Unico S-1100 User manual

SPECTROPHOTOMETER
MODEL S-1100
Operation Manual
United Products & Instruments, Inc.
Dayton, NJ USA
www.unicosci.com 732-274-1155

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General Information
The spectrophotometer described in this manual is designed to be used by properly trained
personnel in a suitable equipped laboratory. For the correct and safe use of this
spectrophotometer it is essential that laboratory personnel follow generally accepted safe
procedures in addition to the safety precautions called for in this manual. The inside of the
power supply unit is a hazardous area and its cover should not be removed under any
circumstances. ANY Servicing must be done by an authorized person. Some of the chemicals
you use in the spectrophotometer may be corrosive, flammable, radioactive, toxic, and/or
potentially infective. Care should be taken to follow the normal laboratory procedures for
handling chemicals and samples.
Safety
This spectrophotometer has been designed and tested in accordance with EN 61326-1: 1997
Safety Requirements for Electrical Equipment for Measurement, Control, and Laboratory Use
standard (EMC Requirements). The spectrophotometer has been tested and supplied in a safe
condition. The safety statements in this manual comply with the requirements of the HEALTH
AND SAFETY AT WORK ACT, 1974.
Electrical
Before switching on the spectrophotometer, make sure it is set to the voltage of the local
power supply (see Installation section). The main plug shall be inserted in a socket provided
with a protective earth grounded contact. The protective action must not be negated using an
extension cord without a protective conductor.
Warning
Any interruption of the protective conductor inside or outside the spectrophotometer or
disconnection of the protective earth terminal is likely to make the spectrophotometer
dangerous. Intentional interruption is prohibited. Whenever it is likely that the protection has
been impaired, the spectrophotometer shall be made inoperative and be secured against any
unintended operation. The protection is likely to be impaired if the spectrophotometer
•Shows visible damage
•Fails to perform the intended measurements
•Has been subjected to prolonged storage under unfavorable conditions
•Has been subjected to severe transport stresses
Performance
Carry out performance checks with reference to wavelength and absorbance accuracy to
ensure that the spectrophotometer is working within its specification. Some performance
checks methods are detailed in this manual.
Interference
For compliance with the EMC standards referred to in the EC Declaration of Conformity, it is
necessary that only shielded cables supplied by UNICO are used when connecting the
instrument to computers and accessories.

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Introduction
The UNICO 1100 Spectrophotometers are single beam, general purpose instruments designed
to meet the needs of the conventional laboratory
Featuring a digital display of photometric result, easy operation, and wavelength range of
335 to 1000 nm, UNICO 1100 series are ideal for measurements in the visible wavelength
region of the electromagnetic spectrum.
Working Principle
The spectrophotometer consists of five parts:
1) Light Source (Halogen Lamp) to supply the light;
2) A Monochromator to isolate the wavelength of interest and eliminate the unwanted second
order radiation;
3) A Sample Compartment to accommodate the sample solution;
4) A Detector to receive and convert the transmitted light to an electrical signal;
5) A Digital Display to show absorbance or transmittance. Diagram below illustrates the
relationship between these parts.
Light Source Monochromator Sample Compartment Detector Digital Display
The light from the Halogen Lamp is focused on the entrance slit of the Monochromator where
the collimating mirror directs the beam onto the grating. The grating disperses the light beam
to produce the spectrum, a portion of which is focused on the exit slit of the Monochromator
by a collimating mirror. From here the beam is passed to a Sample Compartment through one
of the filters, which helps to eliminate unwanted second order radiation from the diffraction
grating. Upon leaving the Sample Compartment, the beam is passed to the silicon photodiode
Detector and causes the Detector to produce an electrical signal that is shown on the Display
Specifications
Model S-1100
Wavelength Range
335-1000 nm
Spectral Bandpass
20 nm
Wavelength Accuracy
± 2 nm
Wavelength Repeatability
± 1 nm
Stray Radiant Energy
< 0.5 %T at 340 and 400 nm
Photometric Range
0-125%T 0-2.0 Abs
Photometric Accuracy
± 2.0%T
Power Requirements
115/230 V ±10%, 60/50 Hz
Dimensions
408W X 308D X 185H (mm)
Net Weight
6kg (13 lbs)
100%T
0 A

