© 2026 Nanjing Finechem Holdings Co., Ltd,
All Right Reserved
Years ago, the possibilities around modifying biomolecules grabbed attention in chemistry labs. Researchers wanted ways to link proteins and peptides to sensors, surfaces, or other biomolecules. In the ‘60s and ‘70s, maleimide groups earned their spotlight for their ability to form stable thioether bonds with thiol groups – you find plenty of thiols on cysteine residues in proteins. The simple maleimide core changed the game, but its derivatives like N-(2-Aminoethyl)maleimide took this approach further. Adding an aminoethyl arm let chemists easily connect this crosslinker with all sorts of targets using standard coupling reactions. The trifluoroacetate salt form doesn’t grab headlines for its excitement, but it addresses the core challenge: solubility and handling for sensitive protocols. People in research and biotech wouldn’t bother with it if the core functional group didn’t actually fulfill its molecular promise.
N-(2-Aminoethyl)maleimide trifluoroacetate salt stands out because it brings together two groups chemists love to use: an amine on one end and a maleimide on the other. That combination offers precise targeting in both protein and small molecule chemistry. The maleimide reacts fast and specifically with sulfhydryl groups, forming a stable link that survives the rough-and-tumble of most downstream applications. The amine end, beyond acting as a handy grab point, also lets the compound hook up with other linker chemistries – such as NHS-esters – multiplying its use in creating custom bioconjugates like antibody-drug conjugates or labeled peptides.
No one lines up to praise the physical quirks of their reagents, but anyone who’s ever fumbled with a poorly soluble or overly sticky chemical knows the pain. This salt form dissolves well in water and standard buffers, thanks in part to the trifluoroacetate ion that brings it into practical territory. No need to force things into strange solvents or risk denaturing sensitive biomolecules. In the weighing boat, it shows itself as a powder – a practical touch for the busy lab. Chemically, its maleimide group keeps up a fine balance: reactive enough to grab onto thiols, but stable enough to sit tight until it meets its partner.
Anyone aiming for reproducibility – which includes every decent scientist – cares a lot about how something is made and described. The synthetic path usually kicks off with maleic anhydride, which gets converted to maleimide and coupled to the aminoethyl side-chain via standard amination steps. After synthesis, converting the free base to the trifluoroacetate ensures the final product comes out in a stable, easy-to-handle form. When labeling a vial, people don’t just scribble a code: they include information about purity, molecular weight, exact salt form, and recommended storage conditions. These are not just regulatory chores; knowing exactly what’s in the bottle saves time troubleshooting and ensures consistent results.
Chemists put their faith in predictable reactions. The maleimide part of this compound isn’t shy about reacting with cysteine residues on peptides and proteins through Michael addition – a well-mapped out maneuver in molecular biology. Once attached, the bond between maleimide and thiol is sturdy and keeps the new conjugate intact under most experimental conditions. On the other end, the amino group opens up access to a world of other reactions like coupling with carboxylic acids in peptide synthesis. Some creative types use the amine as a platform to attach fluorescent dyes or affinity tags, letting them track or isolate their molecules of interest. This dual-reactivity punches well above its weight in allowing people to build tailor-made molecular assemblies.
Chemicals often wear their history in a parade of synonyms, and this one marches under several banners: 2-Aminoethylmaleimide trifluoroacetate, AEM-TFA, and sometimes AE-Mal trifluoroacetate. While this may seem like jargon to outsiders, those working with these tools find the right name in catalogs and publications makes a difference. Consistent naming ensures researchers buy what they actually need, sparing themselves nasty surprises at the bench.
Safety shapes every hand movement in a lab, not out of paranoia but from deep habit born of experience. This compound brings some risks, as anything with a reactive maleimide does. While usually not a headline toxin, it can cause irritation or worse if splashed in eyes or inhaled as powder. Containers must stay tightly closed and handled in a fume hood, with gloves and lab coats as non-negotiable accessories. Disposal matters too – no one wants a slow drip of reactive organics finding their way into waste streams. Institutions and regulators have answers: standard protocols and guidelines that protect not only those working at the bench but those who manage the broader environment.
Interest in modifying proteins, tracking cell pathways, or building complex bioconjugates keeps this compound relevant. It shows up in drug development, particularly in ADCs, where the ability to attach a cytotoxic payload to an antibody using a reliable and stable linker is vital. In diagnostic research, attaching fluorescent molecules or biotin to antibodies and peptides using this bifunctional linker takes some of the guesswork out of developing assays and imaging protocols. The predictable way it reacts and the ability to cleanly connect two very different chemistries – a thiol and an amine – helps it carve out a dependable niche in cutting-edge labs.
