We are pleased to invite you to our upcoming free online webinar on June 11, 2026 focused on one of the most pressing challenges in environmental monitoring and water quality management — PFAS (Per- and Polyfluoroalkyl Substances).As regulatory frameworks continue to evolve and compliance deadlines approach, laboratories, water utilities, and environmental professionals need robust, reliable, and cutting-edge analytical solutions to stay ahead.<blockquote>👉<a target="_blank" rel="noopener noreferrer" href="https://events.teams.microsoft.com/event/91d97003-fe33-4dca-b80b-160d9f8a5655@485ca04e-6f74-4050-9764-cdb4bfa89c25">Registration HERE</a></blockquote><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/ALS_analyzy_PFAS_a9e4a87fbc.jpg" alt="ALS: Advanced PFAS Analytical Services " srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_ALS_analyzy_PFAS_a9e4a87fbc.jpg 245w," sizes="100vw" width="600" height="336"><h4>🎤 Our Speaker</h4>The webinar will be hosted by Jana Kováčová, Ph.D., PFAS Regional Lead for Continental Europe Environmental Division, who has dedicated the last several years to the field of PFAS analysis and determination in ALS laboratories. Jana is a recognized expert in PFAS environmental analytics and will share practical insights and the latest developments in analytical strategies to help your organization achieve and maintain compliance.<h4>🎯 What You Will Learn</h4><ul><li>Latest regulatory developments and compliance requirements for PFAS in water, including EU Drinking Water Directive 2020/2184 and its implications for water suppliers and laboratories.</li><li>Regulatory updates for surface water and groundwater — what's new and what to expect next.</li><li>Overview of advanced analytical strategies for PFAS detection and quantification in water matrices and how we analyse PFAS samples.</li><li>Key analytical challenges associated with PFAS testing — from ultra-trace detection to matrix interferences and contamination control.</li><li>The critical importance of using tested sampling containers and sample preservation to ensure reliable results.</li><li>Illustrative examples of results from real-world PFAS water analyses.</li><li>How ALS can support your needs with accredited PFAS testing services.</li></ul><h4>👥 Who Should Attend</h4>This webinar is designed for our clients, professionals, laboratory and technical staff, scientists, as well as anyone with an interest in analytical chemistry who wants to better understand the occurrence of these "forever chemicals" in the environment. &nbsp;<h4>💬 Q&amp;A Session</h4>There will be a live Q&amp;A session at the end of the webinar. You are welcome to submit your questions in advance during registration or ask them live on the day.<h4>📅 Additional Webinar Info:</h4><ul><li>Platform: Microsoft Teams (online)</li><li>Time: 10:00 CEST</li><li>Language: English</li><li>Duration: approx. 45 - 60 minutes (incl. Q&amp;A) Extras: If you are unable to attend on the day, please register and we will provide you with the recording of the webinar.</li></ul><h4>🔬 About ALS Environmental</h4>ALS is a global leader in environmental testing and analytical services, providing accredited PFAS analysis to clients across Europe and beyond. Our dedicated PFAS experts help clients navigate the complex regulatory landscape with confidence.<blockquote>For further information, please contact us on: marketing.cz@alsglobal.com</blockquote>We look forward to welcoming you to this important discussion on PFAS compliance in water.

Invitation to the ALS Webinar PFAS in Water 2026: Achieving Compliance through Advanced Analytical Strategies

