Running an efficient and productive lab requires having the right tools and solutions in place. One of the most critical aspects of any lab is chromatography, which allows for the separation, identification and purification of chemical compounds. Using the optimal chromatography consumables and solutions can significantly enhance your lab's operations and output.

In this guide, we'll explore key tips on how to optimize your lab workflow using chromatography consumables and solutions.

Ensure Proper Column Selection

The column is the core of any chromatography system, containing the stationary phase material that provides the separation mechanism.  Choosing the right column is imperative for achieving desired resolution and analysis times. There are many factors to consider when selecting columns for specific applications and throughput needs.

Match Stationary Phase to Analytes

The stationary phase is the heart of the column. For reversed phase LC, typical stationary phases are C18 or C8 bonded silica, with a nonpolar carbon chain ligand. For nonpolar analytes, longer C18 chains provide greater retention through hydrophobic interactions. Shorter C2, C4, and C8 phases are better for moderately polar compounds.

phenyl-hexyl or pentafluorophenyl (PFP) stationary phases use pi-pi interactions for separation of aromatics and planar molecules. Cyano (CN) or amino (NH2) phases operate through polar and dipole interactions, ideal for polar analytes in normal phase mode.

Ion exchange phases contain charged functional groups to retain analytes by ionic interactions. Reversed phase ion pair phases combine hydrophobic chains with ion pairing groups for enhanced retention of ionic compounds. Matching the stationary phase to the analyte properties ensures optimal selectivity and separation.

Column Dimensions Affect Resolution

Column length, inner diameter (ID) and particle size interplay to determine separation efficiency. Longer columns provide more theoretical plates, allowing more opportunity for equilibration between mobile and stationary phases. More plates means better resolution, but longer retention times. Typical columns range from 50-300 mm long.

Smaller diameter columns offer better mass transfer and sensitivity for trace analysis, but limit sample capacity. Standard analytical columns are 4.6 mm ID. For higher throughput, 5-10 mm ID columns accommodate greater flow rates.

Smaller diameter stationary phase particles supply more surface area and theoretical plates. Sub-2 μm particles are common for ultrahigh pressure liquid chromatography (UHPLC) systems. But the smaller particles also create higher backpressure. Balance resolution needs with pressure constraints when selecting particle size.

Consider Analyte, Sample Properties

The composition and properties of the sample matrix factor into column selection. For samples with a wide range of analyte concentrations, choose a higher capacity column. Samples with high matrix interferences may require tandem columns or guard columns for protection. If trace analytes are present, opt for smaller ID columns to concentrate samples.

For LC, determine sample solubility to match stationary phase and mobile phase polarity. For GC, consider analyte volatility and thermal stability for oven temperature limits. In all cases, pH, chemical compatibility, and Select optimum column dimensions based on analyte characteristics and separation goals.

Balance Resolution and Throughput

Resolution requirements determine optimal length. For baseline resolution of closely eluting peaks, choose longer columns up to 300 mm. For faster analysis of well-resolved analytes, 50-100 mm columns suffice.

Diameter relates to sample capacity and throughput. Standard 4.6 mm ID columns accommodate routine flow rates of 1-2 mL/min. For rapid methods, 5-10 mm columns operate at 8-50 mL/min flow rates for ultrafast chromatography. Capillary GC columns are commonly 0.25-0.53 mm for optimal efficiency.

Particle size also balances resolution and speed. Sub-2 μm columns provide the highest plate counts and resolution but require specialized ultrahigh pressure systems. 3-5 μm particles are robust, reliable workhorses for most separations. Monolith columns offer fast flow through porous rods or billets for high throughput.

Consult experienced specialists like IT Tech to select columns with ideal dimensions for your needs.

Construction Materials Matter

The column hardware itself must be chemically and physically robust. LC columns use stainless steel, titanium, PEEK, or fused silica housings. GC column tubes are fused silica with polyimide protective coatings.

End fittings should provide leak-free, low dead volume connections. Common fittings are PEEK, titanium, or stainless steel. Integral end frits prevent stationary phase disturbance. Metal frits offer the best retention and durability. Column inlet filters help protect the column bed from particulates.

Stationary phase bonding should remain stable throughout method conditions and sample matrices. Silica gels support a wide range of bonded phases. Polymeric packings withstand more extreme pH. Zirconia phases tolerate aggressive organics.

