Sample preparation is one of the most time-consuming steps in analytical workflows. Whether a lab is conducting forensic analyses, environmental testing, pharmaceutical development, or food safety analysis, researchers often face the challenge of concentrating samples before analysis. <a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/article/5392">Nitrogen blowdown evaporation</a> has become a widely used technique for this purpose because it is simple, efficient, and adaptable to a wide range of solvents. When preparing samples for evaporation, factors that play a major role in efficiency include: needle gauge and flow rate. Optimization of these parameters could aid in developing more effective solvent evaporation methods.At Organomation, all <a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/products?category=362&amp;manufacturerItems=540&amp;page=2">blowdown evaporators</a> come with standard 4-inch, 19-gauge stainless steel needles. This size has proven to be effective for most laboratory applications as it balances evaporation speed with nitrogen consumption while also accommodating for common sample tube sizes. For labs that need to process higher sample volumes, 16-gauge and 14-gauge needles are also available. All needles are constructed from 304 stainless steel and feature a luer lock fitting for easy attachment and removal from the nitrogen evaporator.Traditionally, Organomation has recommended using a straight 19-gauge needle with a flow rate of 0.33 L/min per sample. This setting works well for most solvents, but how could changing these parameters aid in increasing evaporation efficiency?<ul><li>Could switching to a larger gauge needle accelerate evaporation?</li><li>Does increasing nitrogen flow rate always improve efficiency, or are there trade-offs?</li><li>Can needle design modifications reduce splashing while maintaining faster drying times?</li></ul>To investigate this, a series of controlled trials using methanol as a representative solvent were conducted. The study compared evaporation rates across different needle gauges, flow rates, and needle shapes to provide practical insights for laboratories seeking to optimize their sample preparation methods.<h3>Needle Variations</h3>While straight stainless-steel needles are the standard for nitrogen blowdown evaporation, alternative needle shapes may influence how nitrogen interacts with the solvent surface. Two main modifications were tested in this study:<ul><li>Bent needles: Designed with either a short bend or a long bend near the end of the needle. The goal was to change the angle of nitrogen delivery to reduce splashing and improve solvent exposure.</li><li>Pseudo-spiral needles: Created by adding two bends to the bottom quarter of 19-gauge needles, forming it into a spiral-like curve. These were intended to generate a more turbulent nitrogen flow pattern, potentially enhancing evaporation.</li></ul>Both designs were hypothesized to improve evaporation efficiency by concentrating gas flow while minimizing sample loss.<h3>Experimental Design</h3>The study evaluated how needle gauge, needle modifications, and nitrogen flow rate influence methanol evaporation under controlled conditions. All experiments were conducted at both room temperature and 63 °C, the recommended bath temperature for methanol.<h4>Needle Gauge</h4><ul><li>Compared 19-, 16- and 14-gauge needle evaporation rates.&nbsp;</li><li>Used each needle’s recommended flow rate<ul><li>19 ga: 0.33 L/min</li><li>16 ga: 0.83 L/min</li><li>14 ga: 1.2 L/min</li></ul></li><li>Purpose: determine whether larger needle diameters accelerate evaporation relative to the standard 19-gauge configuration.</li></ul><h4>Needle Modifications</h4><ul><li>Compared straight needles to bent and pseudo-spiral designs.&nbsp;</li><li>19- and 16-gauge needles were modified to have a short bend or long bend on the end of the needle.&nbsp;</li><li>Additional pseudo-spiral designs of the 19-gauge needles were created by bending the lower quarter of the needle into two spiral shapes.&nbsp;</li><li>Purpose: evaluate whether altering gas flow direction could improve evaporation rates.</li></ul><h4>Flow Rate Variation</h4><ul><li>Increased the nitrogen flow rate past original recommendations.</li><li>Used the recommended flow rate for 16-gauge needles on the 19-gauge bent needles.</li><li>Used the recommended flow rate for 14-gauge needles on the 16-gauge bent needles.</li><li>Purpose assess whether higher flow rates improve efficiency and if pairing higher flow rates with bent needles can reduce splashing.</li></ul><h3>Results</h3><h4>Table 1. Different Needle Sizes - Methanol Evaporation Rate</h4><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/Organomation_The_Effect_of_Needle_Gauge_and_Flow_Rate_on_Evaporation_Rate_2_17a8479b99.jpg" alt="Organomation: The Effect of Needle Gauge and Flow Rate on Evaporation Rate" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_Organomation_The_Effect_of_Needle_Gauge_and_Flow_Rate_on_Evaporation_Rate_2_17a8479b99.jpg 245w," sizes="100vw" width="1237" height="224">The 14-gauge had the fastest evaporation rate, which was expected, as the standard flow rate for this size needle is the fastest. All needle sizes showed an increase in evaporation when using the heated water bath.