HPLC System Selection

Gamal A. Hamid2
Contents
• Introduction
• Instrument
• Pump
• Solvent rack
• Autosampler
• Column
• Column compartment
• Detector
• Applications
• Food applications

Gamal A. Hamid3
Chromatography
Chromatography
Is a physical method of separation in which the
components to be separated are distributed
between two phases, one of which is stationary
(stationary phase) while the other (the mobile
phase) moves in a definite direction. ( IUPAC)

Gamal A. Hamid4
HPLC
High-performance liquid chromatography (HPLC;
formerly referred to as high-pressure liquid
chromatography),
• Is a form of liquid chromatography where the
high pressure used to separate the mixture
components, then identify and quantify.

Gamal A. Hamid6
High pressure liquid chromatograph
HPLC instruments consist of:
I. Solvent rack,
II. Pump,
III. Injector,
IV. Separation column,
V. Detector.

Gamal A. Hamid7
Basic Systems
Basic manual system
Basic automated system
Isocratic pump + manual sample
injection + detector.
A simple, expandable system
where modularity makes
anything possible.
Isocratic or
quaternary
or binary
pump 620 bar
+ integrated
autosampler
+100 Hz detector

Gamal A. Hamid8
Standard Systems
The system model named according the used pump:-
• UltiMate 3000 Standard Binary System
• UltiMate 3000 Standard quaternary System
• UltiMate 3000 Standard dual System

Gamal A. Hamid9
Rapid separation systems
Rapid Separation (RS) Systems
• Pressures up to 1034 bar at flow rates up
to 5 mL/min.
• Pressures of 800 bar at flows from 5 – 8
mL/min.
• Binary, Quaternary, and Dual-Gradient
Pumps.
• Column Temperatures from 5 – 110°C.
• Optional switching valves for advanced
workflows.
• 200 Hz DAD, MWD, VWD, FLD

Gamal A. Hamid10
Benefits of UHPLC
 Faster Analysis (typically 10X faster)
• Increased productivity (more samples/day)
• Higher instrument ROI (more samples/system)
• Faster results (e.g. decreased time to market)
• Increased data content (more data in the same time)
 Reduced Solvent Consumption (typically 10X reduction)
• Lower solvent acquisition costs
• Lower solvent disposal costs
• Reduced environmental impact

Gamal A. Hamid11
Select your system SD or RS

Gamal A. Hamid12
Pumps
Autosamplers
Column
compartments
Detectors
The UltiMate®
3000 LC Systems
With ValvesStandard
Quaternary Dual-GradientBinary
VWD/MWD/DAD Fluorescence
Standard Thermostatted +FractionationBasic
Isocratic
Coulo chemCorona

Gamal A. Hamid13
I. Pump
A device designed to deliver the mobile phase
at a controlled flow-rate to the separation
system.
• Isocratic analysis in which the eluent
composition remains unchanged during the
analysis. solvent must be pre-mixed
• A gradient analysis allows the composition of
the eluent to be changed during the analysis.
The heart is the Strongest pump ever

Gamal A. Hamid14
The UltiMate®
3000 SD & RS pumps
• First select a pump that match with
your applications.
• Four different Standard “SD” pumps,
• And three Rapid Separation “RS”
pumps.

Gamal A. Hamid15
Pump components
No Description
1 Peristaltic pump
2 Detector of the rear seal wash system
3 Capillary guides
4 Pump head with working cylinder and
equilibration cylinder
5 Leak sensor
6 LPG-3400SD and RS: Capillary mixer
LPG-3400BM: Capillary from purge to inline filter
7 4-channel vacuum degasser
8 Pump lights
9 LPG-3400SD and RS: Static mixer LPG-3400BM:
Inline filter
10 Purge unit with purge valve and pressure
transducer for the system pressure
11 Pump block status LED
12 4-channel proportioning valve

Gamal A. Hamid16
1. Isocratic pump ISO
The mobile phase, either a pure solvent or a mixture, remains the same throughout during
the run, Solvents must be pre-mixed. Without degasser.

Gamal A. Hamid17
2. High-pressure gradient pump HPG
• High-pressure gradient pump with integrated mixing
chamber and "2 from 4" solvent selectors Two pumps are used.
• The eluents are mixed after pumping. Accurate gradient and minimized delay volume.
• Without degasser.
• Response of the gradient is superior because of the small volume from the mixing unit to the column.