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Use High-Quality Chromatography Supplies

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While instrumentation like pumps, detectors and data systems get much of the attention, chromatography success depends heavily on the quality of associated consumables and supplies. Vials, caps, syringe filters, sample loops, needles, tubing, fittings and more must all meet stringent requirements for inertness, consistency and purity. Overlooking consumables can undermine method robustness and data integrity. This guide explores criteria for optimal chromatography supplies.

Vial and Closure Quality Control Separation Outcomes

Autosampler vials contain the sample for injection, so surface treatments must prevent analyte absorption. Clear or amber glass resists most chemicals, while plastic vials can leach contaminants or retain analytes. Screw caps with PTFE-faced silicone septa form tight, uniform seals without shedding particles. Preslit PTFE-backed septa withstand repeated piercing without coring. Certified low particulate caps and consistent torque specifications ensure reproducibility.

Volume variability due to manufacturing tolerances in vials, caps and septa can directly impact precision and accuracy. Only purchase certified, pre-qualified consumables within strict dimensional specifications. Beware uncertified products with high variability. Properly filled vials also prevent problems like crashed solvent fronts or poor peak shape. Follow established fill volume guidelines.

Any impurities, residues or particulates from manufacturing processes can lead to extraneous peaks, ghosting, or elevated baseline noise. Insist on highest purity grades and clean room level environmental controls during production and packaging. Perform quality control extraction or “blank” tests to validate consumable inertness.

Rugged materials withstand injection, separation forces, and storage conditions. Amber glass protects photosensitive analytes from UV and ambient light exposure. Use reinforced vials and caps that can tolerate repeated mechanical stress. Leak-proof PTFE-lined septa maintain sample integrity even after 100s of injections.

IT Tech adheres to stringent QC, cleanroom assembly, and rigorous supplier audits so labs can rely on consumable performance.

Tubing Maintains Flow Path Integrity

The fluidic flow path tubing must convey mobile phases and samples without leaching, adsorption, or altering composition. Stainless steel offers exceptional chemical resistance and low gas permeability for stable gradients. However, stainless steel is prone to corrosion from salts or improper storage.

PEEK (polyetheretherketone) withstands a wide pH range and solvents like chlorinated organics. PTFE (polytetrafluoroethylene) tubing is highly chemically resistant and minimizes peak tailing, but requires careful handling to avoid kinks. Take care to optimize inner diameters (IDs) for proper system flows and dispersion.

Ferrules form critical tube-fitting junctions and should only be finger-tightened once to avoid leaks. Change ferrules with every tubing cut to maintain a fresh seal. Inspect fittings regularly for degradation and replace at the first sign of wear. Proper tubing care is essential for consistent, uninterrupted sample delivery to columns and detectors.

IT Tech stocks a broad selection of chromatographic tubing designed for every LC and GC application need. Our technical experts can recommend ideal materials and dimensions.

Sample Prep Consumables Guard Analyte Integrity

Syringe filters, solid phase extraction (SPE) products, and sample vials constitute the first line of protection for analytes prior to injection and separation. 0.2-0.45 μm pore PTFE, nylon, or PES syringe filter units remove particulates to prevent column plugging and distortion.

SPE sorbents like C18, silica, ion exchange, or immunoaffinity in cartridges, discs, or 96-well plates concentrate trace analytes and remove interferences. Collection plates and appropriate elution solvents complete SPE workflows.

Autosampler vials, certified free of plasticizers or metals, along with screw caps and septa certified for 100s of injections maintain sample integrity throughout analysis sequences. Only use consumables qualified for sample storage conditions like ultra-low temperature or accelerated stability protocols.

Trust IT Tech’s extensive selection of the highest purity sample handling products to safeguard analytes during every preparatory step leading to chromatographic analysis.

Detection Cells Warrant Scrutiny

Flow cells or cuvettes installed in UV, fluorescence, or other detectors must transmit light consistently across the measurement pathway without adding background interference. Precision bore tubes constructed of optical grade quartz, glass, or plastic polymers minimize measureable variability. reflective coating. Bioinert surface treatments prevent analyte adhesion. Path lengths range from standard 10 mm to micro-volume cells under 2 μL. Proper flow cell selection reduces baseline noise and protects detector lamp life.

For mass spectrometry (MS) interfaces, only use consumables rated for the ionization source. Avoid surface treatments and materials that outgas. Nebulizer assemblies, heaters, lenses and o-rings must withstand solvent exposure and ionization conditions. Change MS consumables regularly to maintain optimal ion transmission and detection.

