Millipore Direct Detect User manual

User Guide
Direct Detect®Spectrometer

C
Made in Germany
The M logo, Millipore, Direct Detect, and Amicon are registered trademarks
of Merck KGaA, Darmstadt, Germany.
All trademarks of third parties are the property of their respective owners.
© 2014 EMD Millipore Corporation, Billerica, MA, U.S.A. All rights reserved.
00000833, Rev. D, 05/14
Notice
The information in this document is subject to change without notice and should not be construed
as a commitment by EMD Millipore Corporation (“Millipore”) or an affiliate. Neither EMD Millipore
Corporation nor any of its affiliates assumes responsibility for any errors that may appear in this
document.

Contents
1 Introduction............................................................................................................... 1
2 Components Supplied ............................................................................................... 2
3 Symbols Used in this User Guide.............................................................................. 3
4 Product Labeling........................................................................................................ 3
5 Safety Precautions .................................................................................................... 4
6 Installation................................................................................................................. 4
6.1 Packaging ........................................................................................................................................................4
6.2 Site Requirements.........................................................................................................................................5
6.3 Installation Configuration ..........................................................................................................................6
6.4 Unpacking and Setting up the Computer...............................................................................................6
6.5 Unpacking and Setting Up the Direct Detect® Spectrometer...........................................................6
7 Direct Detect® Spectrometer Parts and Functions.................................................. 8
7.1 General Technical Features.........................................................................................................................8
7.2 Direct Detect® Computer and Software .............................................................................................. 10
8 General Guidelines .................................................................................................. 11
8.1 Buffer components .................................................................................................................................... 11
8.2 Materials Required but Not Supplied................................................................................................... 11
9 Direct Detect® Assay-free Card and Sample Preparation..................................... 12
9.1 Direct Detect® Assay-free Card ............................................................................................................ 12
9.2 Sample Preparation ................................................................................................................................... 13
10 How to Use the Direct Detect® Spectrometer....................................................... 14
10.1 Accessing Direct Detect® Software....................................................................................................... 14
10.2 Loading and Installing the Card............................................................................................................. 15
10.3 Measurement .............................................................................................................................................. 16
10.4 Removing the Card .................................................................................................................................... 18
11 Switching from Direct Connection to Intranet Connection (Networking).......... 19
11.1 Reconfiguration Requirements............................................................................................................... 19
11.2 Changing from Direct Connection to Intranet Connection............................................................ 20
11.3 Changing from Intranet Connection to Direct Connection............................................................ 22
11.4 Changing Computer Network Settings Manually ............................................................................. 24

12 Troubleshooting ....................................................................................................... 26
12.1 General Information.................................................................................................................................. 26
12.2 Problems Indicated by Hardware Diagnostics Icon .......................................................................... 27
12.3 Problems Indicated by Instrument Status Light (top of instrument) .......................................... 28
12.4 Problems Indicated by Instrument Validation Icon .......................................................................... 29
12.5 Problem Indicated by Instrument Internal Humidity Icon.............................................................. 29
13 Maintenance ............................................................................................................ 30
13.1 Replacing the IR Source........................................................................................................................... 30
13.2 Replacing the Desiccant........................................................................................................................... 33
13.3 Cleaning........................................................................................................................................................ 35
13.4 Description of Instrument Validation Tests......................................................................................... 36
13.5 Running the Instrument Validation OQ and PQ Tests...................................................................... 39
13.6 Storage .......................................................................................................................................................... 39
14 Installation, Operation, and Process Qualification Protocol (Optional).............. 40
14.1 Installation Qualification Protocol (IQ)................................................................................................ 40
14.2 Instrument Hardware Diagnostic Protocol.......................................................................................... 40
14.3 Operation Qualification Protocol (OQ)................................................................................................. 42
14.4 Performance Qualification Protocol (PQ)............................................................................................ 42
14.5 Protein Measurement Verification ........................................................................................................ 42
14.6 Direct Detect® System IQ/OQ/PQ Report Summary......................................................................... 44
15 Specifications........................................................................................................... 45
16 Ordering Information .............................................................................................. 46
17 Technical Assistance................................................................................................ 47
18 EC Representative.................................................................................................... 47
19 Standard Warranty .................................................................................................. 47
Contents, continued