<h4>Table 2. 19-gauge Needle - Methanol Evaporation Rates</h4><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/Organomation_The_Effect_of_Needle_Gauge_and_Flow_Rate_on_Evaporation_Rate_3_01c176196e.jpg" alt="Organomation: The Effect of Needle Gauge and Flow Rate on Evaporation Rate" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_Organomation_The_Effect_of_Needle_Gauge_and_Flow_Rate_on_Evaporation_Rate_3_01c176196e.jpg 245w," sizes="100vw" width="1473" height="346"><h4>Table 3. 16-gauge Needle - Methanol Evaporation Rates</h4><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/Organomation_The_Effect_of_Needle_Gauge_and_Flow_Rate_on_Evaporation_Rate_4_ccd087323f.jpg" alt="Organomation: The Effect of Needle Gauge and Flow Rate on Evaporation Rate" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_Organomation_The_Effect_of_Needle_Gauge_and_Flow_Rate_on_Evaporation_Rate_4_ccd087323f.jpg 245w," sizes="100vw" width="1473" height="222">The most effective needle shape for both the 19- and 16-gauge needles, without increasing nitrogen flow rate, proved to be the standard straight needles for both room temperature and heated water bath evaporation. There was a significant jump observed in the heated evaporation, especially in the 16-gauge needles, with over 75% increase. When comparing the short and long bend needle configurations, there were no significant differences, as the style with faster evaporation varied between trials.<h4>Table. 4 Methanol Evaporation Rates with Increased Flow Rates</h4><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/Organomation_The_Effect_of_Needle_Gauge_and_Flow_Rate_on_Evaporation_Rate_5_4c4ba4d1d8.jpg" alt="Organomation: The Effect of Needle Gauge and Flow Rate on Evaporation Rate" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_Organomation_The_Effect_of_Needle_Gauge_and_Flow_Rate_on_Evaporation_Rate_5_4c4ba4d1d8.jpg 245w," sizes="100vw" width="1524" height="388">At room temperature, bent needles showed only a slight improvement in evaporation rates compared to larger gauge straight needles at the same flow rates. However, under heated water bath conditions, needle gauge size played a more significant role. The larger-gauge straight needles achieved substantially higher evaporation rates than bent needles at comparable flow rates. This indicates that gauge size and flow rate have a stronger influence than needle shape when a heated water bath is used.<h3>Key Takeaways</h3><ul><li>19-gauge needles remain reliable, especially at higher-than-standard flow rates.</li><li>Flow rate is critical: higher flow rates generally increased evaporation speed, but also introduced challenges such as potential sample splashing</li><li>Heated baths amplify overall performance: all needles performed significantly better at 63 °C water baths than at room temperature.</li><li>Needle design benefits: bent needles showed potential in minimizing splashing. They allowed for increased flow rate and for the needle to be closer to the sample solution inside the tube.</li></ul><h3>Applying These Findings in Your Lab</h3>The results of this study show that needle gauge, flow rate, and needle design can all significantly influence evaporation speed. But how do these findings translate into day-to-day laboratory use?<ul><li>Stick with the standard setup for most workflows. For routine sample preparation, the 19-gauge needle at 0.33 L/min remains an ideal choice, offering reliable performance while minimizing nitrogen consumption.</li><li>If your lab works with high-volume samples or needs quicker turnaround, switching to a 16-gauge needle and increasing the flow rate from 0.83 L/min to 1.2 L/min could provide significant time savings especially when paired with a heated water bath.</li><li>Faster nitrogen delivery can improve speed, but it also increases the risk of sample loss. Start by slowly increasing flow rate, and then adjust needle position above the solvent surface to control splashing.</li><li>Consider using bent or spiral needles for reducing splashing while maintaining strong evaporation rates. While not always necessary, they may be helpful in some scenarios.</li></ul><h3>Conclusion</h3>For most applications, the standard 19-gauge, 0.33 L/min setting remains sufficient. However, labs working with high-volume samples or those needing faster evaporation can benefit from using 16-gauge needles at higher flow rates, especially when paired with a heated water bath. Needle modifications can help address the issue of sample splashing, although they have shown to decrease the rate of evaporation when compared to the standard straight needles of the same gauge. Ultimately, the choice of needle gauge and flow rate should balance speed, safety, and solvent conservation. These results provide a framework for labs looking to optimize their evaporation setup.<blockquote><a target="_blank" rel="noopener noreferrer" href="https://www.organomation.com/contact">Contact our team</a> to discuss the best needle option and gas parameters for your application.</blockquote>