With expert guidance from IT Tech, labs can identify and implement robust, reliable chromatography supplies for sensitive detection and quantification.

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Utilize Optimized Mobile Phases for Ideal Chromatography

HPLC and UHPLC Mobile Phases

For high performance liquid chromatography (HPLC or UHPLC), the mobile phase is composed of solvents and additives. Typical starting points are:

• 60-95% aqueous component – This provides the polar component. Deionized HPLC grade water is ideal. Buffers or ion pairing additives are commonly added to the aqueous solvent.
• 5-40% organic modifier – The weak solvent component, usually acetonitrile or methanol. Increases elution strength.

For reversed phase methods, the organic component is increased over time in a gradient to elute retained analytes. Additives like acids, bases, or salts manipulate analyte ionization.

Mobile Phase Purification

Impure solvents introduce contaminants and ghost peaks. Always use HPLC grade or better solvents, free of stabilizers and residue. Further purification steps include:

• Degassing – Dissolved gases absorb strongly in the UV range and cause noise. Remove gases by vacuum filtration, sonication, or helium sparging.
• Microfiltration – Use 0.2 μm membrane filters to remove particulates. Change filters when flow rates drop.
• Vacuum distillation – Distillation provides the highest purity by removing trace impurities.
• Solvent scrubbing – Percolating through beds of activated carbon and molecular sieves.

Prepared mobile phases also require degassing and filtration before use. Inline solvent degassers and filters protect systems.

Miscibility and Solubility

The organic and aqueous solvents must be miscible over the full range of gradient concentrations. Solvents like acetonitrile and methanol are compatible with most additives. Ensure additives like ion pairing agents are soluble over the range of mobile phase pH and percent organic before use. Insoluble precipitates can irreparably foul columns.

Ideal Mobile Phase pH

For ionizable analytes, adjust aqueous buffer pH to promote ionization or protonation. This alters retention. Lower pH protonates bases, increasing hydrophobicity and retention on reversed phase columns. Higher pH ionizes acids, reducing retention. Optimize pH for selectivity and separation.

Component Compatibility

Not all solvents, buffers, and additives that are individually suitable are necessarily compatible. Combining phosphoric acid and acetate or formate buffers can lead to phosphate precipitation. Amines react with aldehydes. Test mixed mobile phases for physical compatibility before use.

Proper mobile phase optimization improves peak shape, sensitivity, and resolution. The experts at IT Tech can recommend ideal solvents, buffers, and additives.

Gas Chromatography Mobile Phases

In gas chromatography (GC), the mobile phase is an inert carrier gas, typically:

• Helium - Most common, provides optimal flow properties.
• Hydrogen - Higher optimum linear velocities, requires special safety.
• Nitrogen - Most cost effective, higher viscosity impacts efficiency.

Flow rate and gas velocity impact separation. Typical linear velocity through the column ranges from 20-40 cm/second. Temperature programming offsets viscosity changes.

GC Column Considerations

The nature of the stationary phase coating determines optimum carrier gas velocity for elution. Polar stationary phases call for slower flow to allow time for interactions. Small ID capillary columns require slower linear velocity for optimum performance.

For splitless injection techniques, higher initial velocities give sharper peaks. But higher velocities reduce column efficiency and resolution. Balancing sensitivity and resolution determines velocity.

Work with IT Tech GC experts to optimize mobile phase flow rates and temperature programs. Proper method development maximizes resolution and peak shape.

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Employ Effective Sample Preparation to Optimize Chromatography

While instrumentation defines separation power, sample preparation is equally crucial for reliable, meaningful results. No matter how advanced the chromatography system, poorly prepared samples lead to dirty baselines, precision issues, matrix effects, and inaccurate data. The goal of sample prep is to obtain analytes in a form ideal for analysis – representative, interference-free solutions matching the method’s mobile phase composition. This requires careful planning, robust techniques, and quality consumables.

Understand the Sample Matrix

The first step is understanding the sample matrix and its impact on analysis. Complex matrices like plasma, soil or food contain diverse interferences that must be removed. Target analyte concentrations and the presence of co-eluting isomers influence preparation steps. Sample solubility must match the separation mode – polar for normal phase or non-polar for reversed phase.

Record details like pH, salt content, viscosity, particulate levels, and the tendency for foaming or precipitation. Watch for changes upon standing like settling. These details guide the path to an optimal sample solution. For difficult matrices, prepare matrix-matched standards.