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Unpacking Instructions
Carefully unpack the contents and check the materials against the following packing list to
ensure that you have received everything in good condition:
Packing List
Item Quantity
Spectrophotometer 1
Power Cord 1
Cuvette (round) Box of 12
Square Cuvette Adapter 1
Dust Cover 1
User’s Manual 1
Allen Wrench 1
Installation
Place the instrument on a dry, dust free lab bench top. In order to have the best performance
from your instrument, keep it as far as possible from any strong magnetic or electrical fields or
any electrical device that may generate high-frequency fields. Set the unit up in an area that is
free of dust, corrosive gases and strong vibrations. Remove any obstructions or materials that
could hinder the flow of air under and around the instrument. Turn on your spectrophotometer
and allow it to warm up for 15 minutes.
S-1100 Spectrophotometer

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1100 Spectrophotometer Operation Panel
Mode Indicator: Show the current measurement mode (T--%Transmittance, A--Absorbance)
MODE Button: Switch between T and Ameasurement modes.
0A/100%T Button: Adjust Digital Display reading to 100%T or 0.000A when blank reference
solution is in Sample Compartment.
Sample Compartment: Accepts 10 mm test tube or 10 mm square cuvette (the square cuvette
adapter is required).
WAVELENGTH (Wavelength Control) Knob: Select desired wavelength in nanometers (nm).
Wavelength Readout Window: Display desired wavelength.
Changing Sample Holders
Your spectrophotometer comes standard with a 10 mm path length Sample Holder which will
accept round tube, or square cuvets.
Follow the steps below to change the Cuvette Sample Holder:
•Open the lid of the Sample Holder and locate the Sample Holder Locking Screw
•Use the Allen Wrench (included) to loosen the Screw counterclockwise
•Remove the Sample Holder you want to change, insert the one you want to install, align
it properly, and fasten the Screw
Screw
Allen Wrench
Basic Operation
NOTE: OPERATING INSTRUCTIONS are printed on the front panel of the instrument.
Sample Preparation and Analysis
A. Spectrophotometer Warm-up
1. Turn on the spectrophotometer by turning on the Power Switch (IO). Allow a minimum
15 minutes for the instrument to warm up.
2. Select either the T(Transmittance Mode) or A(Absorbance Mode) by pressing the
MODE button until the red light for T or Ais on.
3. Select the desired wavelength by turning the WAVELENGTH control knob.

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B. Sample Preparation
1. Make a blank reference solution by filling a clean square cuvette (or test tube)
half full with distilled/de-ionized water or other specified solvent. Wipe the cuvette with tissue
to remove the fingerprints or droplets of liquid.
2. Insert the blank square cuvette into the square cuvette adapter and place the
adapter in the Sample Compartment (if using test tube, insert it directly into the Sample
Compartment, aligning the guide mark (if present) with the guide mark at the front of the
Sample Compartment). Close the lid.
3. Set 0.000A or 100%T with the 0A/100%T button.
NOTE: This step fulfills the instructions on the front of the spectrophotometer
4. Remove the blank square cuvette or test tube. Set it aside in case you may need to
adjust the 0A/100%T using 0A/100%T button later (i.e. change the wavelength).
C. Sample Analysis
1. Rinse a second square cuvette with a small amount of the sample solution to be tested.
Fill the square cuvette half full and wipe clean the exterior of the cuvette.
2. Put the sample cuvette in the Sample Compartment. Close the lid.
3. Read the Tor Afrom the Digital Display window. Remove the sample cuvette or
test tube.
4. If you are to test the same sample at other wavelengths, repeat step 3 to B. 1 –4
for each wavelength.
5. For each new sample you analyze, repeat step 2 to C. 4.
Output and Data Processing
USB Data Port
Model 1100 has a USB port which will allow you to interface with a Windows®based computer
for use with optional software, contact UNICO for details.
The Spectrophotometer Application Software is Windows-based software designed to operate
with your spectrophotometer using the USB port. The software runs on a PC with Windows®
XP/7/10 operating system installed. You can export data files collected from the
spectrophotometer into Excel®format if needed. The software offers two additional analytical
methods: Standard Curve and Absorbance vs. Time Kinetics. It performs the following
methods for analysis:
•Absorbance/%Transmittance/Concentration Measure the Absorbance,
%Transmittance, Concentration/Standard, or Concentration/Factor at a single wavelength
within the range of 335-1000 nm.
•Standard Curve Create a calibration curve (choice of 4 curve fits) with up to 8 standard
solutions at a single wavelength to determine concentrations of unknown samples.
•Absorbance vs. Time Kinetics Measure a sample’s absorbance change over a selected
period of time, store the results in a data table, and display the results graphically.