The Effect of Needle Gauge and Flow Rate on Evaporation Rate

How can we make the production of supercapacitors for energy storage more sustainable and replace the traditionally used but toxic solvent NMP (N-methyl-2-pyrrolidone)? According to scientists from CATRIN at Palacký University, the “green” solvents Cyrene and Tamisolve may be a suitable alternative. In an article published in the <a target="_blank" rel="noopener noreferrer" href="https://www.sciencedirect.com/science/article/pii/S1385894725130696?via%3Dihub#s0060">Chemical Engineering Journal</a>, they have shown that these solvents can be used in production without reducing the performance of the equipment. They thus offer a path to the next generation of sustainable, high-performance supercapacitors for industrial use.“Supercapacitors are one of the modern technologies for storing electric energy. As sustainable energy storage becomes more prominent, it is essential to replace the hazardous solvents used in the production of supercapacitor electrodes. Our study presents Cyrene and Tamisolve as environmentally friendly alternatives to the toxic solvent NMP, which is traditionally used in production. Both tested solvents enabled the preparation of electrodes that maintain high electrochemical performance while improving environmental compatibility,” said Michal Otyepka, corresponding author of the article.The electrodes were prepared using nitrogen-doped graphene as the active material in combination with two types of binders. The first was a common fluorinated binder (PVDF), which is widely used in industry, including in the manufacturing of battery electrodes. The researchers also tested a fluorine-free binder (PVP), which has a lower environmental impact and is more soluble in environmentally friendly solvents. Using various combinations, they monitored the performance and stability of the electrodes as well as their mechanical resistance.<img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/CATRIN_Vedci_z_CATRIN_nabizeji_zelenejsi_cestu_pro_vyrobu_superkondenzatoru_443775296a.jpg" alt="CATRIN: CATRIN researchers offer a “greener” way to make supercapacitors" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_CATRIN_Vedci_z_CATRIN_nabizeji_zelenejsi_cestu_pro_vyrobu_superkondenzatoru_443775296a.jpg 245w," sizes="100vw" width="1536" height="768">“The results showed that not only can the alternative solvents Cyrene and Tamisolve fully replace the toxic solvent NMP, but also that the prepared electrodes have the necessary mechanical properties. Their compatibility with both fluorinated PVDF and non-fluorinated PVP binders, together with excellent layer uniformity and electrochemical stability, makes them ideal for use in scalable applications. This is essential for industrial production,” said the publication’s first author, Ivan Dědek.Cyrene, or dihydrolevoglucosenone, is obtained from renewable biomass sources such as cellulose. Tamisolve (N-butyl-2-pyrrolidone) is a substance related to the commonly used NMP, but is more gentle on human health and the environment.Supercapacitor research has been a priority at CATRIN for almost ten years. In addition to developing new active materials, such as the successful nitrogen-doped graphene (SC-GN3), it also focuses on environmentally friendly and industrially feasible manufacturing processes. The replacement of toxic NMP with the “greener” solvents Cyrene and Tamisolve confirms that more sustainable production can go hand in hand with high performance and represents an important step towards industrial implementation.<blockquote><h4>The original article</h4><h4><a target="_blank" rel="noopener noreferrer" href="https://www.sciencedirect.com/science/article/pii/S1385894725130696?via%3Dihub#s0060">Toward transitioning to green and sustainable supercapacitors</a></h4>Ivan Dědek, Vojtěch Kupka, Veronika Šedajová, Petr Jakubec, Matěj Navrátil, Michal Otyepka&nbsp;Chemical Engineering Journal, 529, 2026, 172220<a target="_blank" rel="noopener noreferrer" href="https://doi.org/10.1016/j.cej.2025.172220">https://doi.org/10.1016/j.cej.2025.172220</a><h6>licensed under <a target="_blank" rel="noopener noreferrer" href="https://creativecommons.org/licenses/by/4.0/">CC-BY 4.0</a></h6></blockquote><h4>Abstract</h4>The rapid advancement of supercapacitor technologies has intensified the demand for sustainable electrode fabrication methods that minimize environmental impact. A major challenge arises from the extensive use of the toxic solvent N-methyl-2-pyrrolidone (NMP), which is subject to increasingly stringent regulatory restrictions. We demonstrate that NMP can be effectively replaced with two green solvents, dihydrolevoglucosenone (Cyrene) and N-butyl-2-pyrrolidone (Tamisolve), without compromising electrochemical performance. Electrode formulations were prepared using nitrogen-doped graphene as the active material, in combination with either polyvinylidene fluoride (PVDF), a widely employed fluorinated binder, or polyvinylpyrrolidone (PVP), a non-fluorinated alternative with improved environmental profile. Optimized coatings exhibited high mass loadings exceeding 6 mg cm−2 while maintaining strong adhesion to current collectors, an often overlooked yet critical parameter for scalable manufacturing. Electrochemical testing revealed that PVDF in Cyrene delivered an energy density of 66.6 Wh kg−1 at a power density of 1.85 kW kg−1, with excellent cycling stability, retaining 91 % of capacitance after 100,000 cycles. PVP in Cyrene provided a more environmentally benign alternative, achieving an energy density of 64.2 Wh kg−1 at 1.80 kW kg−1, with 78 % capacitance retention after 100,000 cycles, thereby highlighting the trade-off between performance and sustainability.