Direct Detect® Spectrometer User Guide 1
1 Introduction
The Direct Detect® infrared (IR)-based quantification system is an innovative combination of software-
controlled instrumentation and EMD Millipore Corporation’s advanced membrane technology, optimized
for biomolecule detection, quantification of proteins, and analysis of lipids/detergents. Biomolecules
are applied directly to a card-based hydrophilic polytetrafluoroethylene (PTFE) membrane that is
transparent in most of the infrared spectral region.
The Direct Detect® system measures amide bonds in protein chains, accurately quantifying an intrinsic
component of every protein without relying on amino acid composition, dye binding properties, or
redox potential. Protein concentrations from 0.25 to 5 mg/mL can accurately be determined from a
minimal sample volume (2 µL) without bio- or immuno-chemical staining. Sample analysis takes only
minutes and in most cases can be performed directly from the buffered or native solution.
Quantification of lipids and detergents requires a user-defined standard curve. Unknown mixtures can
be analyzed by determining the relative IR absorbance.
The system has been validated with proteins and cell lysates representative of those currently in use in
research laboratories.

Direct Detect® Spectrometer User Guide
2
2 Components Supplied
The Direct Detect® system includes the following components:
Figure 1. Components supplied
1A
1B
1C
1D
1E
1F
1G
1H
1A Direct Detect® spectrometer
1B Instrument power adapter with 4 power cord/plug configurations (EU, UK, US, Japan)
1C Data cable (crossover, 10Base-T Ethernet with RJ45 connectors)
1D Dell® Netbook computer with Direct Detect® Software installed
1E Computer power adapter with world-wide plug adapter
1F Netbook stand
1G Direct Detect® Assay-free cards (package of 50)
1H Direct Detect® spotting tray
Desiccant pack replacement (1, not shown)
Torx® TX20 screw driver for replacing the IR source (not shown)
Direct Detect® Spectrometer Quick Start Card (not shown)

Direct Detect® Spectrometer User Guide 3
3 Symbols Used in this User Guide
The following symbols are used throughout this user guide and/or on product labels, and the user shall
abide by indicated requirements:
Symbol Definition
YWarning alerts you to actions that may cause personal injury or pose a
physical threat.
Class I Laser
Product Class I Laser product, complies with 21 CFR Chapter 1, Subchapter J
iRead the documentation
hCatalogue number
fSerial number
MManufacturer
CCE conformity marking. Reference Declaration of Conformity for specific directives.
Do not discard with common solid waste at end of life. Segregate with other waste
electrical and electronic equipment (WEEE) and send to an appropriate facility for
recycling. For information on recycling electrical and electronic products in the
European Union, please visit www.millipore.com/weee.
Hot Surface
4 Product Labeling
Figure 2. Product label appears on both the back and the bottom of the instrument

Direct Detect® Spectrometer User Guide
4
5 Safety Precautions
Review and understand the safety precautions below before installing and operating the Direct Detect®
spectrometer.
YWARNING
● To avoid danger of electric shock, do not install the instrument in an area with a high humidity
level. Refer to Site Requirements in section 6.2.
● Do not touch the Ethernet cable or universal power adapter plugs with wet hands.
● To avoid potential shock hazard, choose the correct plug configuration and make sure that the
power adapter is plugged securely into a properly grounded AC power outlet. Make sure that
the connection between the cable and the instrument is secure.
● Always ensure that the power supply input voltage matches the voltage available in your
location.
● Use only the power supplies that were supplied by EMD Millipore Corporation for use with the
Direct Detect® system. Use of other power supplies may damage the system.
● Minimize power draw from other instruments on the same power circuit.
● Do not use with flammable or explosive liquids. Cards that have been spotted with samples in
flammable solvents must be dried prior to insertion into the instrument.
6 Installation
NOTE: For a full installation, operation, and process qualification protocol and checklist, refer to
section14.
6.1 Packaging
Inspect the packaging for damage upon receipt. If there are any signs of damage, contact
the responsible shipping company.
YWARNING: Do not put a spectrometer showing signs of damage into operation as this
may result in severe personal injuries and/or property damage.
Keep the original shipping boxes in case you need to return the spectrometer for servicing
or repair.
NOTE: Instruments will not be accepted for repair if not in original packaging. EMD
Millipore Corporation will provide shipping boxes for a charge if original packaging
has been discarded.

