Turner Designs Opti-Check User manual

Opti-Check™
Handheld Fluorometer
November 11, 2011
P/N: 998-0861
Revision A
TURNER DESIGNS
1995 N. 1st Street
San Jose, CA 95112
Phone: [phone]
FAX: [phone]

Opti-Check™User’s Manual
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Table of Contents
1.
Introduction
1.1
Description
3
1.2
Quick View Diagram
3
1.3
Inspection and Setup
3
1.4
General Information, Precautions & Cleaning
4
2.
Instrument Specifications
2.1
General Specifications
5
2.2
Optical Configurations for Applications
5
2.3
Cuvette Information
5
3.
Instrument Operation and Calibration
3.1
Instrument Power Up
6
3.2
Detection Channel Configuration
6
3.3
Calibration Overview
6
3.4
Calibration Procedure
7
3.5
Sample Analysis
8
3.6
Diagnostic Information
8
4
Sample Analysis Guidelines
4.1
Handling Samples
9
4.2
Positioning Samples
9
4.3
Linear Range and Quenching
9
4.4
Temperature Considerations
10
4.5
Data Quality
10
5
Applications
5.1
Fluorescein
11
5.2
PTSA
11
6
Quick Diagnosis Guides
6.1
Power / Battery / Screen Issues
12
6.2
Reading and Calibration Issues
13
7.
Warranty
7.1
Terms
14
7.2
Warranty Service
14
7.3
Out of Warranty Service
15

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1 Introduction
1.1 Description
The Opti-Check is a small, lightweight, highly durable handheld fluorometer ideal for quick
measurements in the field. Dual-channel capability enables measurement for both cooling
tower and boiler system applications. Simple to operate, the Opti-Check is a perfect tool for
system verification. The Opti-Check can be configured with two channels: Fluorescein, PTSA or
both.
1.2 Quick View Diagrams
1.3 Inspection and Setup
1.3.1 Inspection
Upon receiving your instrument, please inspect everything carefully and make sure all
accessories are present. All shipments include:
The Opti-Check
The User’s Manual on CD
4 - AAA batteries
Cuvettes –Qty 4
Storage Pouch

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1.3.2 Setup
Before the Opti-Check can be used, the supplied batteries must be installed.
1. On the back side of the instrument, remove the battery panel by loosening the center
screw and then gently pulling on the screw. There is some resistance due to the o-ring
which is used for watertight sealing (see Section 1.2 for diagram).
2. Install the 4 - AAA batteries and verify the batteries are positioned correctly.
3. Replace the battery panel and press it down into position.
4. Hold the battery panel down in place and gently tighten the screw until it is snug.
Do not over tighten the screw.
Note: If the battery panel is very difficult to press down or remove, you can apply a small
amount of silicon-based grease to lubricate the o-ring as needed.
1.4 General Information, Precautions and Cleaning
The sample compartment cannot accept 10 mm square cuvettes because the cuvette
wall thickness exceeds the 12 mm maximum outer dimension that the Opti-Check can
accept. The 10 mm size is the internal dimension of the cuvette and some plastic
cuvettes may be too large.
Do not force oversized cuvettes into the sample compartment. This can damage the
sample compartment. If the cuvette does not easily fit down inside the Opti-Check you
will need to purchase different cuvettes.
Use caution around solvents because they may attack the plastic case of the Opti-
Check.
If a sample is accidentally spilled inside the Sample Compartment, invert the Opti-Check
to drain out the excess liquid. Then wipe the inside area dry with a clean soft towel or
tissue.
If extra cleaning is needed, use a mild detergent to dampen the towel for cleaning.
Do not submerge the Opti-Check in water.
Do not expose the Opti-Check to temperatures outside the specified range of
5 to 40 °C or damage may occur to the unit that will not be covered under warranty.

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2 Instrument Specifications
2.1 General Specifications
Specification
Description
Size
1.75” x 3.5” x 7.25”
(4.45cm x 8.9cm x 18.4cm)
Weight
13.9oz (0.4kg)
Dynamic range
3 orders of magnitude
Resolution
12 bits
LCD Display
2 x 16 characters
Case
Meets IP 67 Standard; dustproof and watertight
Temperature
41-104 °F; 5-40 °C
Detector
Photodiode
Calibration Type
Single-point and blank
Error message
Low battery, High blank
Cuvette Type
Methacrylate
Warm Up Time
5 seconds
Auto Power Off
After 3 minutes of inactivity
2.2 Optical Configurations for Application (Channel)
Application
Light Source
Minimum
Detection Limit
Linear Range
Excitation
Emission
Temperature
Coefficients
Fluorescein
Dye
Blue LED
< 1 ppb
0 - 400 ppb
485 nm
540 nm
0.0036/°C
Exponential
PTSA
UV LED
< 1 ppb
0 –1000 ppb
365 nm
400 nm
-0.00126/°C
Exponential
2.3 Cuvette information
Cuvette type
Size
Usage
Part No.
Methacrylate plastic
10 mm Square
(height 44.5 mm)
Required for UV (< 400 nm), works for all applications.
Do NOT use with solvents
7000-959