In HPLC and other chromatographic techniques, the quality of your analytical results depends heavily on the condition of the sample before it ever reaches the instrument. While vial caps may appear to be a small accessory, they play a critical role in maintaining sample integrity, preventing contamination, and minimizing evaporation.Whether you use crimp, screw, or snap caps, each closure type offers distinct advantages and limitations. Selecting the right option can improve sample protection, simplify laboratory operations, and help ensure consistent analytical performance. Let's take a closer look at the characteristics of each cap style and explore when each one is most appropriate.<h3>Sealing Performance: Protecting Your Sample</h3>The primary purpose of any vial cap is to create a reliable seal. However, different cap designs achieve this in different ways, resulting in varying levels of protection against evaporation, contamination, and sample degradation.<h5>Crimp Caps</h5>Crimp caps provide the highest level of sealing performance. A metal cap is mechanically crimped around the vial neck, creating a secure and highly airtight closure. This design minimizes sample loss and offers excellent protection during long-term storage.<ul><li>Ideal applications: When volatile compounds must be preserved, or when even minor contamination and evaporation cannot be tolerated, such as headspace analysis and highly sensitive analytical methods.</li></ul><h5>Screw Caps</h5>Screw caps are widely used because they combine practicality with dependable sealing. Their threaded design allows them to be tightened easily while still providing sufficient protection for the majority of HPLC applications.One of their biggest advantages is the ability to open and reseal the vial multiple times without requiring additional equipment.<ul><li>Ideal applications: Routine laboratory analyses, methods requiring repeated sample access, and workflows where convenience is important.</li></ul><h5>Snap Caps</h5>Snap caps emphasize speed and ease of use. They are pressed onto the vial until they lock into position with a simple click.Although they do not provide the same degree of airtight sealing as crimp or screw caps, they offer a fast and straightforward solution for many applications.<ul><li>Ideal applications: Short-term sample storage, stable analytes, and high-throughput environments where rapid handling is a priority.</li></ul><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/KNAUER_Crimp_vs_Screw_Caps_04bdfdd4a5.jpg" alt="KNAUER: Crimp and Screw Caps" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_KNAUER_Crimp_vs_Screw_Caps_04bdfdd4a5.jpg 245w," sizes="100vw" width="1152" height="389"><h3>Ease of Use: Supporting Laboratory Efficiency</h3>In busy analytical laboratories, workflow efficiency matters. The choice of vial closure can significantly affect the amount of time spent preparing samples.<h5>Crimp Caps</h5><ul><li>Advantages: Crimp caps deliver highly reproducible sealing when applied correctly. Automated crimping devices can further improve consistency while reducing operator-to-operator variability.</li><li>Limitations: A crimping tool is required for installation. Manual crimping can be labor-intensive and may produce inconsistent results if the technique is not properly controlled. In addition, removing a crimp cap typically damages it, requiring replacement before the vial can be resealed.</li></ul><h5>Screw Caps</h5><ul><li>Advantages: Screw caps are exceptionally user-friendly. They can be installed and removed without any specialized tools, making them convenient for workflows involving repeated sample access.</li><li>Limitations: Seal quality depends on proper tightening. Excessive torque can damage the cap or septum, while insufficient tightening may compromise the seal. Repeated opening and closing can also gradually wear the cap components.</li></ul><h5>Snap Caps</h5><ul><li>Advantages: Snap caps offer the fastest sealing process. Simply pressing the cap into position is sufficient, making them attractive for laboratories processing large numbers of samples.</li><li>Limitations: Their convenience comes at the expense of sealing performance. They provide less protection against contamination and solvent loss, particularly when handling volatile compounds.</li></ul><h3>Instrument Compatibility: Matching Caps to Your Workflow</h3>Selecting a vial cap is not only about sealing efficiency. Compatibility with vials, autosamplers, and laboratory procedures is equally important.<h5>Crimp Caps</h5><ul><li>Compatibility: Crimp caps are designed specifically for crimp-top vials and are commonly used in automated analytical systems. They work particularly well with glass vials and provide highly reliable sealing performance.</li><li>Limitations: The need for a crimping device introduces an additional workflow step. Furthermore, improper crimping—whether too loose or too tight—can result in inconsistent sealing and potential sample integrity issues.</li></ul><h5>Screw Caps</h5><ul><li>Compatibility: Screw caps are among the most versatile closure options available. They are compatible with many autosamplers and can be used with both glass and plastic vials.</li><li>Limitations: Although suitable for most routine analyses, they may not provide the level of sealing required for extremely volatile compounds or demanding headspace applications.</li></ul><h5>Snap Caps</h5><ul><li>Compatibility: Snap caps are intended for use with snap-ring vials. Many autosamplers that accommodate crimp or screw-top vials can also accept snap-ring formats, offering flexibility in certain laboratory environments.</li><li>Limitations: Their relatively loose seal makes them less suitable for long-term storage or volatile analytes. Before implementation, laboratories should verify autosampler compatibility with snap-ring vial formats.</li></ul><h3>How to Choose the Right Cap Type</h3>The best closure depends on the specific requirements of your application.<h4>Choose Crimp Caps When:</h4><ul><li>Your samples contain highly volatile compounds.</li><li>Long-term storage is required.</li><li>Maximum sealing performance is essential.</li><li>You are performing headspace GC or highly sensitive LC-MS/MS analyses.</li></ul><h4>Choose Screw Caps When:</h4><ul><li>Samples need to be accessed repeatedly.</li><li>Convenience and flexibility are important.</li><li>Compatibility across multiple instruments and workflows is required.</li><li>Standard HPLC applications are being performed.</li></ul><h4>Choose Snap Caps When:</h4><ul><li>Samples are relatively stable and non-volatile.</li><li>Fast sample preparation is critical.</li><li>High-throughput operations demand rapid vial handling.</li><li>Short-term storage is sufficient.</li></ul><h3>Final Thoughts</h3>Although vial caps are often overlooked, they can have a significant impact on both sample quality and laboratory productivity.To summarize:<ul><li>Crimp Caps: Provide the most secure and airtight seal, making them ideal for volatile compounds, sensitive analyses, and long-term storage.</li><li>Screw Caps: Offer an excellent balance between sealing performance and convenience, making them the preferred choice for many routine chromatographic applications.</li><li>Snap Caps: Deliver maximum speed and simplicity, making them well suited for stable samples and fast-paced laboratory workflows.</li></ul>By understanding the strengths and limitations of each cap type, laboratories can select the most appropriate closure for their analytical requirements, ensuring sample integrity while maintaining an efficient workflow.<blockquote>If you want to protect your samples and improve your HPLC’s performance, check out our brand-new <a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/products/2381">KNAUER originals HPLC Vials</a></blockquote>