Gamal A. Hamid18
High-pressure gradient pump HPG
HPG-3400
HPG-3200

Gamal A. Hamid19
3. Low pressure gradient pump LPG
• One pump is used for mixing, Up to four eluents can be mixed.
• With degasser.

Gamal A. Hamid20
4. Dual gradient pump DGP
• Two separate pumps with integrated mixing chambers in one enclosure (2x3 solvents).
• Two different pumps with different solvents and columns. Without degasser.
• Independently-optimized mobile phase composition for 2D separations.

Gamal A. Hamid21
Flow rate & pressure

Gamal A. Hamid22
Eluents flow diagram

Gamal A. Hamid23
RS & SD Pumps

Gamal A. Hamid24
Pump Chromeleon page

Gamal A. Hamid25
II. Solvent Rack
• Second select your Solvent rack
that match with your pump
selection.
• How many channel you have in
your pump?
• Is your selected pump has
degasser or not?

Gamal A. Hamid26
Solvent Rack “SR”
1. SR-3000 Solvent Rack
Without vacuum degasser typically for use with a
LPG-3400, ISO-3100BM, or HPG-3200BX
2. SRD-3200 Solvent Rack
With analytical 2-channel vacuum degasser typically
for use with the following pumps: - one HPG-3200
(SD or RS) - one ISO-3100SD

Gamal A. Hamid27
SRD “Solvent Rack Degasser”
• With analytical 4-channel vacuum degasser
typically for use with the following pumps:
- one HPG-3400 - two HPG-3200 (SD or RS)
pumps in a two-stack system - one HPG-
3200 (SD or RS) or ISO-3100SD if you want
to degas the solvents and the wash
solution of autosampler
• With analytical 6-channel vacuum degasser
typically for use with the following pumps:
- one DGP-3600 - two HPG-3200 (SD or RS)
pumps in a two-stack system - one HPG-
3200 (SD or RS) and one HPG-3400 in a
two-stack system - one HPG-3400 if you
want to degas the solvents and the wash
solution of autosampler.

Gamal A. Hamid28
Specifications

Gamal A. Hamid29
3. Injector Instrumentation
• A device by which a liquid, solid or gaseous
sample is introduced into the mobile phase
or the chromatographic bed.
• The injector must also be able to withstand
the high pressures of the liquid system.
• Each type is equipped with six-port valves, so
that a sample can be injected into the flow
path at continuous pressure.

Gamal A. Hamid30
In-line Split-Loop autosamplers “SL”
• The in-line split-loop (SL) (flow-through)
analytical autosampler supports pressures up
to 62 MPa (9000 psi) at analytical and micro
flow rates.
• Within in-line split-loop autosamplers, the
sample loop, needle, and needle seat are
integral parts of the high pressure fluidic path.
• Autosampler aspirates only the sample volume
injected onto the column. The needle and
sample loop are constantly rinsed with mobile
phase, achieving the lowest carryover.

Gamal A. Hamid31
Pulled-Loop Autosamplers “PL”
• In pulled-loop autosamplers, the needle is not
an integral part of the high pressure fluidic
path.
• Therefore, all autosampler parts in contact
with the sample can be made of inert
material.
• High injection precisions are achieved in full-
loop injections at a fixed-sample loop volume.
• Variable injection volumes are accessible in
partial loop injection mode.

Gamal A. Hamid32
Features and Benefits
SL BL
• High injection volume flexibility
• Near zero carry over
• No sample loss
• Low sample dispersion
• Excellent injection precision and linearity
• Very short cycle times
• Highest versatility and product
• Lowest injection volumes down to the nL
range
• Biocompatible flow paths*1
• Microliter pick-up – zero sample loss for
pulled-loop injections
• Excellent injection precision even at low
volume injections – at 20 nL a precision <
1% can easily be achieved.
• Optional fractionation capabilities

Gamal A. Hamid33
Autosampler configurations
• T Thermostatted
• SL Split Loop
• PL Pull Loop
• B Bio compatible
• A Analytical
• RS Rapid Separation
• FC Fraction Collector
• X MS

