© 2026 Sinochem Nanjing Corporation,
All Right Reserved
Decades ago, biochemical researchers searched for ways to maintain stable pH conditions during experiments. The arrival of Good’s buffers in the late 20th century shook up the lab routine. Among them, CAPS sodium salt carved out a space because common buffers kept failing under harsh conditions of high pH. At that time, scholars and industrial chemists wanted more than a tweak to TRIS or glycine. The synthesis of 3-cyclohexylaminopropanesulfonic acid sodium salt opened paths for biochemists working on high-pH proteins or nucleic acids, especially above the range most typical buffers could handle. This need for stability and specificity kept driving the community to study, refine, and produce CAPS-Na at higher purities, for both research and manufacturing.
Think of CAPS-Na as one of the unsung heroes on a molecular bench. Its sodium salt form dissolves in water more readily than the free acid, making it a staple in labs that push the envelope with enzymes and proteins sensitive to pH swings. Several companies now offer CAPS-Na in research and pharmaceutical grades because the demand hasn’t slowed down. The main users? Those running protein sequencing, chromatography, and enzyme assays, where robust pH control is key.
Sitting in a white crystalline powder or granule, CAPS sodium salt carries a molecular weight near 279 grams per mole. The chemical structure features a cyclohexylamine head hooked to a propanesulfonic acid tail, which lends water solubility after neutralization with sodium ions. Researchers value its pKa of about 10.4, since this sits closer to alkaline values where many other buffers fade. It holds up well at high temperatures, resists degradation, and barely absorbs in UV light, so photometric assays stay clean.
Reliable CAPS-Na sources label purity above 99%, with testing for metal ions, moisture, and dust. The forward-thinking producers often display batch-to-batch consistency, noted with lot numbers and rigorous quality checks. Storage advice leans toward cool, dry shelves, away from volatile solvents, as moisture can clump up powders over time or skew analytical balances. Proper labeling marks not just identity and quantity, but also safety warnings, expiry dates, and traceability information, important for regulatory compliance.
Manufacturing CAPS sodium salt begins with synthetic cyclohexylamine and 1,3-propanesultone. The reaction calls for a solvent—often water or alcohol—and temperature control to steer the sulfonation, locking the sulfonic acid to the propyl chain. Neutralization comes next, where sodium hydroxide brings the compound to its final salt form. Following filtration and crystallization, the crude product gets purified through repeated washing, drying, and sometimes recrystallization, especially for high-end applications in biochemistry. The procedure sounds simple, but small changes in reaction time, temperature, or starting materials can shift the quality, so experienced chemists keep a close watch on every batch.
CAPS-Na doesn’t just buffer; it can play a part in chemical derivatizations. Its amine group reacts with acylating or alkylating agents, allowing scientists to tack on functional groups for conjugation or create derivatives tailored for specific binding studies. The sulfonate group, anchored to the cyclohexyl side, holds steady in most reactions, adding a layer of reliability in synthetic or analytical routes where other buffers can interfere or break down under strong bases.
CAPS sodium salt goes by a few aliases. Literature sometimes refers to it as N-cyclohexyl-3-aminopropanesulfonic acid sodium salt, or more simply, CAPS-Na. Chemical suppliers use catalog codes, but researchers stick with CAPS-Na or its longer chemical name in published protocols. Recognizing these names matters for avoiding mix-ups, especially since closely named analogs—like CHES or MES—behave differently in the lab.
Handling chemicals brings a sense of caution. CAPS sodium salt ranks low on acute toxicity charts, but laboratory rules mean gloves and goggles join the mix. Safety data sheets point out that contact with eyes or prolonged skin exposure may trigger irritation, so even seasoned staff avoid shortcuts. Spilled powder sweeps up with minimal dusting, and water washes away small remnants. Disposal: authorities expect residues to go into designated chemical waste channels, not down public drains, to avoid environmental contamination.
Biochemistry texts and journal articles place CAPS sodium salt at the center of protein sequencing procedures, specifically Edman degradation. Peptide chemists rely on its buffer capacity in high-pH zones, essential for trypsin digestion or isoelectric focusing. Electrophoresis gels for separating proteins by charge also use CAPS, where consistent pH avoids smeared bands or misinterpreted results. In industry, manufacturers of diagnostic kits and biotherapeutics keep CAPS sodium salt in the buffer arsenal because of its thermal stability and low interference with major biological reactions.
The R&D world keeps prodding the boundaries of CAPS-Na use. Structural biologists tinker with novel buffer systems by pairing CAPS with other stabilizers, seeking improved shelf life for purified enzymes or antibodies. Analytical chemists push for ever-purer batches with minimum contaminants, so background interference falls below detection. New methods for synthesizing CAPS sodium salt now explore greener chemistry—cutting down on waste and hazardous intermediates, especially as sustainability rises up the priority list for chemical manufacturers.
Toxicologists have not flagged CAPS sodium salt as especially dangerous in routine laboratory concentrations. Acute exposure studies show low toxicity in animal models, with high doses needed for harmful effects. Environmental research reviews its breakdown and persistence, concluding that its sulfonic acid moiety lowers bioaccumulation risk. Still, the rise of tighter environmental regulations encourages users to monitor waste and consider alternatives for large-scale disposals. Chemical safety committees continue to review emerging data, staying ready to update industrial hygiene protocols in response to new findings.
The surge in biotechnology and therapeutics leaves no slack for buffers that drop reliability. CAPS sodium salt stands to become even more crucial as large-scale protein purification shifts toward automation and integrated diagnostics call for pinpoint reproducibility in every buffer lot. Vendors are likely to offer custom blends, higher grades, and cleaner synthesis routes. Researchers in emerging fields such as biopharmaceuticals, high-throughput screening, and single-molecule analysis keep seeking robust buffers for challenging assays. As governments push for greener, cleaner chemistry, production will likely see expanded use of renewable feedstocks or process intensification. Buffer technology keeps growing at the edges, and CAPS sodium salt, often invisible outside the lab, remains one of the platforms science leans on for tough experiments and emerging medical tests.