Direct Detect® Spectrometer User Guide 5
6.2 Site Requirements
The user must provide an installation site that meets the following requirements:
Space requirement Stable and horizontal base which is able to bear the weight of
at least 8 kilograms (kg)
A clearance of at least 25 centimeters (cm) at the
spectrometer rear side
Environment Temperature range: 18–35 °C
Humidity (non-condensing): less than 35% (relative humidity)
Temperature variation: less than 1 °C/hour
Humidity variation: less than 3%/hour
Do not install devices such as large electric motors, heaters,
welding equipment, radio transmitting equipment, units emit-
ting pulsed NMRs, or high-powered lasers in close proximity
to the Direct Detect® spectrometer. These devices can cause a
spectrometer malfunction.
Make sure that these types of devices are not connected to the
same electrical circuit as the Direct Detect® spectrometer.
Vibration Do not locate the Direct Detect® spectrometer near vibration
sources (centrifuges, vortexes, ventilation hoods, air
conditioners, etc.), or in rooms with intense floor vibrations.
Inductive electrical
interference
Do not install the Direct Detect® spectrometer near any
sources of potential inductive electrical interference (e.g.,
pumps, switching motors, microwave ovens, etc.), sources of
high energy pulses, or sources that might cause magnetic or
radio frequency interference.
Power supply Voltage range: 100–240 VAC
Frequency range: 50–60 Hz
Protection class: I
The power supply unit automatically adapts to most power
sources commonly used.
Make sure that the power supply is easily accessible at all
times.
Connect the Direct Detect® spectrometer only to a grounded
power outlet.
Take precautions to ensure uninterrupted power supply if there
is the potential for power supply issues (e.g., brownouts, power
surges, frequent thunderstorms, etc.)

Direct Detect® Spectrometer User Guide
6
6.3 Installation Configuration
The Direct Detect® spectrometer is configured to operate as a stand-alone unit
connected to the supplied Netbook computer (PC) using the factory-set standard IP
address (10.10.0.1).
6.4 Unpacking and Setting up the Computer
Unpack the Netbook computer, power adapter, and world-wide plug adapter from
the shipping box. Choose the plug adapter with the correct configuration for local
requirements and attach it to the plug. Plug the low voltage (round) end of the power
adapter into the power port of the PC, but do not plug the computer into a power outlet at
this time.
6.5 Unpacking and Setting Up the Direct Detect® Spectrometer
Remove all components from shipping boxes and lay out on work surface.
6.5.1 Positioning and Connecting Components (Figure 3)
1. Place instrument on bench and put Netbook stand on top of instrument. The
front tab of the stand fits into the slot on top of the instrument (5B in Figure5).
2. Place Netbook computer on stand.
Figure 3. Rear side - Connection ports
3A
3B
3C
3. Turn the instrument/computer assembly so that the rear of the instrument is
facing you (Figure 3).
4. Connect one end of the provided Ethernet cable to the instrument ETH/LAN
port (3A) and the other end to the PC network/LAN port (3B).

Direct Detect® Spectrometer User Guide 7
6.5 Unpacking and Setting Up the Direct Detect® Spectrometer, cont.
5. Connect the low voltage (round) end of the instrument power adapter to the
power port of the instrument (3C). Secure the connector with the clamp.
6. Choose the instrument power cord with the correct plug configuration for local
requirements and plug it into the power adapter.
7. Plug both the PC and instrument power cords into a grounded power outlet. A
surge protector is recommended.
YWARNING: To avoid personal injuries and/or property damage caused by
electrical power, connect the spectrometer and computer to
a grounded power outlet. Make sure that this power outlet
complies with IEC (International Electrotechnical Commission)
regulations.
8. Turn on the PC.
NOTE: The instrument is powered through the computer and does not have
a separate ON/OFF switch. It should be left on and powered up at all
times.
6.5.2 Initializing the Direct Detect® Spectrometer
1. Refer to the Direct Detect® Software User Guide for instructions on starting up
the software and logging in (section 1.2).
2. During initialization, the laser, IR source, and detector are switched on. The IR
source warms up, the scanner moves forward and backward several times, and
tones once. This phase takes several minutes, and the hardware diagnostics
icon is yellow. After the initialization has been completed successfully, the
hardware diagnostics icon turns to green, but the instrument validation icon
will be yellow (Figure 4). This indicates that the PQ test has expired and needs
to be run. Refer to section 13.5 for instructions on running the PQ test.
Figure 4. Instrument status icons
Instrument validation icon
Instrument internal humidity icon
Hardware diagnostics icon
NOTE: If the status indicator on either the instrument or the software is red or
remains yellow after initialization is complete and the PQ test has been
run, refer to section12, Troubleshooting.