Research keeps running on creative use of old tools. N-(2-Aminoethyl)maleimide trifluoroacetate isn’t new in the broad sense, but its application continues to expand. People looking for new ways to immobilize enzymes, design biosensors, or tag cell-surface proteins often drift back to this molecule’s straightforward, well-documented reactivity. I’ve watched labs roll out new protocols based on slight tweaks to crosslinking steps, getting results nobody expected a generation ago. It finds room in next-gen therapies, biosensor builds, or even as a stopgap in urgent custom projects where off-the-shelf doesn’t cut it.
Anyone developing therapeutics or diagnostics pays close attention to toxicity data. Maleimide-driven links tend to be pretty stable in the bloodstream, but unreacted maleimide or the byproducts need careful evaluation. Cell-based studies and animal models give plenty of insight; the goal is always to ensure that chemical tools used in biological systems don’t make themselves the main story through unwanted toxicity. That concern winds its way through every safety review and product certification, especially for anything aimed at clinical trials or human diagnostics.
Despite decades of use, N-(2-Aminoethyl)maleimide trifluoroacetate salt doesn’t look like it’s leaving the chemical toolbox any time soon. Trends in precision medicine and biomarker discovery drive ongoing demand for customizable linker chemistry. New derivatives may bring marginal improvements, perhaps by tuning solubility, reactivity, or biocompatibility, but the basic principle holds strong: keep reactions selective, predictable, and easy to handle. Improvements in synthetic routes, greener production methods, and streamlined labeling stand to make it even more accessible. Listening to bench scientists who use this compound daily drives genuine progress – not just glossy marketing or incremental tweaks.
I’ve seen a lot of tools come and go in the lab, but some chemicals stick around because they solve problems the old-fashioned way—by just working. N-(2-Aminoethyl)maleimide trifluoroacetate salt helps researchers build connections at the tiniest level. Its role in biochemistry and drug development is all about getting precise links between molecules. Many labs use it to connect proteins or peptides because its structure offers two functional groups: the maleimide, which seeks out thiol (–SH) groups, and the amine, which lends itself to all kinds of modifications.
Anyone who’s spent time in protein science knows that getting two molecules to shake hands is rarely straightforward. This salt gives scientists control, especially in creating antibody-drug conjugates, fluorescent labeling, and even immobilizing enzymes on surfaces. Imagine scientists wanting to track a protein’s location in a cell. If the protein has a cysteine (which carries the right –SH group), this compound grabs on tight, helping attach dyes or other probes. That tracking isn’t just for curiosity, either. Cancer diagnostics, vaccine development, and research into Alzheimer’s all benefit from these connections.
Bioconjugation might seem like a technical trick, but lives ride on how well it works. Enzyme-linked immunosorbent assays (ELISAs) improve with stable attachments between proteins and detection molecules. Diagnostics move faster and give clearer answers. Drug delivery research gets another tool for putting treatment where it’s needed, instead of just everywhere in the body. Companies have used maleimide linkers in antibody-drug conjugates that offer targeted cancer therapies, reducing side effects and improving patient outcomes.
Nothing comes without questions. Some researchers wonder about safety, waste, and stability. I’ve learned to respect any compound that reacts quickly with proteins, since that same reactivity can cause trouble if you’re careless. Good ventilation, gloves, and attention to disposal rules keep problems at bay. After using these maleimide reagents in collaborative work, one thing stands out: planning makes or breaks the experiment. Letting the salt come in contact with water too early, or storing it under poor conditions, leads to lost time and ruined batches.
Not every application turns out perfect. Sometimes other parts of the protein, like lysines, get involved unintentionally, creating cross-links where they aren’t wanted. Buffer choice, pH, and concentration all matter. Small procedural tweaks often solve these headaches—keep solutions at neutral pH, prepare fresh stock, and don’t rush the reaction. Vendors have made purity better over time, trimming down side-products that muddle results. Information-sharing, whether through research papers or lab supply forums, also helps the community dodge common pitfalls.
Demand for smart, controlled bioconjugation just keeps rising. As therapies get trickier—think gene editing or precision medicine—compounds like N-(2-Aminoethyl)maleimide trifluoroacetate salt won’t fade away. Instead, the call grows for clear labeling, improved safety data, and reliable sourcing. Companies that support clear documentation, supply chain transparency, and honest purity checks help science move forward. This salt serves as one more small but mighty cog in the complex machinery of progress.