CATRIN researchers offer a “greener” way to make supercapacitors

🎤Dr. Kristen Vanderveen (Dr. Vanderveen's chemistry education content on YouTube: @<a target="_blank" rel="noopener noreferrer" href="https://www.youtube.com/@drvchemistry">drvchemistry</a>)Dr. Kristen Vanderveen is a chemistry teacher at The Bromfield School with over 20 years of experience teaching high school chemistry, including AP Chemistry. Her background includes working as a protein chemist before transitioning to education.In this episode of Concentrating on Chromatography, David interviews his former high school chemistry teacher, Dr. Kristen Vanderveen from The Bromfield School, about teaching separation science at the high school level.Dr. Vanderveen shares her approach to introducing chromatography, filtration, and gravimetric analysis to both first-year chemistry students and AP Chemistry students. She discusses the hands-on experiments that work best in a high school setting, including paper chromatography with food dyes, TLC separations, and the challenges of balancing lab time with curriculum requirements.<h4>Topics discussed:</h4><ul><li>Separation methods taught in high school chemistry (filtration, paper chromatography, TLC)</li><li>Gravimetric analysis and precipitation experiments for AP Chemistry</li><li>Student engagement strategies and memorable lab activities</li><li>Balancing theoretical concepts with hands-on experimentation</li><li>Common student misconceptions about separation techniques</li><li>Preparing students for college-level chemistry courses</li></ul><h3>Video Transcription</h3><h4>How Separation Science Is Introduced in High School Chemistry</h4>Separation science may seem like an advanced topic associated mainly with research laboratories and analytical instrumentation, but its foundations are introduced much earlier. In this interview, chemistry teacher Kristen reflects on how separation methods are taught at the high school level, especially in AP Chemistry, and how these early experiences help prepare students for future studies in chemistry and related fields.<h4>Filtration and chromatography as core teaching tools</h4>According to Kristen, one of the most important separation techniques taught in high school chemistry is filtration, particularly through gravimetric analysis. In AP Chemistry, students are expected to understand how to form, isolate, dry, and weigh a precipitate, making filtration one of the most frequently practiced laboratory skills. These exercises help students connect separation techniques with stoichiometry, quantitative analysis, and proper laboratory handling.Another key topic is chromatography. Although AP Chemistry does not cover chromatography in great technical depth, students are introduced to important principles such as the stationary phase, mobile phase, solvent front, and Rf values. Kristen explains that these ideas are most effectively learned through hands-on experiments, which is why she regularly includes paper chromatography and, in some cases, thin-layer chromatography (TLC) in her classes.<h4>Hands-on experiments make the concepts real</h4>Among the most engaging classroom activities are chromatography labs based on food dyes and marker inks. Students may begin with a guided exercise to learn how to spot samples, prepare chromatography chambers, and compare separations under different solvent conditions. In more advanced versions of the experiment, they are asked to design their own solvent systems to optimize the separation of selected dyes and then present their findings in a small poster format.Kristen notes that these activities help students understand not only the scientific principle but also the practical challenges of separations. They quickly learn that details matter — for example, how sample spotting affects band shape, or how easy it is to make errors by placing the paper incorrectly in the solvent. These moments often become valuable “aha” experiences, showing students that experimental science requires patience, repetition, and careful observation.<h4>Balancing theory, time, and skill development</h4>One of the biggest challenges in teaching separation science at the high school level is limited classroom time. Modern school schedules, AP curriculum demands, and the need to teach many other foundational laboratory skills mean that only a few separation methods can be explored in depth. While students are introduced to concepts such as distillation, evaporation, and decanting, chromatography and filtration are the main techniques they actively practice.Kristen emphasizes that the goal is not to make students experts, but to ensure they leave high school with enough familiarity to succeed in college-level chemistry. If they have filtered a precipitate, seen chromatography in action, and understand that mixtures can be separated based on physical and chemical properties, then they are better prepared for more advanced topics such as separatory funnels, column chromatography, GC-MS, or LC-MS later in their education.<h4>Building the bridge to future chemistry careers</h4>The interview also highlights a broader point: high school chemistry is often the first point of contact students have with analytical thinking and laboratory separation methods. While they may not yet know about the full range of chromatographic and mass spectrometric techniques used in research and industry, these early lab experiences build the conceptual framework needed for future growth.Kristen also points out that students are often unaware of the many careers connected to analytical chemistry beyond academia. From teaching and research to applications science, instrument support, and industrial laboratories, separation science opens doors to a wide range of scientific paths. High school exposure may be basic, but it plays an important role in making those future possibilities accessible.<blockquote>This text has been automatically transcribed from a video presentation using AI technology. It may contain inaccuracies and is not guaranteed to be 100% correct.</blockquote><blockquote><h4>Concentrating on Chromatography Podcast</h4>Dive into the frontiers of chromatography, mass spectrometry, and sample preparation with host David Oliva. Each episode features candid conversations with leading researchers, industry innovators, and passionate scientists who are shaping the future of analytical chemistry. From decoding PFAS detection challenges to exploring the latest in AI-assisted liquid chromatography, this show uncovers practical workflows, sustainability breakthroughs, and the real-world impact of separation science. Whether you’re a chromatographer, lab professional, or researcher you'll discover inspiring content!You can find Concentrating on Chromatography Podcast in podcast apps:<ul><li><a target="_blank" rel="noopener noreferrer" href="https://open.spotify.com/show/1wZg67rCjoGju4yhqxI3tL">Spotify</a></li><li><a target="_blank" rel="noopener noreferrer" href="https://podcasts.apple.com/tz/podcast/concentrating-on-chromatography/id1788429185">Apple podcast</a></li><li><a target="_blank" rel="noopener noreferrer" href="https://podscan.fm/podcasts/concentrating-on-chromatography">podscan</a></li></ul>and on <a target="_blank" rel="noopener noreferrer" href="https://www.youtube.com/@ChromatographyTalk/videos">YouTube channel</a></blockquote>