Direct Detect® Spectrometer User Guide
8
7 Direct Detect® Spectrometer Parts and Functions
7.1 General Technical Features
7.1.1 The Instrument
The Direct Detect® spectrometer is a small compact FTIR spectrometer designed for
measuring IR absorbance.
Figure 5. Direct Detect® spectrometer
5A
5B
5C
5E
5G
5F
5D
Definition
5A Instrument module (with integrated electronics and optics)
5B Slot for Netbook stand tab
5C Direct Detect® automated card holder
5D Card insertion alignment arrow
5E Status light
5F Sample drying indicator light
5G Card insertion light
7.1.2 The Direct Detect® Automated Card Holder
The automated card holder (5C) accepts only 4-sample Direct Detect® Assay-free cards.
The top of the card holder module contains two LED lights located at the bottom right
corner (5F and 5G as viewed from the top).
The bottom LED light (5G) is green whenever an Assay-free card is inserted properly.
The top LED light (5F) is yellow whenever the drying system heater and fan are active.
Periodically (default setting is 15 minutes) the software will initiate a reference measure-
ment which must be performed without a sample card inserted in the card holder. If a card
is found in the card holder, the software will prompt you to remove it.

Direct Detect® Spectrometer User Guide 9
7.1.3 Connecting Ports and LEDs
The connecting ports (e.g., power, Ethernet) and the system diagnostic LEDs are on the
back of the instrument.
Figure 6. Direct Detect® Spectrometer rear side - Connecting ports and LEDs
6A 6B 6C 6E 6F 6G 6H 6I 6J 6K
6D
Type Definition
6A USB port Not available to user. For instrument service use only.
6B ETH/LAN port The ETH/LAN port connects the spectrometer to the Netbook
computer, using the supplied data cable (crossover, 10Base-T with
RJ45 ports).
6C TKD LED The green TKD LED indicates that the interferometer mirror is
within the data acquisition range. When data acquisition is
occurring, the light is bright green. The abbreviation TKD means
Take Data.
6D ACC LED The yellow ACC LED indicates that the network is accessing the
optics. During transition of measuring data the LED is light yellow.
The abbreviation ACC means Access.
6E DIR/ERR LED In normal operation mode the DIR/ERR LED flashes pale red and
indicates scanner movement. If the LED lights permanently bright
red, there is an interferometer problem, e.g., missing laser signal.
When this LED is permanently red no data acquisition is possible.
The abbreviation DIR means Direction and ERR means Error.
6F External
accessory port
Not available to user. For instrument service use only.
6G TAP port Not available to user. For instrument service use only.
7.1 Direct Detect® Spectrometer General Technical Features, continued

Direct Detect® Spectrometer User Guide
10
Type Definition
6H CFG switch CFG is a four-fold DIP switch:
#1 ON and #2 OFF: DHCP mode - use last DHCP address
#1 OFF and #2 ON: use ON-IP address 10.10.0.1
#3: stay in boot loader, do not load the application program
#4: reserved
The abbreviation CFG means Configuration.
6I SBY/RES button Pressing this button for approximately 2 seconds, activates/
deactivates the stand-by mode. Pressing this button for more
than 6 seconds resets the spectrometer to the original state. The
abbreviation SBY means Standby and RES means Reset. Do not use
unless instructed to do so by service personnel.
6J POWER port This port connects the spectrometer to the power supply via the
supplied power adapter and power cord. The POWER port is for
extra low-voltage connectors. Use only power cords/supplies that
have been supplied by EMD Millipore Corporation.
6K Kensington lock
slot
The lock slot is an anti-theft lock for mobile hardware. Lock and
cable are not supplied.
7.2 Direct Detect® Computer and Software
The Direct Detect® spectrometer is designed to operate with the Direct Detect® Software
that is pre-installed on the Netbook computer. For computer specifications, refer to
section 15.
Direct Detect® Software may be updated periodically. For information on the most up-to-
date software, go to www.millipore.com/directdetect. Register your instrument in order to
receive notification about relevant software upgrades.
WARNING: Do not install third-party software (screen savers, etc.), as this may impact the
performance of the Direct Detect® system.
7.1 Direct Detect® Spectrometer General Technical Features, continued