Remove Interferences

Centrifuging or allowing samples to settle removes many particulates, but finer techniques are required to isolate target analytes from interferences.

Liquid-Liquid Extraction (LLE) partitions analytes selectively between immiscible liquids. Adding an organic solvent like ethyl acetate or dichloromethane to an aqueous sample pulls out analytes based on relative solubility. Multiple extractions maximize recovery.

Solid Phase Extraction (SPE) uses cartridges packed with sorbents like C18, ion exchange media, silica, or immunoaffinity particles. Samples pass through, allowing analytes of interest to be retained while interferences flow to waste. An elution solvent then liberates purified analytes from the sorbent bed for analysis. SPE streamlines sample cleanup.

Protein Precipitation crashes proteins out of solution through a reagent like acid or organic solvent. The clarified supernatant can then be injected.

For suspended samples, gravity filtration alone may suffice, but membrane syringe filters are essential final steps.

Remove Particulates

Filtration should be the final step to clarify samples and prevent column or instrument damage. Glass wool filters work for relatively clean samples. Membrane syringe filters with 0.45 – 0.2 μm pore sizes trap finer particulates. Nylon and PTFE (Teflon) membrane materials resist sample interaction. Centrifuging at high G forces can also clear finer particulates.

Inspect filters before and after use – discarded ones should show particulates indicating effective filtration. Clogged membranes lead to distorted peaks. Always filter mobile phases as well, including individual solvent components and prepared mixtures. Inline solvent filters help protect systems.

Concentrate Dilute Samples

Trace analytes can escape detection without some form of concentration or enrichment.

SPE selectively retains dilute analytes then elutes in a smaller volume to boost quantitation.

Solid Phase Microextraction (SPME) uses coated fiber probes to concentrate vapors or headspace samples before GC analysis.

Liquid-Liquid Extraction introduces a concentration factor by dissolving analytes into a smaller volume of organic solvent.

Evaporation under nitrogen stream or in a centrifugal vacuum concentrator followed by reconstitution gives a substantial concentration boost. However, take care to avoid excess evaporation.

For GC analysis, analytes must be made sufficiently volatile. Chemical derivatization with MTBSTFA, BSTFA, PtFB-Br or similar agents appends reactive groups onto compounds to make them more volatile and less polar for enhanced chromatographic response.

Ensure Analyte Stability

From extraction through analysis, keep samples within required temperature limits. Use chilled reagents for labile analytes. Avoid excessive illumination for photosensitive compounds. Use stabilized solvents like phosphoric acid to prevent decarboxylation. Adjust sample pH to 7 if acidic or basic conditions degrade analytes.

If denaturation is still a risk, add reagents like ascorbic acid to quench free radicals or EDTA to bind metals that catalyze reactions. Spike isotopically-labeled internal standards early to monitor analyte integrity through the full sample path.

Meet Method Requirements

The final step adjusts samples to match chromatography method conditions through dilution, pH adjustment, etc. Always prepare an extraction or reconstitution solvent that matches the starting mobile phase composition. Confirm sample solubility – precipitates can irreparably foul columns. Introduce any ion pairing agents or modifiers used in the method. Perform trial injections to verify analyte stability and check for coelutions or interferences. Iterate adjustments until satisfied.

With attention to detail and quality consumables, sample solutions entering the chromatography system will be clean, consistent, and set up for success. IT Tech provides all the products needed to streamline preparation and optimize analysis results.

Liquid-Liquid Extraction Essentials

Also called solvent extraction, LLE dissolves analytes of interest into an immiscible organic solvent, separating them from an aqueous sample matrix. Common organic solvents include:

• Hexane – Nonpolar solvent ideal for nonpolar analytes.
• Diethyl ether – Polar solvent suitable for polar organics.
• Dichloromethane – Extracts broad range of moderately polar analytes.
• Ethyl acetate – Used for acids, bases, and moderates.
• Chloroform – Once widely used, but restricted today due to toxicity.

LLE procedures involve:

• Mixing samples and solvents in a separatory funnel.
• Agitating or shaking vigorously to facilitate transfer.
• Allowing phases to separate.
• Drawing off the solvent layer containing purified analytes.
• Repeating extractions to improve recovery.
• Concentrating extracts by evaporating excess solvent.
• Using pH adjustment to selectively ionize analytes into one phase.