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Maintenance
Bulb Replacement
1. Turn off and unplug the instrument. Carefully turn the instrument upside down, making
sure no cuvette or chemicals are in the Sample Holder.
2. Remove the grill plate on bottom of the instrument by removing the screw.
3. Unplug the bulb from the white connector. Insert the new bulb by pushing it in as far as it
will go.
CAUTION: DO NOT HANDLE THE BULB WITH BARE FINGERS. USE TISSUE OR CLOTH WHEN
HANDLING LAMP.
4. Turn on the instrument. Set the wavelength at 340 nm, insert a test tube or an empty
cuvette with cuvette adapter, and blank the instrument. If the energy is low, adjust the
lamp by “pulling” or “pushing” it so that the light beam is focused on the entrance slot of
the monochromator. Since the lamp socket is pre-aligned, there will be little, if any,
adjustment required.
5. Re-install the grill plate.
Wavelength Calibration Check
Normally the 1100 Series spectrophotometer retains its wavelength calibration indefinitely.
However if the instrument receives a severe shock, or is shaken during transit or is abused, use
the following methods to check wavelength calibration. Please note that this test requires the
use of a didymium filter or a holmium oxide filter. Contact Carolina for availability and pricing of
these filters.
In the filter method, the didymium filter has two distinct absorbance peaks at 529 nm and 807
nm. The holmium filter has a distinct peak at 361 nm. When the instrument is calibrated
properly, you will find minimum Transmittance (maximum Absorbance) at the range ± 2 nm
from these peaks. Note that the specific Transmittance values are not important as you are
looking only for the wavelength where the minimum Transmittance (maximum Absorbance)
occurs.
Note: If your calibration filter has a certified peak/valley curve attached, please use the peaks
on the curve to verify the instrument.
Holmium Oxide Filter Method
1. Turn instrument on and allow it to warm up for 15 minutes.
2. Select the Amode.
3. Set the wavelength to 350 nm.
4. Make sure the cuvette adapter is empty and place it in the Sample Compartment. Close the
lid.
5. Set zero Absorbance by pressing the 0A/100%T (∧)button. Wait a few seconds when the
display flashes. The reading should be 0.000A. If not, repeat step 5.
6. Remove the Cuvette Holder and insert the Holmium filter into it. Place it in the Sample

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Compartment again and close the lid.
7. Record the Absorbance reading on the Digital Display window.
8. Advance the wavelength setting by 1 nm and repeat steps 4 to 7.
9. Repeat step 8 until the wavelength setting reaches 370 nm.
10. Look for the maximum absorbance reading obtained, and this should be found within
359~363 nm. The wavelength accuracy of the unit is ±2 nm.
Didymium Filter Method
1. Set the Wavelength to 800 nm.
2. Make sure the cuvette adapter is empty and place it in the Sample Compartment. Close the
lid.
3. Set zero Abs by pressing the 0A/100%T (∧)button. Wait a few seconds when the display
flashes. The reading should then be 0.000A. If not, repeat step 3.
4. Remove the Cuvette Holder and insert the Didymium filter into it. Place it in the Sample
Compartment and close the lid.
5. Record the Absorbance reading on the Digital Display window.
6. Advance the wavelength setting by 1 nm and repeat steps 2 to 5.
7. Repeat step 6 until the wavelength setting reaches 815 nm.
8. Look for the maximum absorbance reading obtained, it should be within 805-809 nm. The
wavelength accuracy of the unit is ±2 nm.
9. If a “middle” wavelength check is desired, set the wavelength to 522 nm (optional)
10. Make sure the cuvette adapter is empty and place it in the Sample Compartment. Close the
lid.
11. Set zero Abs by pressing the 0A/100%T (∧)button. Wait a few seconds when the display
flashes. The reading should then be 0.000A. If not repeat step 11.
12. Remove the cuvette adapter and insert the Didymium filter into it. Place it in the Sample
Compartment again and close the lid.
13. Record the absorbance reading on the Digital Display window.
14. Advance the wavelength setting by 1 nm and repeat step 10 to 13.
15. Repeat step 14 until the wavelength setting reaches 536 nm. Again, look for the maximum
absorbance reading. It should be within 527-531 nm.
Absorbance Accuracy Check
Specification: ± 2% at 1A (65-3303)
The absorbance accuracy should be checked against a set of neutral density filters accurately
calibrated to the NIST standards. Contact your Carolina representative for more information.
Stray Light Check
Specification: Less than 0.5%T at 340 nm by ASTM (American Society for Testing and Materials)
E 387 (Molecular Spectroscopy and Separation Science Standards), also see www.astm.org