Gamal A. Hamid34
Definitions
T The sample thermostatting option allows sample cooling using peltier by max. 22 °C from the ambient
temperature. The lower temperature limit is +4 °C. In addition, the samples can be warmed to max. +45 °C.
SL In-Line Split Loop flow autosampler the needle is an integral part of the high pressure fluidic path.
PL Pulled Loop autosampler the needle is not an integral part of the high pressure fluidic path.
B Biocompatible Autosampler perfectly matches the requirements for injections of complex samples
containing biomolecules, such as recombinant proteins or monoclonal antibodies.
Almost all descriptions of the standard autosamplers apply also to the biocompatible versions.
RS UHPLC Rapid Separation the 103 MPa (15,000 psi) in-line split-loop (flow-through)
FC The autosampler is equipped with one 2-position, 6-port injection valve and one 2- position,6-port
fractionation valve, With this configuration, injection, fraction collection, and reinjection
can be fully automated on one system.
X The 125 MPa (18,130 psi) in-line split-loop (flow-through) UHPLC autosampler for MS.

Gamal A. Hamid35
Autosampler Chromeleon page

Gamal A. Hamid36
4. Column Instrumentation
• Is The tube and the stationary phase
contained within, through which the mobile
phase passes.
• The heart of the chromatograph.
• The column’s stationary phase separates the
sample components of interest using various
physical and chemical parameters.
• The pump push hard to move the mobile
phase through the column and this resistance
causes a high pressure.

Gamal A. Hamid37
Column types
Name Description
1 Acclaim® Reversed-Phase Col. RSLC, PepMap, Polar Advantage
2 Acclaim Multi-Mode Columns
Trinity™ P-1
3 Acclaim Specialty Columns
Organic acids, surfactants,
explosive
4 ProSwift® Columns Monolith RP and ion exchange
5
PepSwift™ Columns RP nano, capillary and micro
columns
6 DNASwift™ Columns
Monolith SAX

Gamal A. Hamid38
Thermostatted Column Compartment TCC
• Accommodation of up to 12 columns, the maximum column length is 300 mm.
• Column switching valves make the TCC the appropriate choice for almost all applications in
HPLC and UHPLC.
• Homogeneous temperature distribution via a fan-based, forced-air design
• Column identification system and comprehensive system wellness features
• Titanium and PEEK valves are available for different bio-UHPLC and bio-HPLC applications.
• Pre-column heater brings the solvent and the sample to the column temperature before they
enter the column. This avoids temperature gradients in the column.
• Post-column cooler (only TCC-3000RS) cools the column eluate to a temperature that is
appropriate for the subsequent detection. Post-column cooling minimizes the noise values
and thus leads to optimal detection results.

Gamal A. Hamid39
Column Compartment TCC-3000 RS
• The Rapid Separation (RS) Thermostatted
• Wide temperature range from 5 (maximum 18
°C below ambient)–110 °C with excellent
accuracy and precision
• Optional column switching valves
• Post column cooling ensures lowest detector
noise and drift
• Column identification system for up to four
columns.

Gamal A. Hamid40
Column Compartment TCC-3000 SD
• The Standard (SD) Thermostatted Column
• Compartment is a cost-effective choice for
• conventional HPLC as well as bio
chromatography separations.
• Up to 80 °C and precolumn heating.
• TCC 3000 SD similar to TCC 3000 RS in the
most specifications except the temp.
range.

Gamal A. Hamid41
Column heating
Reproducibility
• If temperature varies, then it is difficult to assign “peaks”
to specific compounds in the chromatogram and the
peak areas/heights may vary
Solubility
• Certain chemical compounds may have low solubility in
the HPLC mobile phase
• If they are injected into the flow stream they may
precipitate or other difficulties may arise
Stability
• Certain chemical compounds, especially biological
compounds such as enzymes or proteins, may not be
stable at room temperature or higher
• The temperature needs to be much lower down to 4°C

Gamal A. Hamid42
Home page Chromeleon

Gamal A. Hamid43
5. Detector Instrumentation
A device that measures the change in the
composition of the eluent by measuring
physical or chemical properties.
The desirable features of a detector are:
• Sensitivity towards solute over mobile phase
• Low cell volumes to minimize memory effects
• Low detector noise
• Low detection limits
• Large linear dynamic range

