The Advantages of 96-Well Plates and Sealing Cap Mats in Chromatography
96-well plates are becoming increasingly popular in chromatography and analytical workflows because of their high-throughput capability, compatibility with automation, and efficiency in sample preparation and storage. They enable the simultaneous processing of up to 96 samples, dramatically increasing throughput, reducing costs, and minimizing human error through automated handling. Their standardized well plate format also ensures compatibility with a wide range of robotic systems and analytical instruments, including liquid handlers and autosamplers commonly used in LC-MS applications. Main Advantages: High-throughput: A single plate can process 96 or even 384 samples at once, offering a major efficiency boost for high-throughput screening and analytical workflows. Automation compatibility: The standardized plate format integrates seamlessly with robotic systems for liquid handling, sample preparation, and loading—reducing manual error and increasing speed. Efficiency: Running many samples in parallel streamlines workflows, cuts down processing time, and lowers costs compared to handling individual vials. Sample preparation: 96-well formats are ideal for automated sample cleanup techniques such as solid-phase extraction (SPE) prior to LC-MS analysis. Sample storage: Plates provide a compact, organized, and standardized way to store large numbers of samples before or after analysis. The Key Importance of Proper Sealing To protect samples from contamination, evaporation, and cross-contamination between wells, an appropriate closure system is essential. Common sealing options include adhesive films (clear or aluminum) and silicone sealing mats (Cap Mats). Silicone sealing Cap Mats form a mechanical seal by capping each well simultaneously. They protect contents during assays, incubation, shaking, or long-term storage. These mats are available in various formats (flat or domed wells) and they remain stable across a wide temperature range: from autoclaving to cold storage temperatures. For workflows requiring access without removing the seal, pre-slit or pierceable silicone Cap Mats allow pipette tips or needles to penetrate while maintaining a tight reseal afterward. Choosing the Right Sealing Solution When selecting the best sealing method for your workflow, consider the following: Repeated or Long-Term Use: Adhesive films typically do not reseal after puncture, making them single-use. Silicone Cap Mats, however, reseal automatically, allowing multiple injections or sample withdrawals while preventing evaporation or concentration changes. Shaking, Mixing, or Centrifugation: Silicone Cap Matsmaintain a tight mechanical seal that won’t peel or loosen under agitation. Adhesive films can bubble, wrinkle, or detach during shaking or vortexing. High-Temperature or Sterilization Conditions: Platinum-cured silicone mats tolerate autoclaving (121 °C) and incubator conditions without degradation. Many adhesive films, however, can melt, warp, or leave residues when exposed to heat, making them unsuitable for sterilization or repeated heating cycles. Large-Scale Screening or Automation: Silicone mats are dimensionally consistent and compatible with robotic systems, allowing repeated piercing and resealing by automated liquid handlers. Adhesive films, on the other hand, are prone to tearing or sticking to robotic tips. Optical Measurements (PCR, Fluorescence): For optical assays that require light transmission, clear adhesive films are preferred since silicone Cap Mats can interfere with optical readings. Why Does Silicone Quality and Curing Method Matter on Well Plates Sealing Cap Mats? Not all silicone is created equal. The curing method used to convert silicone from a liquid polymer into a solid elastomer significantly affects purity, mechanical strength, and chemical resistance. What Does “Curing” Mean? “Curing” refers to the chemical crosslinking of silicone polymer chains using a catalyst, transforming the liquid polymer into a flexible, durable solid. The two main curing systems are platinum-cured (addition-cured) and peroxide-cured (free radical) silicone. Platinum-Cured Silicone Platinum-cured silicone uses a platinum catalyst to link hydride (-SiH) and vinyl (-CH=CH₂) groups on the polymer chains. Advantages include: Extremely pure and inert — no residual catalysts or byproducts. Odorless and non-leaching — ideal for biological or chemical assays. Excellent mechanical and thermal stability — withstands repeated autoclaving. Superior clarity and long-term color stability. Biocompatible and FDA/USP compliant — suitable for medical and food applications. Very low extractables and volatiles — critical for sensitive LC/MS or enzymatic work. Peroxide-Cured Silicone Peroxide curing uses organic peroxides that generate free radicals to crosslink silicone chains. This method produces volatile byproducts (e.g., acetic acid, alcohols, and water) that must be removed by post-curing. Disadvantages include: Potential contamination from residual byproducts. Odor and discoloration over time. Lower purity and thermal stability. While peroxide-cured silicone is cost-effective and acceptable for industrial uses (e.g., seals, gaskets, tubing), it’s less suitable for analytical or biological applications. Why is Platinum-Cured Silicone Preferred in Labs? For 96- and 384-well plate sealing Cap Mats, platinum-cured silicone is the clear choice because it: Avoids contamination of biological or chemical assays (critical for PCR, enzymatic, and pharmaceutical work). Withstands autoclaving, solvent exposure, and temperature cycling without degradation. Maintains consistent elasticity and compression for a reliable seal over multiple uses. In contrast, peroxide-cured silicone may release trace impurities that can: Interfere with enzyme reactions or cell cultures. Skew fluorescence or absorbance measurements. Contaminate analytical instruments such as LC/MS or GC systems. Platinum-cured silicones also offer better tensile strength, elongation, and durability across a wide temperature range. They resist degradation, exhibit minimal extractables, and release virtually no volatile organic compounds (VOCs), ensuring clean, reliable analytical results. SSP’s Ultra Low Bleed platinum-cured silicone mats are formulated to minimize siloxane peaks, helping ensure interference-free chromatography and LC/MS data. Their consistency and purity make them the gold standard for laboratory and medical sealing applications. Cap Mat Customization to Meet Unique Needs At SSP, we understand that some projects require bespoke solutions. That’s why we offer custom cap mat configurations, including unique designs and colors. Our in-house, on-site machine shop allows us to design, build, and maintain custom molds efficiently, reducing lead times and costs. Whether you need a specific color to differentiate between samples or a unique design for a specialized application, SSP can accommodate your requirements. All our cap mats are manufactured at our facility in Ballston Spa, New York, ensuring stringent quality control and adherence to high manufacturing standards. We take pride in producing reliable, high-quality products that support critical analytical research and laboratory testing. Custom 96-well Cap Mats Tailored to Your Needs At SSP, we recognize that some projects demand more than standard solutions. That’s why we