Crimp vs. Screw Caps: Which is Better for Chromatography?

News from LabRulezLCMS Library - Week 24, 2026

Article

Product

Webinars

Application

Video

Poster

Water

For more than 40 years, ALS has provided testing and technical solutions to clients all over the world in a wide range of industries. We have built our global reputation by embracing the latest technologies and innovative methodologies to deliver high quality testing services to clients. ALS is able to leverage a multifaceted international team while remaining agile enough to provide local expertise and personalized solutions to every one of our clients.

ALS Czech Republic

Everything from the world of analytical chemistry in one place. We connect people in solving their problems. At Labrulez you will find all the necessary information easily, quickly and clearly. Stop searching and start finding.

LabRulez

Based in Berlin, KNAUER is a medium-sized, owner-managed company that has been serving the sciences since 1962. We develop and manufacture scientific instruments of superior quality for liquid chromatography, including: Analytical HPLC/UHPLC, Preparative HPLC, Fast protein liquid chromatography (FPLC), Multi-column chromatography/Simulated moving bed (SMB) chromatography. High pressure dosing, in-line detection systems, and osmometry are additional business areas.

KNAUER

KNAUER AZURA DAD 2.1L Diode Array Detector

KNAUER AZURA® DAD 2.1L is a high-performance diode array detector for HPLC/UHPLC featuring 190–700 nm coverage, LightGuide technology, low drift, and up to 100 Hz data acquisition.

The KNAUER AZURA® DAD 2.1L is a high-performance diode array detector designed for analytical, semi-preparative, and preparative liquid chromatography applications. Combining advanced optical technology, excellent sensitivity, and intuitive operation, the detector offers an affordable solution for demanding HPLC and UHPLC workflows.The detector features a newly developed optical system and intelligent temperature management that ensure maximum sensitivity while minimizing baseline drift. Optional LightGuide flow cells based on total internal reflection technology maximize light throughput and minimize peak dispersion, resulting in superior signal-to-noise performance. An optional fiber-optic adapter allows physical separation of the flow cell from the detector, enhancing safety when handling hazardous, explosive, or toxic compounds.<h3>Key Features</h3><ul><li>High-performance diode array detector for HPLC and UHPLC</li><li>Wavelength range from 190 to 700 nm</li><li>256-diode array with 2 nm pixel pitch</li><li>Advanced optical system with optimized temperature management</li><li>LightGuide flow cell technology for enhanced signal-to-noise ratio</li><li>Wide selection of interchangeable analytical, semi-preparative, and preparative flow cells</li><li>Optional fiber-optic adapter for remote flow cell positioning</li><li>Internal holmium filter for wavelength verification</li><li>Integrated leak sensor</li><li>Front-access, tool-free lamp replacement</li><li>Compatible with ClarityChrom®, OpenLAB®, Chromeleon™, PurityChrom®, and Mobile Control</li><li>LAN and analog connectivity for easy integration into virtually any LC system</li></ul><h3>Technical Specifications</h3><h4>Detection System</h4><ul><li>Detector type: Diode Array Detector (DAD)</li><li>Number of diodes: 256</li><li>Pixel pitch: 2 nm per diode</li><li>Detection channels:<ul><li>8 digital channels</li><li>4 analog channels</li></ul></li><li>Light source: Deuterium lamp with integrated GLP chip</li><li>Wavelength range: 190–700 nm</li><li>Spectral resolution: &lt;10 nm (FWHM)</li><li>Slit width: 7.0 nm</li><li>Wavelength accuracy: ±1 nm</li><li>Wavelength repeatability: ±0.1 nm</li></ul><h4>Performance</h4><ul><li>Noise: ±5 µAU at 254 nm</li><li>Drift: 400 µAU/h at 254 nm</li><li>Linearity: &gt;2.0 AU at 274 nm</li><li>Maximum data rate:<ul><li>100 Hz via LAN</li><li>12.5 Hz via analog output</li></ul></li></ul><h4>Flow Cells</h4><ul><li>Flow cells are not included and must be ordered separately</li><li>Stainless steel and bio-inert configurations available</li><li>Optional LightGuide total-reflection technology</li></ul><h4>Control and Communication</h4><ul><li>LAN (RJ-45)</li><li>USB service interface</li><li>Analog inputs and outputs</li><li>Mobile Control stand-alone operation</li><li>Full software control through chromatography data systems</li></ul><h4>GLP Functions</h4><ul><li>Lamp identification</li><li>Lamp operating hours</li><li>Lamp ignition count</li><li>Comprehensive GLP reporting</li></ul><h4>Power and Dimensions</h4><ul><li>Power supply: 100–240 V, 50–60 Hz</li><li>Power consumption: 75 W</li><li>Dimensions (W × H × D): 361 × 158 × 523 mm</li><li>Weight: 12.2 kg</li></ul>