Gamal A. Hamid44
UV/UV-VIS Detectors (variable λ detector)
• The Thermo Scientific™ Dionex™
UltiMate™ 3000 VWD-3000 is a variable
wavelength detector (VWD) series for
industry leading UV-VIS detection.
• flow cells ensure optimal performance
over a flow rate range of five orders of
magnitude.
1. Lamps cover
2. Flow cell
3. Flow cell drainage
4. Leak sensor

Gamal A. Hamid45
VWD Principle
• A UV detector employs a deuterium discharge lamp
(D2 lamp) as a light source, with the wavelength of
its light ranging from 190 to 380 nm.
• If components are to be detected at wavelength
longer than this, a UV-VIS detector is used, which
employs an additional tungsten lamp (W lamp).
• By monitoring the reference light divided from the
light in front of the flow cell, the difference in light
intensity can be determined between the back and
front of the flow cell, and this is output as
absorbance.

Gamal A. Hamid46
VWD Features and highlights
• Data collection rate:
Single wavelength up to 100 Hz (VWD-3100)
Single wavelength up to 200 Hz (VWD-3400RS)
Multiple wavelength up to 5 Hz (VWD-3400RS).
• Light source:
Deuterium lamp, tungsten lamp
(Tungsten lamp optional on VWD-3100)
Temperature control for both lamps
• Flow cells:
wide range of available ensure optimal
performance over a flow rate range of five
orders of magnitude,
Analytical flow cell, 11 μL, stainless steel
• Wavelength range:
190–900 nm with combined use of deuterium
and tungsten lamp on one optical axis.
• Temperature control of optics and electronics for
data acquisition independent of ambient
conditions.
• The detector’s large linearity range of up to 2.5
AU is ideal for applications with widely varying
analyte concentrations.
• The VWD-3000 series uses a fast-turning grating
monochromator placed in front of the flow cell.
• No. of Channels:
1 channel (VWD -3100 SD)
Up to 4 channels (VWD-3400 RS)

Gamal A. Hamid47
UV Detector Chromeleon page

Gamal A. Hamid48
Diode array detector (DAD, PDA)
• Photodiode arrays (semiconductor devices) are
used in the detection unit.
• The Thermo Scientific™ Dionex™ UltiMate™ DAD
3000 detector is a high-resolution, 1024-
element diode array detector (DAD) available in
Rapid Separation and Standard versions.
• Optical System, Single-beam, reverse optics
design with concave holographic grating.
• The detector is also available as a multiple
wavelength detector (MWD) in Standard and
Rapid Separation versions, MWD does not
support the acquisition of 3-D spectra .

Gamal A. Hamid49
PDA Principle
• The polychromatic beam passes the flow cell.
• The grating splits up the polychromatic beam to
different wavelengths, the intensities of which are
measured by an array or photodiodes.
• A photodiode is a semiconductor device that
converts light into current.
• The current is generated when photons are
absorbed in the photodiode.
1. VIS Lamp
2. D 2 Lamp
3. Flow cell Adaptor
4. Flow cell

Gamal A. Hamid50
DAD Features and highlights
Diode array detector (DAD) available in
Rapid Separation (200 Hz) using a
maximum of eight single-wavelength data
channels and one 3-D field (and Standard
(100 Hz) versions.
• Light source:
Deuterium lamp, tungsten lamp
Flow cells:
Flow cell range covers semi-micro, semi-
analytical, analytical, and semi-preparative
flow rate applications, in stainless steel and
biocompatible versions.
The tungsten and deuterium lamps emits
light in UV and visible ranges (190 -800) nm.
• Temperature control of optics and
electronics for data acquisition
independent of ambient conditions.
• A typical detector linearity up to 2.0 AU.
• Temperature control for both lamps.
Up to 8 channels (DAD-3000 SD)
Up to 8 channels (DAD-3000 RS)+ 3D

Gamal A. Hamid51
Fluorescence Detector
• Xenon lamp Light source for the UV to near-
infrared wavelength range.
• PMT Photomultiplier tube (PMT) - Converts the
emitted light to a measureable current signal.
• Fluorescence detection offers greater sensitivity
than a UV-VIS detector. However, the number of
naturally fluorescent compounds is smaller in
comparison to light absorbing compounds.
• This limitation is overcome by post column
Derivatization

Gamal A. Hamid52
FL Principle
• FL is a phenomenon in which a substance absorbs light to reach a high-energy level and
then emits light to return to its original level.
Such a substance has specific wavelengths of light that it absorbs (excitation
wavelengths) and emits (emission wavelengths).
• While a UV/UV-VIS detector detects light that has passed through the flow cell, an FL
detector detects fluorescence emitted in the direction orthogonal to the exciting light.
• A UV/UV-VIS detector monitors the absorption of light with a specified wavelength.
However, some substances absorb light at one wavelength, and then emit light called
fluorescence at another wavelength.