Direct Detect® Spectrometer User Guide 11
8 General Guidelines
The Direct Detect® spectrometer is recommended for use with protein samples ranging from 0.25 to
5mg/mL. Although the instrument can measure protein concentrations from 0.1 mg/mL to around
30mg/mL, the most accurate results are achieved within the recommended concentration range. The
instrument is also capable of detecting and analyzing lipids and detergents. Analysis is performed with
a user-defined calibration method. Samples to be analyzed are introduced to the system using the
Assay-free card which contains a novel IR-compatible membrane. The recommended sample volume is
2 µL per spot position.
8.1 Buffer components
The Direct Detect® system is compatible with most commonly used buffers, detergents, and
reducing agents, however, use of buffers which contain amides or amine functional groups
may affect quantification.
Buffers containing more than 5% glycerol, SDS, and/or Tween® 20 surfactant should be
avoided due to the excessive time required to achieve dryness.
The instrument comes with preloaded protein calibration files, prepared using National
Institute of Standards & Technology (NIST) bovine serum albumin (BSA) in phosphate-
buffered saline (PBS). However, preparation of a fresh calibration method with the
buffer used for protein preparation is recommended. The Direct Detect® spectrometer is
compatible with most solvents used in lipid research.
8.2 Materials Required but Not Supplied
● Protein standards (Bovine Serum Albumin - National Institute of Standards &
Technology SRM 927d (optional))
● Protein sample(s)
● Lipid/detergent standards
● Lipid/detergent sample(s)
● Fixed-volume precision pipette capable of precisely dispensing 2 µL, and pipette tips
NOTE: To minimize pipetting error, we recommend the use of a fixed-volume precision
pipette capable of dispensing 2 µL, for applying samples to the Assay-free card.
Adjustable pipettes are not recommended.
● Water, PBS, or other buffer
● Chloroform or other lipid compatible solvent
● Printer (optional)

Direct Detect® Spectrometer User Guide
12
9 Direct Detect® Assay-free Card and Sample Preparation
9.1 Direct Detect® Assay-free Card
All concentration measurements are performed using the Assay-free card.
Figure 7. Direct Detect® Assay-free card
The card contains four hydrophilic polytetrafluoroethylene (PTFE) membrane positions,
sized for easy sample application and surrounded by a hydrophobic ring that retains the
sample to be analyzed within the IR beam. A 2 µL sample volume is recommended in order
to assure proper sample application, drying, and measurement.
By design, the positions on the card are numbered from 1 to 4, starting from the bottom.
Position 1, by software default, is reserved for the “blank” measurement. The “blank” is the
buffer/solvent used to resuspend the sample, but contains no protein or lipid/detergent.
One or more of the remaining card positions are used for the protein and/or lipid/detergent
samples.
The Assay-free card can be inserted into the system and analyzed immediately after
preparation. The Direct Detect® spectrometer has a built-in drying system that
automatically dries the sample to the point where it gives an accurate reading. The first
sample position typically takes the longest period of time to dry, with subsequent positions
taking less time. Including drying time, the total measurement time for a card loaded with
2 µL samples does not exceed 5 minutes.
The Direct Detect® Assay-free card is intended for one-time protein and/or lipid/detergent
spotting. However, already prepared cards can be stored and read again.

Direct Detect® Spectrometer User Guide 13
9.2 Sample Preparation
In general, analysis of protein samples within the concentration range of 0.25–5 mg/mL
can be performed directly from the buffered solution. Buffers containing more than 5%
glycerol, SDS, and/or Tween® 20 surfactant should be avoided due to the excessive time
required to achieve dryness.
For analysis of samples with protein content above 5 mg/mL, single step dilution is
recommended.
Concentration determination of samples below 0.25 mg/mL can be achieved after a simple
spin concentration step using a centrifugal filter (e.g., Amicon® Ultra-0.5 device).
Use of centrifugal filters is also recommended for buffer exchange when the original buffer
contains a high concentration of components with amide- or amine-containing functional
groups. Figure 8 is an example of a diafiltration protocol that concentrates the sample and
reduces the Tris buffer concentration.




