KNAUER AZURA DAD 6.1L Diode Array Detector

KNAUER AZURA® DAD 6.1L is a premium diode array detector with 190–1000 nm coverage, 1024-diode array, Polka-Dot optics, and LightGuide technology for maximum sensitivity.

The KNAUER AZURA® DAD 6.1L is a high-end diode array detector designed for analytical, semi-preparative, preparative, and process liquid chromatography applications. Featuring an extended wavelength range of 190–1000 nm, KNAUER Polka-Dot optical technology, and a 1024-diode array, it delivers exceptional sensitivity, spectral resolution, and baseline stability.The detector combines a high-brightness deuterium lamp and tungsten-halogen lamp to provide seamless UV and visible light detection. Optional LightGuide flow cells based on total internal reflection technology maximize light throughput while minimizing peak dispersion. An optional fiber-optic adapter enables physical separation of the flow cell from the detector, increasing safety when working with hazardous, explosive, or toxic compounds and protecting the detector from potential leaks at high flow rates.<h3>Key Features</h3><ul><li>High-end diode array detector for HPLC, UHPLC, and process chromatography</li><li>Extended wavelength range from 190 to 1000 nm</li><li>1024-diode array with 0.8 nm pixel pitch</li><li>KNAUER Polka-Dot optical technology for maximum sensitivity</li><li>LightGuide flow cell technology for superior signal-to-noise ratio</li><li>Wide range of analytical, semi-preparative, and preparative flow cells</li><li>Optional fiber-optic adapter for remote flow cell positioning</li><li>High-brightness deuterium and halogen lamps</li><li>Internal holmium filter for wavelength verification</li><li>Integrated leak sensor</li><li>Front-access lamp replacement</li><li>Compatible with ClarityChrom®, OpenLAB®, Chromeleon™, PurityChrom®, and Mobile Control</li><li>Suitable for both laboratory and process applications</li></ul><h3>Technical Specifications</h3><h4>Detection System</h4><ul><li>Detector type: Diode Array Detector (DAD)</li><li>Number of diodes: 1024</li><li>Pixel pitch: 0.8 nm per diode</li><li>Detection channels:<ul><li>8 digital channels</li><li>4 analog channels</li></ul></li><li>Light source:<ul><li>High-brightness deuterium lamp</li><li>Tungsten-halogen lamp</li></ul></li><li>Wavelength range: 190–1000 nm</li><li>Spectral resolution: &lt;3.5 nm (FWHM)</li><li>Slit width: 2.5 nm</li><li>Wavelength accuracy: ±1 nm</li><li>Wavelength repeatability: ±0.1 nm</li></ul><h4>Performance</h4><ul><li>Noise: ±3.5 µAU at 254 nm</li><li>Drift: 300 µAU/h at 254 nm</li><li>Linearity: &gt;2.5 AU at 274 nm</li><li>Maximum data rate:<ul><li>100 Hz via LAN</li><li>12.5 Hz via analog output</li></ul></li></ul><h4>Flow Cells</h4><ul><li>Flow cells sold separately</li><li>Stainless-steel and bio-inert configurations available</li><li>Optional LightGuide total-reflection technology</li></ul><h4>Control and Communication</h4><ul><li>LAN (RJ-45)</li><li>USB service interface</li><li>Analog inputs and outputs</li><li>Mobile Control stand-alone operation</li><li>Full software integration with chromatography data systems</li></ul><h4>GLP Functions</h4><ul><li>Lamp identification</li><li>Lamp operating hours</li><li>Lamp ignition count</li><li>Comprehensive GLP reporting</li></ul><h4>Power and Dimensions</h4><ul><li>Power supply: 100–240 V, 50–60 Hz</li><li>Power consumption: 75 W</li><li>Dimensions (W × H × D): 361 × 158 × 523 mm</li><li>Weight: 13.8 kg</li></ul>