Gamal A. Hamid53
FLD Features and highlights
Single wavelength: up to 200 Hz (FLD-3400RS)
Multiple wavelength: up to 4 Hz (FLD-3400RS)
Single wavelength: up to 100 Hz (FLD-3100).
• Light source:
High-intensity xenon flash lamp with smart
control features
• Flow cells:
8 μL analytical flow cell
2 μL micro flow cell.
Wavelength range 200 – 650 nm
Wavelength range 200 – 900 nm (dual).
• Long lamp life (> 15,000 h in long life
mode).
• Flow Cell temp:
Thermostatting: Ambient + 15 °C to 50 °C.
• Spectrum Scanning Modes:
2D or 3D excitation, emission
Up to 4 channels (FLD-3400RS)
1 channel (FLD-3100)

Gamal A. Hamid54
FL Detector Chromeleon page

Gamal A. Hamid55
Refracted index Detector
• The response is dependent on changes in refractive index of eluting
compounds in the mobile phase.
• The mobile phase itself should have refractive
index different from the sample.
• Gradient programming is not possible due to
resulting changes in refractive index of mobile phase.
• Temperature control is necessary as it has
high temperature sensitivity.
• Any component in the eluate can be detected;
thus, the RI detector is often called a “universal detector”.
• Typical applications are in Size Exclusion Chromatography.
• The detector is less sensitive than UV-VIS detector.

Gamal A. Hamid56
RI Principle
• RI detector detects components based on the
refraction of light in solution.
• The reference-side cell is filled with eluate, and the
column eluate is introduced into the sample-side
cell through the changed flow channel.
• When components are eluted from the column, the
chemical composition changes in the sample-side
solution, which changes its photorefractive level.
As a result, the amount of light received by the light-
receiving section changes, showing a peak which
can be detected.

Gamal A. Hamid57
FLD Features and highlights
Single wavelength: up to 200 Hz (FLD-3400RS)
Multiple wavelength: up to 4 Hz (FLD-3400RS)
Single wavelength: up to 100 Hz (FLD-3100).
• Light source:
High-intensity xenon flash lamp with smart
control features
• Flow cells:
8 μL analytical flow cell
2 μL micro flow cell.
Wavelength range 200 – 650 nm
Wavelength range 200 – 900 nm (dual).
• Long lamp life (> 15,000 h in long life
mode).
• Flow Cell temp:
Thermostatting: Ambient + 15 °C to 50 °C.
• Spectrum Scanning Modes:
2D or 3D excitation, emission
Up to 4 channels (FLD-3400RS)
1 channel (FLD-3100)

Gamal A. Hamid58
Corona Detector
• The Corona CAD detector provides the ability
to measure virtually any nonvolatile and
many semi volatile analytes:
• Positive, negative, or neutral, with or
without a chromophore, all can be detected
routinely with charged aerosol detection.
• The Corona CAD can readily detect
compounds present in single digit nano gram
quantities.
• Corona CAD’s unique method of detection
allows quantitation across a range that
exceeds four orders of magnitude

Gamal A. Hamid59
Corona principle
• The Corona CAD “Charged Aerosol
Detector “ measures charge that is
imparted to analyte particles, with the
charge being in direct proportion to the
amount of the analyte in the sample.
• Samples nebulized by air or nitrogen then
dried, dried particles combined with the
charged gas (charged using high voltage),
pass through the collector where the
charged particles are measured using
sensitive electrometer.