Every chemist learns pretty early that a compound’s molecular weight shapes everything we expect from it in the lab. N-(2-Aminoethyl)maleimide trifluoroacetate salt usually appears on reagent lists, especially for projects that link proteins or modify peptides. There’s a good reason for that: its reactive nature makes it a nearly irreplaceable tool for bioconjugation.
Getting the molecular weight right matters more than hitting the theoretical value. For researchers, that number influences how much of the substance actually ends up in a reaction mixture. Using too much or too little shifts outcomes, skews data, and wastes precious samples. Nobody likes to see weeks of work come undone because of a miscalculation.
Let’s nail down the key numbers. The neutral form, N-(2-Aminoethyl)maleimide, carries a formula weight of about 128.14 g/mol. But the trifluoroacetate salt version adds bulk due to the salt's counterion. Once you combine the maleimide core with the trifluoroacetate piece—CF3COO-—the weight jumps to roughly 261.17 g/mol. For anyone following credible supplier data, this aligns with most product sheets and matches the formula C6H10N2O2 · C2HF3O2.
Lab accuracy starts with the basics. When I prepped protein labeling experiments in grad school, using the wrong form of a reagent tanked my yield. The difference? I’d overlooked the salt's presence, causing my calculations to go off the rails. That extra trifluoroacetate group meant I didn’t have as much active compound as I thought. Several attempts later, I adjusted for the actual molecular weight—and my reactions ran clean and efficient.
In pharmaceutical research and diagnostics, reproducibility keeps doors open. Labs run dozens of labeling experiments that depend on this salt. Mix-ups due to molecular weight often lead to inconsistent protein coupling or even failed bioassays. Teams invest time chasing “unknown errors,” when a closer look at the salt content usually reveals the real culprit.
Confusion creeps in because many suppliers list both the free base and the salt versions with similar chemical names. Without double-checking the label, a rushed scientist might enter the smaller, free-base value into their calculations. That error multiplies every time solutions are made in bulk, messing up everything downstream in terms of yields and purity.
Quality assurance teams can’t slack on these details. Even minor miscalculations affect stability, solubility, and reaction kinetics. Hospitals and biotech companies prefer salts like trifluoroacetate because they boost shelf stability and support easier solubilization for sensitive assays.
I’ve seen teams establish a hard rule: verify the formula weight against supplier specs each time a new batch gets opened. This habit looks minor, but it saves entire research budgets and keeps records clean for regulatory reviews.
No synthetic chemist or biologist wants to waste time rerunning experiments. It often comes down to respecting known facts: N-(2-Aminoethyl)maleimide trifluoroacetate salt brings a molecular weight of around 261.17 g/mol to the bench. Ignoring that not only delays projects, but also pulls resources away from true discovery. Careful calculation builds trust in the data—inside companies, across collaborating labs, and in published work.
A lab benches plenty of hazards, but few get as little thought as the shelves storing all those little bottles. That’s too risky with something like N-(2-Aminoethyl)maleimide Trifluoroacetate Salt. This compound delivers powerful results in protein conjugation and labeling work, and anybody working with crosslinking knows its maleimide group demands respect. A little heat, a little light, even a bit too much oxygen—things can go off the rails. No researcher wants to discover the hard way that their precious stock has gone to waste or worse, contaminated the workspace.
With this salt, exposure to moisture doesn’t just risk clumping. Water can wreck the maleimide group, causing hydrolysis and impacting how it performs in sensitive reactions. I’ve seen researchers scramble after losing stability or reactivity, desperate to reorder and revalidate assays. Keeping the bottle tightly sealed saves a lot of headaches. If the salt pulls water from humid air—even overnight—you’ll definitely notice strange results later.
Low temperatures offer another layer of protection. Most vendors include a storage recommendation around 2–8°C, which points right at the lab fridge. A cheap digital thermometer pays off here. You leave a bottle on the bench for a few hours, and it won’t look different, but put it to use and you’ll learn all about instability. Short-term temperature spikes or daily cycling stress the compound, so a consistent fridge spot (never a freezer, unless explicitly labeled by the supplier) delivers peace of mind and product lifespan.
Maleimide groups react with more than just proteins. Direct sunlight or even common room lights push unwanted photochemical changes, leaving you staring at altered compounds with reduced activity. I spent an afternoon building cardboard shields for certain reagents after a month of strange yields. Turns out a dark, dry box in the fridge does far more than a dim shelf.