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3 Instrument Operation and Calibration
3.1 Instrument Power Up
To turn on the Opti-Check, press the <ON/OFF> button. After a 5 second warm up, the
Opti-Check is ready for operation.
Pressing the <ON/OFF> button again will turn the unit off or if left idle for 3 minutes the unit
will turn itself off to save battery power.
A set of new batteries will last for over 1,000 sample readings. If the batteries have low
power or are not positioned properly, the following warning message will be displayed –
“Batt Level < 20% !! Caution !!”.
The contrast of the display can change with temperature and will get lighter as the unit gets
colder. The contrast can be easily adjusted. Press the arrow button to darken the
contrast and press the arrow to lighten the display contrast.
3.2 Detection Channel Configuration
The Opti-Check can be configured with one or two optical channels. To identify the
configuration look at the label on the back side of the Opti-Check.
The <A/B> button allows the user to toggle between the 2 channels. The display will show a
label in the lower left corner of the Home screen to identify which channel is activated.
3.3 Calibration Overview
The Opti-Check can be calibrated using a Primary standard. A Primary Standard is one that
contains the same fluorescent material that you are measuring in your unknown samples.
The Opti-Check will give an actual quantitative concentration reading when a primary
standard of known concentration is used for calibration.
The standard and samples must be in the linear detection range to get accurate quantitative
results. Refer to Section 5.3 for more details about the linear range and quenching of the
samples.
For Dye tracing applications the calibration is normally performed with a primary standard
made from the same dye that is being used for the testing. The primary standard will either
be made to a known concentration, typically in ppb or µg/L units, or to a known dilution
factor. Ideally the Primary Standard and Blank samples used for calibrating will be made
with the same water the tests are being performed in.

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3.4 Calibration Procedure
It is recommended for best accuracy, that you always calibrate before performing your
sample analysis. The Opti-Check will save the calibration settings for each channel until a
new calibration is performed.
If the temperature of your samples or the Opti-Check changes significantly, the readings
may show a small shift and in this case, you should consider recalibrating.
The Opti-Check is designed with “ambient light rejection”. The black sample compartment
cover does NOT need to be closed when calibrating or reading samples.
The orientation and cleanliness of the cuvettes can have an impact on the accuracy of your
results. Refer to Section 4, Sample Analysis Guidelines for information to help ensure the
best results for your analysis.
3.4.1 Assign a Calibration Standard Value.
This defines the numeric value that you want the standard to read. For example, if you
calibrate with a primary standard that has a concentration of 100ppb, then you will set
the value to 100 and the implied unit of measure will be in ppb.
3.4.1.1Press the <STD VAL> button.
3.4.1.2Use the and arrow buttons to set the standard value. Pressing the arrow
button once quickly will make a small incremental change to the value. Holding
either arrow button will allow you to change the value using fast scrolling.
3.4.1.3When finished, Press the <ENT> or <ESC> button to accept the value and to
return to the Home screen.
3.4.2 Perform the Calibration.
3.4.2.1Press the <CAL> button.
3.4.2.1Press <ENT> to start the calibration.
3.4.2.3Insert your blank sample and press <ENT>. The Opti-Check will average the
reading for 10 seconds and set the blanking zero point.
3.4.2.4Insert the standard sample and press <ENT>. The reading is averaged for 10
seconds and the Standard Calibration value is set.
3.4.2.5Press <ENT> when the calibration is complete to accept the calibration. If
<ENT> is not pressed within 10 seconds, you will be asked if you want to abort
the calibration. Press the or arrow button to abort or accept the calibration
respectively.
If at anytime during steps 1-4 you want to stop the calibration, press <ESC>.
This will return you to the Home screen and will default the instrument to the
previous calibration.