With proper solvent selection and execution, LLE removes interferences and concentrates analytes prior to analysis.

SPE Strategies for Sample Cleanup

Solid phase extraction (SPE) streamlines sample preparation through selective retention of analytes on sorbent particles. Key steps include:

• Condition cartridge with an appropriate solvent
• Load sample, allowing analytes to adsorb while interferences pass through
• Rinse to remove remaining interferences
• Elute analytes using a solvent that displaces them from the sorbent
• Dry and reconstitute eluate

Sorbents choices for SPE include:

• C18 – Retains nonpolar to moderately polar organics
• Silica – Used for normal phase applications
• Ion exchange – Anion or cation exchangers retain charged analytes
• Immunoaffinity – Antibodies provide selective extraction
• Graphitized carbon – Useful for pigmented, DNA, drug, and food samples

Proper sorbent selection and method development lead to purified, concentrated analytes ideal for chromatography.

Derivatization for GC Analysis

Gas chromatography (GC) requires analytes that are thermally stable and sufficiently volatile. Polar, nonvolatile compounds are common challenges. Derivatization via silylation or alkylation appends groups that increase volatility and reduce polarity. Common derivatization reagents include:

• BSTFA (N,O-bis-trimethylsilyltrifluoroacetamide) – Silyates alcohols, phenols, thiols, amines
• MTBSTFA (N-methyl-N-tert-butyldimethylsilyltrifluoroacetamide) – Alternative to BSTFA, better stability
• TMCS (trimethylchlorosilane) – Used with BSTFA for sterically hindered groups
• TMSI (N-trimethylsilylimidazole) – More reactive than BSTFA, good for sterically hindered amines
• PFBBr (pentafluorobenzyl bromide) – Alkylates carboxyl, hydroxyls, amines, adds electron density

Proper derivatization procedures are key to generating stable, volatile derivatives amenable to GC analysis.

Quenchers and Protectants

Some analytes are prone to degradation during extraction or analysis procedures. Quenching agents and stabilizers can be added to samples to improve integrity:

• Ascorbic acid – Free radical scavenger, prevents oxidative degradation reactions
• Oxalic acid – Quenches nitrosating agents that can alter analytes
• EDTA – Chelator binds metals that catalyze hydrolysis, oxidation reactions
• Ethanol – Stabilizes labile analytes and can also precipitate proteins
• Phosphoric acid – Prevents decarboxylation reactions

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Optimize Chromatography Through Proper System Care and Maintenance

‍Chromatography (HPLC), gas chromatography (GC) and mass spectrometry (MS) systems represent major investments for analytical laboratories. Keeping these sensitive instruments operating in peak condition necessitates rigorous care and maintenance. Preventive procedures maximize uptime, deliver reliable results, extend equipment lifespan and avoid costly downtime. This guide covers essential practices for system care.

Importance of Maintenance

Complex chromatographic modules contain precision pumps, injectors, columns, tubing, detectors and data systems, each requiring specialized upkeep. Failure to follow prescribed procedures risks:

• Leaks, blockages or contamination that disrupt flow
• Declining analytical performance as components degrade
• Erratic retention times, ghost peaks, and erroneous data
• Permanent damage to expensive system elements

Dedicated maintenance activities keep all aspects properly cleaned, inspected, adjusted and replaced. Treat your instrumentation with care for lasting value.

Sample and Mobile Phase Filtration

Particulate matter causes extensive problems by clogging tubing, fouling injectors, plugging columns, and coating detector flow cells. Always filter:

• All solvents and reagents before adding to the mobile phase
• Combined mobile phases after mixing but before use
• Samples prior to injection through 0.45 or 0.2 μm syringe filters

Replace in-line solvent filters when the pressure drop exceeds limits. Record and log all filter changes. Rigorously filtering protects chromatography systems.

Column Care Essentials

The analytical column is the heart of any chromatography system. Key aspects of care include:

• Meticulous sample filtration to prevent particulates from entering the column
• Using guard columns and guard cartridges to trap contaminants
• Keeping columns installed or stored properly to prevent drying out
• Backflushing columns regularly with appropriate solvents to remove strongly retained materials
• Tracking the number of injections on a column to watch for performance declines
• Monitoring pressure changes over time as an indicator of column health

Vigilant column care prolongs column life, separates more samples, and avoids distortion or loss of resolution.