Desiccants make an enormous difference. A silica pack left in the bottle, changed every so often, removes worry over ambient moisture. Every time you open the cap to weigh out a few milligrams, seal it right back. If you only open the bottle for a minute, you skip temperature swings and humidity exchange that ruin shelf life. Label the container with the date received and opened. Measure out only what is needed, and leave the rest untouched—old habits that saved me from plenty of headaches and bad data.
With specialty salts, disposal never means down the drain or a regular garbage bin. Follow institutional protocols for hazardous waste. A little time spent learning chemical safety rules prevents contamination and keeps everyone safe. Even the cleanest researchers get blindsided when old chemicals get mishandled or thrown out the wrong way. Good storage today means fewer problems tomorrow.
Every researcher at some point faces the classic lab headache: a powder refuses to mix, clumping at the bottom of the glass instead of turning into a clear solution. N-(2-Aminoethyl)maleimide trifluoroacetate salt often finds its place on lab shelves, especially in bioconjugation and protein labeling work. Of course, the main question: does it dissolve in water, or do you have to start thinking up alternative solvents?
Having handled this molecule in a few protein modification experiments, I can say the relief is real—N-(2-Aminoethyl)maleimide trifluoroacetate salt actually dissolves well in water. Factually, many suppliers list it as "freely soluble" or “highly soluble.” At normal concentrations up to 100 mM, most see it dissolve within minutes. Some gentle swirling helps; no need for high temps or fancy tricks. This ease comes down to the trifluoroacetate counterion, which tends to enhance water solubility compared to simpler forms like the hydrochloride.
Soluble reagents save time, reagents, and glassware. Take protein labeling, for example. If the coupling agent clings to the bottom or stubbornly floats as a cloud, conjugation often fails. Water-soluble N-(2-Aminoethyl)maleimide trifluoroacetate saves researchers from those headaches, letting them add their reagent and move on with the experiment.
Solubility isn’t just a box to tick on a protocol. Poorly dissolved compounds—especially in sensitive biochemistry—cause inconsistent results. Clumping reduces the available reactive sites, so some batches over-label, others hardly label at all. Standardization matters much more in experiments where reproducibility stands central, like antibody-drug conjugates or fluorescence tagging.
Peer-reviewed sources back up water solubility claims. As far back as the early 2000s, several protein modification protocols used this salt directly in phosphate-buffered saline, achieving clear solutions and good reaction yields. Integrated DNA Technologies, Sigma-Aldrich, and Thermo Fisher product information reflect these observations—this salt wants to be in water, not stuck in clumps or swirled in DMSO.
Labs working with water-sensitive proteins sometimes run into stray precipitation, but that's usually from the protein, not the maleimide salt. If any trouble pops up, researchers often try adjusting the concentration, using slightly warm water, or switching to a gentle buffer. Acidic pH promotes stability, another plus for the trifluoroacetate form, since the maleimide ring stays reactive.
A lot of people rush new reagents into water out of habit, but it pays off to check the datasheet and consult experienced colleagues. If a powder refuses to dissolve, never force it with too much heat or strong solvents unless you know the consequences. The trifluoroacetate can make aqueous solutions acidic, so pH testing isn’t a bad idea, especially right before use.
Using well-dissolved reagents reduces the exposure risks of airborne powders and cuts down on failed reactions—a win for everyone, from big research groups to students grinding out their thesis experiments. In the world of protein chemistry, solubility isn’t just convenience; it means fewer mistakes, reproducible data, and stronger publications.
Stepping into any research lab, people quickly find out how much a small impurity can throw an experiment off course. With something like N-(2-Aminoethyl)maleimide Trifluoroacetate Salt, purity isn't just a number on a sheet. It shapes results and influences safety. Researchers lean heavily on this compound when crosslinking proteins, labeling biomolecules, or building new bio-conjugates. Small changes in quality ripple through every step that follows.
Scientists consistently turn to specifications near ≥95% purity for this salt, especially when using it in biochemistry or pharmaceutical work. The reason? Anything lower opens the door to unpredictable results. The remaining 5% can include moisture, residual solvents, or even chemical by-products. Left unchecked, these trace bits tweak reactions, block crosslinking sites, or muddy analytic readings.
For reference, Sigma-Aldrich, Thermo Fisher, and other big chemical suppliers list purity standards above 95% for N-(2-Aminoethyl)maleimide Trifluoroacetate Salt. Their product data sheets back this up. With high-stakes work — like clinical studies or diagnostics — researchers reach for lots running closer to 98% or higher. Not because regulations force their hand, but because they’ve learned (often the hard way) about the price of shortcuts.