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A good indication as to whether the stray light level is within specification may be obtained as
follows:
1. Set the wavelength to 340 nm.
2. Set the MODE button to T.
3. With the square cuvette adapter in the Sample Compartment without a cuvette close
the lid and press the 0A/100%T (∧) button to set the display to 100.0%.
4. Remove the cuvette adapter from the Sample Compartment and close the lid. Make a
note of the reading that should be at or near 0.00.
5. Prepare a solution containing 50 mg/L of sodium nitrite (NaNO2) in distilled water and
fill a square cuvette with this solution.
6. Insert the cuvette into the cuvette adapter, place it in the Sample Compartment, and
close the lid. The display should read < 0.5%T. If the reading obtained in step 4is
greater than 0.00, it should be subtracted from the displayed reading to give the correct
reading for the stray light value.
Troubleshooting
PROBLEM Possible Cause Solution
Instrument
Inoperative
(Power indicator
has no light)
Power cord not connected to outlet
Plug instrument in.
Dead Power outlet.
Wrong voltage setting.
Change to a different outlet.
Internal fuse blown or defective electronic
component.
Call an authorized service
engineer.
Instrument can
not set 100%T
(0.000A)
No Cuvette Adapter in the Sample
Compartment.
Cuvette Adapter must be in
Sample Compartment to
open sample holder shutter.
Light beam blocked:
•Holder misaligned
•Shutter
Check sample holder.
Lamp is old or defective.
Replace lamp/bulb.
Lamp is off alignment.
Refer to lamp Replacement
instructions in this manual.
Defective electronic component.
Call an authorized service
engineer.
%T can not be set
to 00.0%T
Sample holder.
Remove Cuvette Adapter or
test tube.
Sample holder shutter.
May be stuck open, close
shutter.
Defective electronic component.
Call an authorized service
engineer.
Incorrect
Bubbles or particles in solution.
Check sample preparation

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Transmittance to
Absorbance
correlation
and analytical procedure.
Defective electronic component.
Call an authorized service
engineer.
Digital Display
does not change
Wrong wavelength setting.
Check sample procedure and
wavelength setting.
Insufficient sample volume.
Fill cuvette with more sample.
Stray sample preparation vapors.
Prepare the sample away
from the instrument. Use
proper ventilation.
Bubbles or particles in solution.
Check sample preparation
and analytical procedure.
Defective electronic component or loose
wiring.
Call an authorized service
engineer.
Instrument drift
and noise
Insufficient warm up time.
Significant temperature change.
Lamp not adjusted properly.
Check if lamp has been
properly installed or has
moved during transit.
Refer to lamp Replacement
instructions in this manual.
Lamp old or defective.
Replace with a new lamp.
Sample Holder Misaligned.
Refer to Lamp Replacement
instructions in this manual.
Unstable power supply
Defective or dirty detector or defective
electronic component.
Call an authorized service
engineer.
Incorrect readings
obtained
Insufficient sample volume.
Fill cuvette with more sample.
Wrong wavelength setting.
Failed to blank (0A/100%T).
Failed to set 0%T.
Check analytical procedure
and wavelength setting.
Check wavelength accuracy
Stray sample preparation vapors.
Prepare sample away from
instrument. Use proper
ventilation.
Bubbles or particles in solution.
Check sample preparation
and analytical procedure.
Instrument out of electronic calibration.
Call an authorized service
engineer.