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3.4.3 Calibration Check
Once the Opti-Check calibration is accepted, press the <DIAG> button to see what
your standard to blank ratio is. The standard to blank ratio is defined as the %FS
blank as compared to the %FS standard. The %FS signal should be at least 5 times
larger than the %FS Blank. It should be between 5 and 30.
If your %FS std:%FS blk ratio is greater than 30, dilute your Calibration
Standard accordingly and recalibrate. Check the ratio again.
If your ratio is less than 5 you'll have to find a different standard for calibration.
If your ratio falls between 5 and 30 after the initial calibration then you can start
measuring samples.
3.5 Sample Analysis
1. Insert your sample. The Opti-Check is designed with “ambient light rejection”. The
black sample compartment cover does NOT need to be closed when reading samples.
The orientation and cleanliness of the cuvettes can have an impact on the accuracy of
your results. Refer to Section 5 for more details.
2. Press the <READ> button. The instrument will measure and average the fluorescence
signal for 5 seconds.
3. The reading result will be displayed on the top line of the Home screen.
4. The top left corner will then display “WAIT” for 5 seconds. Once “WAIT” disappears,
another sample reading can be performed.
3.6 Diagnostic Information
1. Press <DIAG> to access the diagnostic screens.
2. Press <ENT> to toggle to the %FS (Full Scale) values for the blank (Blk) and standard
(STD) calibration points. The STD value should be at least 5 times larger than the Blk
value to ensure consistent results. This is often referred to as the Standard to Blank
Ratio.
3. Press <ESC> when finished to return to the Home screen.

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4 Sample Analysis Guidelines
4.1 Handling Samples
4.1.1 Take care not to spill samples into the sample chamber. Wipe up any spills
promptly.
4.1.2 The cuvette MUST BE DRY on the outside when taking readings. Any moisture or
condensation on the outside of the cuvette can affect the reading.
4.1.3 Fill the cuvette with at least 2mL solution volume or at least 2/3 full. Significant error
in the readings can result if the cuvette contains less than this minimum volume.
4.1.4 The Opti-Check is very sensitive and even small amounts of material from a previous
sample may contaminate the sample and result in errors. Use a clean cuvette for all
readings. If you are using the same cuvette for your samples it is very important that
you thoroughly clean the cuvette between samples. A good way to confirm the
cuvette cleanliness is to read a blank solution. If the reading is higher than the
normal blank reading, the cuvette is not clean.
4.1.5 Any bubbles in the sample will affect the readings. Take care not to introduce
bubbles into samples. Remove any bubbles by lightly tapping with your finger on the
outside cuvette wall or cover the top of the cuvette and tilt the sample to help
dissipate bubbles.
4.2 Positioning Samples
The orientation of the cuvette in the sample compartment can give slightly different readings
especially for low concentration samples. This is due to variations in the walls of the cuvette
that are not readily visible to the eye. We recommend that the cuvette be marked at the top
on one side and positioned in the sample compartment the same way each time for best
results.
4.3 Linear Range and Quenching
The linear range is the concentration range in which the readout of the Opti-Check is directly
proportional to the concentration of the fluorophore in the sample. The linear range begins
with the lowest detectable concentration and spans to an upper limit concentration that is
dependent on the properties of the fluorescent material and the cuvette optical path length.
For Fluorescein dye in the 10 mm square cuvette, the upper limit of linearity is approximately
400 ppb.
At concentrations above this upper limit, the fluorescence reading will not increase at a
linear rate in comparison to the change in concentration. At concentrations 10 times higher
than the upper limit, the readings will start to decrease even though the sample
concentration is increasing.
This effect is known as "sample quenching" and is due to light absorption losses in the
sample. See the Figure 1 graph below.

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When you start to see visual color in the sample, this is an indicator that the sample may be
above the upper limit of linearity. The linearity can be verified by diluting a sample 1:1 or
another convenient dilution ratio. If the sample is within the linear range, the reading will
decrease in direct proportion to the dilution. If the reading does not decrease in direct
proportion to the dilution or if the reading increases, the original sample concentration was
above the linear range.
Figure 1. Linearity and Calibration Response Curve
4.4 Temperature Considerations
Fluorescence is temperature sensitive. As the temperature of the sample increases, the
fluorescence decreases. For best accuracy make sure your samples are at the same
temperature as the calibration standard. If you have the ability to measure sample
temperature, a temperature coefficient may be applied to your measurements, see section
2.2.
4.5 Data Quality
The Opti-Check is only as accurate as the standards that are used to calibrate it. This is
why it is important to take care when preparing standards, samples, and blank. One should
follow good laboratory practices when preparing all solutions and samples.