Teaching Separation Science in High School

Article

Product

Academy

Video

Scientists

Scientific article

Interview

Science and research

The Czech Advanced Technology and Research Institute (CATRIN) at Palacký University is a cutting-edge scientific hub dedicated to advancing research in the fields of nanotechnology, biotechnology, and biomedicine. At its core, CATRIN boasts outstanding scientific teams, featuring international researchers. We emphasize interdisciplinarity, foster global collaborations, and work to translate our research findings into practical applications.

CATRIN

Organomation, founded in 1959, designs and manufactures high-quality nitrogen evaporators and extraction systems. Known for innovation and durability, their lab instruments are used globally for efficient sample preparation with strong customer support.

Organomation

SIELC Alltesta Mini HPLC Autosampler (Special offer - New)

The Alltesta™ Mini Autosampler offers a cost-effective and reliable solution for automated sample processing across a range of analytical and liquid handling applications, including HPLC.

SIELC Samplify Automated sampling system (Special offer - New)

Samplify™ Is a device which allows unattended sampling of a reaction mixture or bioprocess or continue in line flow by taking small amount of liquid from the monitoring mixture and collecting it in a vial or a 96 wells plate.

SIELC Alltesta Gradient Automated HPLC Analyzer (Special offer - New)

SIELC’s Alltesta™ Analyzer is an affordable HPLC analytical system with for measuring small and trace concentrations of various chemicals.

SIELC Alltesta Cromite HPLC Analyzer (Special offer - New)

The Cromite™ analyzer represents a new generation of affordable, easy-to-use HPLC instruments for schools and universities.

Bazaar products from SIELC - page 1

Related content

Teaching Separation Science in High School

CATRIN researchers offer a “greener” way to make supercapacitors

The Effect of Needle Gauge and Flow Rate on Evaporation Rate