
Accuracy
<±0.05A at 1A using Neutral Density Filters
Repeatability
±0.02A at 1A using cuvettes
Operational modes
Absorbance, Transmission, Kinetics
Cuvette holder
Fixed with drain hole. Accepts 10mm pathlength
semi micro and macro cuvettes or 16mm round tubes.
Can accept 10-12mm tubes with optional adapters
Output
0 –2V for 0 –2Abs or 0 –1.99V for 0 –199%T (via
2 x 4mm sockets, ~ 100mV offset in the output
voltage)
RS232
Power requirements
External power adaptor (110 to 220V, 50/60Hz,
20VA) or internal rechargeable NiMH battery
(mains/battery version only)
Approximate dimensions
180 x 150 x 60mm
Weight
0.6kg
Specifications are measured after the instrument has warmed up at a constant
ambient temperature and are typical of a production unit. As part of our policy of
continuous development, we reserve the right to alter specifications without notice.
The product does not fulfil the specific requirements of the IVD.
Warranty
Your supplier guarantees that the product supplied has been thoroughly tested to
ensure that it meets its published specification. The warranty included in the
conditions of supply is valid for 12 months only if the product has been used
according to the instructions supplied. They can accept no liability for loss or
damage, however caused, arising from the faulty or incorrect use of this product.
This product has been designed and manufactured by Biochrom Ltd, 22 Cambridge
Science Park, Milton Road, Cambridge CB4 0FJ, UK.