Tubing Maintenance

The fluidic tubing pathways must convey mobile phases without leaking, precipitating salts, or allowing analyte adsorption. Care guidelines:

• Truncate any degraded, cracked or deformed sections
• Make clean square cuts to optimize connections
• Replace ferrules with each new installation
• Finger tighten fittings properly without overtightening
• Use minimal lengths of tubing to limit dispersion
• Inspect for proper o-ring seating and wear

Proactively replacing worn tubing and fittings prevents costly mid-sequence leaks and shutdowns.

Injection System Integrity

The sample injection area undergoes constant mechanical stress and chemical exposure. Inspect key aspects:

• Autosampler needle sharpness and sample contact points
• Sample loop cleanliness and integrity
• Septum wear and potential coring – replace routinely
• Septum purge effectiveness in preventing contamination
• Injection port liner condition after extensive sample exposure

Maintaining optimized injection systems gives reliable sample volumes and better chromatography.

Detector Maintenance

Specialized detector modules like UV-Vis, PDA, fluorescence and RI have components requiring care:

• Lamp age and hours tracked against expected lifetime
• Flow cell cleanliness and precision bore tubing condition
• Reference cell fluid condition and level
• Tubing or cable connections free of kinks and damage
• Reflective surfaces cleaned and proper alignment maintained

Following prescribed detector maintenance preserves sensitivity and calibration.

Data System Precautions

Closely monitor chromatography data systems:

• Audit trail of data back-ups, software updates, and events
• System access control and settings protected
• Log files checked for faults or errors
• Review permissions and user accounts regularly

Proper data system precautions maintain data integrity and continuity.

Gas Chromatograph Care

Gas chromatographs also require specialized maintenance for peak performance:

• Column installation and conditioning protocols followed
• Injection port septum and liner condition optimized
• Detector cleaning including flame photometric detectors
• Leak checks for carrier gas lines
• Temperature verification and gas flow calibration
• General housekeeping - vent line traps, dust removal, etc.

Proper GC care results in sensitive, stable quantitative analysis.

LC and LC/MS Maintenance

Liquid chromatography and mass spec systems have additional care needs:

• Pump seal wash protocols and seal replacement schedule
• Solvent degassing unit maintenance
• APCI probe, ESI needle, and ion volume cleaning
• Quad and ion trap cleaning and calibration
• Foreline and rough pump oil changes
• Manifold and gas generator supply maintenance

Robust LC/MS maintenance maximizes uptime and ion transmission.

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Enhance Chromatography Capabilities with Specialized Accessories

[Image description: A fraction collector with a collection plate and test tubes collecting separated analyte fractions.]

Image caption: A fraction collector with collection plate and test tubes

Image alt text: Fraction collector with collection rack and tubes

While the core components of pumps, injectors, columns and detectors enable high performance liquid chromatography (HPLC) and gas chromatography (GC), specialized accessories expand functionality, throughput and flexibility. From autosamplers to switching valves, column heaters to fraction collectors, advanced add-ons overcome limitations to meet developing analysis needs. This guide explores key accessories that extend chromatography powers.

Autosamplers Boost Productivity

Manual injection is tedious and ties up valuable operator time. Autosamplers automate the injection process for unlimited unattended sample analysis. Both GC and LC autosamplers include:

• Sample trays or racks with capacity from 40 to 150+ vials
• Precision syringe and plunger to draw and deliver fixed sample volumes
• Automated arm to transfer samples from vials into the injector
• Cooling and heating to maintain sample integrity
• Customizable injection sequences of multiple samples

By removing sample handling errors and allowing around-the-clock operation, autosamplers radically improve laboratory productivity and efficiency.

Fraction Collectors for Comprehensive Analysis

Fraction collectors allow isolating multiple fractions from a single sample injection for further analysis or processing. This enables:

• Collecting purified target analytes
• Performing multiple tests on individual fractions
• Identifying unknown peaks through additional testing
• Two-dimensional chromatography by analyzing fractions on a second column

Both LC and GC fraction collectors automatically deposit eluting peaks into vials, plates or tubes according to threshold and timing criteria. Advanced models support multifraction analysis.

Column Heaters Improve Separations

Column heating systems allow active control of the analytical column temperature during a run, unlike column ovens which maintain a static temperature. Benefits include:

• Improved resolution for difficult separations
• Variable temperatures to customize selectivity
• Focused narrow peaks at higher temperatures
• Reduced pressure in LC columns
• Wider range of linear velocities for GC

Heated columns expand possibilities for method development and optimization.