KNAUER AZURA MWD 2.1L Multiwavelength Detector

KNAUER AZURA® MWD 2.1L is an 8-channel UV/VIS detector with 190–700 nm coverage, LightGuide technology, high sensitivity, and upgradeability to a DAD system.

The KNAUER AZURA® MWD 2.1L is a sensitive 8-channel UV/VIS multiwavelength detector designed for analytical, semi-preparative, and preparative liquid chromatography. Combining excellent performance, user-friendly operation, and affordability, it provides a versatile solution for routine and advanced LC applications.The detector features a newly developed optical unit and intelligent temperature management to ensure maximum sensitivity with minimal baseline drift. Optional LightGuide flow cells based on total internal reflection technology maximize light throughput and minimize peak dispersion, resulting in an optimized signal-to-noise ratio. An optional fiber-optic adapter allows physical separation of the flow cell from the detector, increasing safety when handling hazardous, explosive, or toxic materials.The AZURA® MWD 2.1L can also be upgraded to a full <a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/products/2423">AZURA® DAD 2.1L diode array detector</a>, protecting future investments and enabling greater analytical flexibility.<h3>Key Features</h3><ul><li>Sensitive 8-channel UV/VIS multiwavelength detector</li><li>Wavelength range from 190 to 700 nm</li><li>Simultaneous monitoring of up to 8 digital channels</li><li>LightGuide flow cell technology for improved sensitivity and signal-to-noise ratio</li><li>Intelligent temperature management for minimal baseline drift</li><li>Wide selection of analytical, semi-preparative, and preparative flow cells</li><li>Optional fiber-optic adapter for remote flow cell positioning</li><li>Internal holmium filter for wavelength verification</li><li>Integrated leak sensor</li><li>Front-access lamp replacement</li><li>Upgradeable to the AZURA® DAD 2.1L diode array detector</li><li>Compatible with ClarityChrom®, OpenLAB®, Chromeleon™, PurityChrom®, and Mobile Control</li></ul><h3>Technical Specifications</h3><h4>Detection System</h4><ul><li>Detector type: Multiwavelength Detector (MWD)</li><li>Digital channels: 8</li><li>Analog channels: 4</li><li>Light source: Deuterium lamp with integrated GLP chip</li><li>Wavelength range: 190–700 nm</li><li>Spectral resolution: &lt;10 nm (FWHM)</li><li>Slit width: 7.0 nm</li><li>Wavelength accuracy: ±1 nm</li><li>Wavelength repeatability: ±0.1 nm</li></ul><h4>Performance</h4><ul><li>Noise: ±5 µAU at 254 nm</li><li>Drift: 400 µAU/h at 254 nm</li><li>Linearity: &gt;2.0 AU at 274 nm</li><li>Maximum data rate:<ul><li>100 Hz via LAN</li><li>12.5 Hz via analog output</li></ul></li></ul><h4>Flow Cells</h4><ul><li>Flow cells sold separately</li><li>Stainless-steel and bio-inert configurations available</li><li>Optional LightGuide total-reflection technology</li></ul><h4>Control and Communication</h4><ul><li>LAN (RJ-45)</li><li>USB service interface</li><li>Analog inputs and outputs</li><li>Mobile Control stand-alone operation</li><li>Full software integration with chromatography data systems</li></ul><h4>GLP Functions</h4><ul><li>Lamp identification</li><li>Lamp operating hours</li><li>Lamp ignition count</li><li>Comprehensive GLP reporting</li></ul><h4>Power and Dimensions</h4><ul><li>Power supply: 100–240 V, 50–60 Hz</li><li>Power consumption: 75 W</li><li>Dimensions (W × H × D): 361 × 158 × 523 mm</li><li>Weight: 12.2 kg</li></ul>

Products from category PDA/DAD HPLC detectors focused on HPLC distributed by KNAUER - page 1

Related content

Invitation to the ALS Webinar PFAS in Water 2026: Achieving Compliance through Advanced Analytical Strategies

News from LabRulezLCMS Library - Week 24, 2026

Crimp vs. Screw Caps: Which is Better for Chromatography?