500 µL of
0.1 mg/mL
protein in
50 mM Tris










50 µL of
1 mg/mL
protein in
50 mM Tris
50 mM
Tris










50 µL of
1 mg/mL
protein in
PBS with 9.5
mM Tris
PBS with
9.5 mM Tris
Add 450 µL of
1X PBS or
exchange buffer
500 µL of
0.1 mg/mL
protein in
PBS with 9.5
mM Tris
Spin to
concentrate Spin to concentrate
Figure 8. Buffer exchange and concentration using an Amicon® Ultra-0.5 device
In general, lipid sample preparation involves solvent extraction. Neutral lipids may be
extracted by relatively nonpolar solvents such as hexane, chloroform, or toluene while
membrane-associated lipids require polar solvents like methanol or ethanol.
Lipids dissolved in organic solvents may be applied directly onto the Assay-free card.
Special care in the application of highly volatile solvents (chloroform, hexane, etc.) is
recommended in order to contain the samples within the hydrophobic embossing.
Analysis of detergents can be performed directly from buffer. Due to the excessive time
required to achieve dryness, samples containing more than 5% of the analyzed detergent
should be avoided.
The limits of lipid and detergent detection and quantification should be established
experimentally for each compound analyzed.

Direct Detect® Spectrometer User Guide
14
10 How to Use the Direct Detect® Spectrometer
The instrument is controlled and operated by Direct Detect® Software installed on the Netbook
computer. Samples are introduced to the instrument module by inserting the Direct Detect® Assay-free
card into the card holder (Figure 11). An alignment notch on one corner of the card ensures correct
card insertion into the card holder.
10.1 Accessing Direct Detect® Software
The Direct Detect® Software can be accessed through the icon on the Netbook desktop.
Figure 9. Direct Detect® Software desktop icon
Each instrument user can be assigned a unique name and optional password (Figure 10).
NOTE: If 21CFR11 mode is enabled, a password is mandatory. Refer to section 1.3 in the
Direct Detect® Software User Guide.
The measurements performed by each user are stored and recalled based upon the user
name.
Figure 10. Direct Detect® login screen
For detailed instructions on starting up the software, refer to section 1.2 of the Direct
Detect® Software User Guide.
NOTE: A seven minute warm-up cycle is required after initial power-up and software
activation. The software will wait for seven minutes before allowing a sample
measurement to begin.

Direct Detect® Spectrometer User Guide 15
10.2 Loading and Installing the Card
1. Place the Assay-free card(s) on the spotting tray or other clean surface. Select an
appropriate buffer/solvent blank, preferably the same solution in which the protein
or lipid/detergent has been prepared. If that buffer/solvent is not fully characterized,
select the closest buffer/solvent possible. Pipette 2 µL of the buffer/solvent solution to
the default blank position on the card (position1).
2. Pipette 2 µL of sample to sample positions 2 through 4 as needed. Unused positions can
be loaded and read at a later time as long as the buffer/solvent blank is appropriate for
them. Card positions can be labeled if desired.
NOTE: Cards spotted with samples in flammable solvents must be dried at ambient
conditions prior to inserting the Assay-free card into the instrument. However,
for nonflammable samples, the Direct Detect® spectrometer has a built-in
drying system that can automatically dry the sample to the point where it will
give an accurate reading.
3. Insert the card vertically into the slot in the top of the card holder module with the
card facing left and the alignment notch in the corner of the card oriented towards the
center of the instrument.
Figure 11. Inserting sample card
The arrow on the bottom right side of the card should be aligned with the arrow on
the Direct Detect® card holder module (5D in Figure 5). Gently release the card and the
instrument will accept it for analysis.
When the card is inserted properly the instrument will respond by jogging the card
holder up and down briefly. The bottom green LED on Direct Detect® card holder
module will light and the system will produce a brief tone confirming correct
placement of the Assay-free card.
NOTE: The software will not allow sample measurement if the card is not inserted
properly.

Direct Detect® Spectrometer User Guide
16
10.3 Measurement
For detailed instructions on setting up a sample measurement, refer to section 2.2 of the
Direct Detect® Software User Guide.
10.3.1 General Measurement Procedure
1. Complete the sample measurement setup (Figure 12). Check the Dry sample
card box to allow the instrument to dry the sample.
Figure 12. Sample information
NOTE: The Direct Detect® system comes with three preloaded protein
calibration methods. These pre-existing methods may be used for
all future measurements, however, for accurate quantification, we
recommend preparation of a fresh calibration method for each buffer
used in sample preparation (refer to section 4.2 in the Direct Detect®
Software User Guide). Lipids and detergents can be analyzed using a
Relative Absorbance mode.
2. Click on the Measure Card button (Figure 13). The sample measurement takes
about a minute and the measurement progress is shown in the lower status bar.
Figure 13. Measure sample