Some researchers, myself included, have tried to cut costs with slightly lower-purity reagents. Those experiments produced cloudy bands on gels, peaks out of nowhere in LC/MS traces, and inconsistent coupling in protein modification. Reproducibility suffered every time. Purity goes beyond appearances. It boosts confidence, lets teams build on each other’s work, and shortens troubleshooting time. Given today’s pressure for transparency and validation, no lab can afford to gamble.
Just taking a supplier’s certificate at face value can be risky. Even reputable brands occasionally ship out-of-spec material. Handy tools like NMR, HPLC, and mass spectrometry help confirm what’s inside the bottle. Drying salts under vacuum removes moisture, but chemical impurities stick around unless production and purification match or beat those 95% thresholds. People working in regulated spaces double-check batches before adding them to a publication or a drug project.
In recent years, more teams push suppliers for full impurity profiles, not just a single purity number. Knowing what makes up that final 5% helps in troubleshooting and record-keeping. This builds trust up and down the research chain.
Some labs partner closely with suppliers to order custom lots at even tighter specs, especially for critical projects. Training young chemists to carefully read specifications, run cross-checks, and never assume a reagent's quality saves countless hours. Open communication between researchers and manufacturers opens doors for improvements in production and transparency.
In my experience, every extra point of purity saved time, money, and headaches. Setting the bar at ≥95% reflects more than just a best practice — it reflects wisdom earned through experience, error, and shared stories between researchers committed to stronger and more reliable science.
| Names | |
| Preferred IUPAC name | 2,5-dioxo-1-pyrrolidinyl)ethanamine trifluoroacetate |
| Other names |
N-(2-Aminoethyl)maleimide TFA 2-[(Maleimidomethyl)amino]ethanamine trifluoroacetate N-(2-Aminoethyl)maleimide trifluoroacetate N-(2-Aminoethyl)maleimide TFA salt |
| Pronunciation | /ɛn tuː əˈmiːnoʊˌɛθəl məˈleɪɪmaɪd traɪˌflɔːroʊˈæsəteɪt sɔːlt/ |
| Identifiers | |
| CAS Number | 112568-58-4 |
| 3D model (JSmol) | `3D37A04301` |
| Beilstein Reference | 124969-73-3 |
| ChEBI | CHEBI:139506 |
| ChEMBL | CHEMBL4169157 |
| ChemSpider | 149371 |
| DrugBank | DB16371 |
| ECHA InfoCard | 03b1161d-7a95-4aa1-a03a-760c827465d9 |
| EC Number | NA |
| Gmelin Reference | 109285 |
| KEGG | C05594 |
| MeSH | D000544 |
| PubChem CID | 135659522 |
| RTECS number | UU1400000 |
| UNII | 9B7O2D76I8 |
| UN number | UN2811 |
| CompTox Dashboard (EPA) | DTXSID20866945 |
| Properties | |
| Chemical formula | C6H8N2O2·C2HF3O2 |
| Molar mass | 317.21 g/mol |
| Appearance | White to off-white solid |
| Density | 1.432 g/cm³ |
| Solubility in water | Soluble in water |
| log P | -2.3 |
| Acidity (pKa) | 8.0 |
| Basicity (pKb) | 6.9 |
| Refractive index (nD) | 1.470 |
| Dipole moment | 5.5137 D |
| Hazards | |
| Main hazards | Harmful if swallowed, causes skin irritation, causes serious eye irritation. |
| GHS labelling | GHS05, GHS07 |
| Pictograms | GHS07 |
| Signal word | Warning |
| Hazard statements | H302, H315, H319, H335 |
| Precautionary statements | Precautionary statements: P261, P264, P271, P273, P280, P302+P352, P304+P340, P312, P305+P351+P338, P337+P313, P362+P364, P403+P233, P405, P501 |
| LD50 (median dose) | LD50 (median dose): >1000 mg/kg (Oral, Rat) |
| PEL (Permissible) | PEL (Permissible Exposure Limit) information for N-(2-Aminoethyl)maleimide Trifluoroacetate Salt is not established. |
| REL (Recommended) | 100 mg |
| Related compounds | |
| Related compounds |
Maleimide N-Ethylmaleimide N-(2-Aminoethyl)maleimide hydrochloride N-(2-Aminoethyl)maleimide N-(2-Aminoethyl)succinimide Maleimide trifluoroacetate |