Gamal A. Hamid60
Corona Applications
• Pharmaceuticals
• Proteins
• Lipids
• Steroids
• Oligosaccharides
• Surfactants
• Carbohydrates
• Polymers
• Peptides
Corona CAD is appropriate for any nonvolatile and many semi volatile compounds,

Gamal A. Hamid61
Systems variations
Item Nano/Cap
Basic automated
/ Standard
RSLC
Pump Max. Pressure 800 bar 620 bar 1034 bar
Pump. Max. Flow 50 µL/min 10 mL/min
5 mL/min @ 1034
bar
8 mL/min @ 800 bar
Autosampler Max. pressure 1000 bar 620 bar 1034 bar
Column Oven Max.
Temperature
80 °C
50 oC (Basic)
80 °C (Standard)
110 °C
Column Oven Max
pressure
1000 bar 620 bar 1034 bar
Detector Data Collection
Rate
200 Hz* 100 Hz 200 Hz*

Gamal A. Hamid63
Fit the system to the applications
The UltiMate 3000 systems are fully modular, allowing you to choose common system
configurations or design the most suitable system for your application needs.

Gamal A. Hamid64
Applications fields
• Environmental applications
• Food applications
• Pharmaceutical applications
• Bioanalytical applications
• Pharmaceuticals like aspirin, ibuprofen, or acetaminophen (Tylenol)
• Salts like sodium chloride and potassium phosphate
• Proteins like egg white or blood protein
• Organic chemicals like polymers (e.g. polystyrene, polyethylene)
• Heavy hydrocarbons like asphalt or motor oil
• Many natural products such as ginseng, herbal medicines, plant extracts
• Thermally unstable compounds such as trinitrotoluene (TNT), enzymes

Gamal A. Hamid66
Carbohydrates Analysis
https://tools.thermofisher.com/content/sfs/brochures/AI-71469-Chromatography-Foods-Beverages-Carbohydrates-AI71469-EN.pdf

Gamal A. Hamid67
Sugar Substitutes
http://tools.thermofisher.com/content/sfs/brochures/AI71470-Chromatography-Foods-Beverages-Sugar-Substitutes-AI71470-EN.pdf

Gamal A. Hamid68
Fats and Oils Analysis
https://tools.thermofisher.com/content/sfs/brochures/AI-71471-Chromatography-Foods-Beverages-Fats-Oils-AI71471-EN.pdf

Gamal A. Hamid69
Flavors, Colorants and Additives
http://tools.thermofisher.com/content/sfs/brochures/AI-71472-Chromatography-Foods-Beverages-Flavors-Colorants-Additives-AI71472-
EN.pdf

Gamal A. Hamid70
Supplements Analysis
http://tools.thermofisher.com/content/sfs/brochures/AI-71473-Chromatography-Foods-Beverages-Supplements-AI71473-
EN.pdf

Gamal A. Hamid71
Profiling Beverages
https://tools.thermofisher.com/content/sfs/brochures/AI-71474-Chromatography-Profiling-Beverages-AI71474-EN.pdf

Gamal A. Hamid72
Adulteration and Authentication
https://tools.thermofisher.com/content/sfs/brochures/AI-71475-Chromatography-Foods-Beverages-Adulteration-Authentication-
Applications-Notebook-AI71475-EN.pdf

Gamal A. Hamid73
Contaminants
http://tools.thermofisher.com/content/sfs/brochures/AI-71476-Chromatography-Foods-Beverages-Contaminants-Applications-
Notebook-71476-EN.pdf

Gamal A. Hamid74
Antifoaming Agents, Emulsifiers and Surfactants
http://tools.thermofisher.com/content/sfs/brochures/AI-71477-Chromatography-Foods-Beverages-Antifoaming-Emulsifiers-
Surfactants-AI71477-EN%201214S.pdf

Gamal A. Hamid75
Vitamin and Antioxidant
https://tools.thermofisher.com/content/sfs/brochures/AI-71478-Chromatography-Foods-Beverages-Vitamins-Antioxidants-
AI71478-EN.pdf

Gamal A. Hamid76
Visit thermoscientific.com/AppsLab
• Access GC, IC, LC, GC-MS, and LC-MS application notes in a single online location.
• Download one-click workflows: immediately ready to run in Chromeleon CDS.
• Compare results and identify optimum chromatographic separation conditions quickly
and easily.
• Visible to all users. Register once for free and download complete separation methods.
https://appslab.thermofisher.com/

HPLC System Selection

Recommended

Recommended

More Related Content

What's hot

What's hot (20)

Similar to HPLC System Selection

Similar to HPLC System Selection (20)

More from Gamal Abdel Hamid

More from Gamal Abdel Hamid (20)

Recently uploaded

Recently uploaded (20)

HPLC System Selection