Guard Columns Protect and Extend Column Life

Analytical columns represent significant investments and their lifetimes are impacted by sample contaminants. Guard columns serve as sacrificial pre-columns to protect expensive analytical column beds. They trap:

• Particulates that escape filtration
• Non-eluted materials like proteins or lipids
• Strongly retaining compounds that irreversibly absorb

Guard columns concentrate damage before the analytical column through an inexpensive form of insurance. They are replaced more frequently, preserving resolution and column life.

Switching Valves Provide Versatility

Switching valves expand the possibilities for fraction analysis, backflushing, heart-cutting, column switching and multi-dimensional chromatography. Valve capabilities include:

• Diverting fractions to collection vials or a second column
• Backflushing columns to remove strongly retained materials
• Enabling tandem column confirmation workflows
• Alternating between multiple columns
• Configuring 2D GCxGC or LCxLC systems

Switching valves extend chromatographic flexibility. Consult IT Tech experts to leverage valves for your application.

Adopt Advanced Chromatography Techniques for Greater Resolution

Chromatography is constantly evolving, with new separation modes, column technologies, instrumentation and hyphenated techniques. Upgrading to the latest advancements allows labs to take on more challenging analytes, complex matrices, and lower detection levels. This guide explores cutting edge techniques to consider.

Ultrahigh Pressure Liquid Chromatography

Ultrahigh pressure liquid chromatography (UHPLC) systems generate pressures up to 120 MPa, allowing use of smaller particle size columns. Benefits include:

• Smaller particles pack tightly to provide more theoretical plates
• More plates give markedly higher resolution, separating closely eluting or trace analytes
• Van Deemter curves favor smaller particles at higher linear velocities
• Narrower peaks boost signal intensity, improving detection

Specialized UHPLC instruments use smaller ID columns for efficiency along with 1.5 μm or sub-2 μm particles for separations impossible by conventional HPLC.

Efficient Core-Shell Column Technology

Core-shell or fused-core particle columns combine a solid silica core with a porous outer shell, drawing benefits from both. Advantages include:

• Solid core adds mechanical stability to withstand ultrahigh pressures
• Porous shell provides surface area for sample interactions
• Thinner shell diffusion paths accelerate mass transfer
• 2.6 μm cores equal 1.7 μm totally porous performance
• Operate at lower backpressures than sub-2 μm porous particles

Core-shell provides high efficiency with excellent mechanical stability.

Monolithic Column Chemistry

Monolithic columns are a single continuous bed rather than packed particles. Sample flows through larger pores, improving mass transfer. Benefits include:

• Easy movement into micropores gives high permeability
• Rapid diffusion kinetics provide very fast separations
• High porosity allows use of particulate-based monoliths
• Can be molded into thin reporting layers for microfluidic devices

Monoliths separate faster at lower pressures but currently have limitations on application range.

Comprehensive Two-Dimensional Chromatography

Two-dimensional chromatography (2D-LC or GCxGC) runs samples through two columns with orthogonal separation modes for much higher peak capacity. Techniques include:

• Heart-cutting to transfer selected fractions from the first to second column
• Comprehensive sampling of the entire first column effluent into the second dimension
• Two-dimensional separation by polarity, molecular size, volatility, etc.
• Significantly enhanced ability to resolve and identify trace analytes

Hyphenated 2D systems provide far greater separation power.

Additional Advanced Approaches

Further techniques to consider include:

• Serial columns to amplify selectivity
• Selective detectors like ELSD for non-UV absorbing analytes
• Multi-mode chromatography using size exclusion, ion exchange, etc.
• Microfluidic and nano-scale columns and instrumentation
• Portable and field-deployable analysis options

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Leverage Chromatography Solutions from IT Tech

Optimizing your lab chromatography workflow is easier with the right partner. IT Tech offers a complete range of consumables, equipment, and services:

• The widest selection of top tier chromatography columns for any application.
• High purity solvents, reagents, vials, and accessories in consistent, reliable supply.
• Sophisticated LC/GC systems, detectors, and data systems for every lab.
• Experienced service technicians for installation, maintenance, and repair.
• Knowledgeable technical support and method development assistance.
• Custom kits, bundles, and bulk discounts to simplify procurement.

Bring your toughest chromatography challenges to IT Tech. Our solutions will have your lab operating at peak efficiency. Submit an inquiry today to learn more about our specialized chromatography offerings.