3-Cyclohexylaminopropanesulfonic Acid Sodium Salt, best known by its short name CAPS-Na, holds a specific spot on the chemical shelves of research labs. Most scientists recognize it as a buffering agent, a compound designed to keep environments at the perfect pH—usually in the range of 9.7 to 11.1. This might sound mundane, but holding a stable pH matters more than most think, especially in the world of biological research. Reactions between proteins, enzymes, and other biological molecules often depend on pH. Even a small drift can throw off results, waste resources, or undermine years of work.
Protein chemists and biochemists run into unforgiving roadblocks if their solutions wander from the intended pH. Here’s where CAPS-Na shines. Enzyme assays, polyacrylamide gel electrophoresis (SDS-PAGE), and studies of protein structure often require high pH buffers. CAPS-Na offers strong resistance to pH changes in this alkaline zone. Researchers rely on it for Western blot transfer buffers and for tasks like solubilizing membrane proteins, which often fall apart if exposed to acidic or even slightly neutral conditions. I remember the frustration of losing hours of work because something as simple as a buffer failed. Reliable reagents save real time and money in the lab.
CAPS-Na has utility outside protein work, too. It gets a spot in chromatography, the chemical process for separating mixtures. Labs sometimes use it to prepare samples for analytical tools that check for traces of drugs, pollutants, or food allergies. Maintaining a stable pH improves peak resolution and accuracy, which means researchers get readable data without as much background static. Some protocols in the pharmaceutical industry favor CAPS-Na for formulating diagnostic kits. It’s also remarkably soluble in water, which matters every time you’re measuring, mixing, and waiting for powders to clear before moving to the next step.
A research buffer might not seem like much compared to a breakthrough drug or a new piece of technology, but every major scientific achievement rests on good technique and reliable materials. Poor buffer choice can produce false negatives, lead to ruined blots, or even invalidate results that might have taken months to collect. I’ve seen whole projects delayed by inconsistent reagents, where teams had to repeat controls or redesign experiments. Financial costs rise quickly; research money should go toward advancing science, not repeating the basics.
Supply quality forms another challenge. Labs count on stable, pure chemicals. If providers cut corners or ship buffers with unlisted contaminants, experiments can fail for reasons no one suspects. More transparent sourcing helps; so does regular third-party testing. Education matters, too. Not every student or new researcher understands buffer chemistry right away, so recipes and protocols need to be clear. Many busy labs share standard operating procedures for buffer prep, removing guesswork, and building confidence among newcomers. The right buffer does more than help molecules behave—it frees up researchers to tackle the big questions without sweating the basics every week.
CAPS-Sodium Salt shows up in many labs focused on biochemistry, molecular biology, and analytical work. It’s a buffer with a strong grip on pH at the higher side—useful for protein and enzyme work where a steady environment turns small differences in results into big changes in research direction. As with any chemical, the way you store CAPS-Sodium Salt figures into its reliability.
Most CAPS-Sodium Salt arrives as a dry solid. Moisture in the air gets drawn into this powder, turning it clumpy and sometimes even affecting its strength. Humidity is a chemical’s enemy. That’s why the advice from major suppliers and generations of lab veterans lines up—store CAPS-Sodium Salt in a tightly sealed container with a clear label. Tucking it away in a cool, dry spot out of direct sunlight keeps it dependable. For long-term use, keeping it in a refrigerator (2–8°C) goes a step further, especially if the lab battles heat and moisture most of the year.
Sloppy storage can introduce trouble. If CAPS-Sodium Salt takes on water, your weighing turns inaccurate, pH buffering isn’t right, and the science goes sideways. I’ve seen projects drag for weeks, chasing the source of unexpected pH drift, only to discover a streaky desiccant pack and lid left loose in the bottle. Storing chemicals right seems small, but one quick grab for an unsealed bottle can cost precious sample, time, and funding.
CAPS-Sodium Salt doesn’t handle light well for extended periods either. UV rays creep through some plastics and glass, slowly chewing up the quality of even top-grade reagents. Dark bottles can slow this down. That’s one trick I picked up from a mentor who curated supplies as carefully as his data.
Many take shortcuts—maybe it feels harmless pouring straight from the container or skipping gloves for a quick dose into a beaker. Over time, this carelessness risks contamination or accidents. Sodium salts, including this one, benefit from a clean spoon or spatula each time, and always resealing after use. Clean hands and safety glasses make more sense than ever in a crowded, fast-moving workspace.
Safety data sheets put it in clear language—protect the substance from moisture, store in a cold environment, keep away from acids and incompatible chemicals. These aren’t just legal checklists; they protect repeated results and everybody working around the bench.
Labs run at different paces. Labels peel, freezers overflow, and new staff may overlook the need for fresh desiccant or the right container. It pays to build habits—regularly check expiration dates, rotate stocks, and inspect seals. One way to get everyone up to speed: short refresher notes where chemicals live, and a rough calendar for scheduled checks. Combining this with a shared digital log can keep mistakes down and accountability up.
It comes down to respect for the material and the experiments that follow. Keeping CAPS-Sodium Salt cool, dry, and away from light and acids means fewer unwelcome surprises, steadier data, and more confidence that the next box you open matches the label every time.
Working in the lab over the years, buffers stay at the core of every experiment that involves proteins, enzymes, or any pH-sensitive materials. Let’s put the spotlight on CAPS-Sodium Salt. This buffer doesn’t turn up in every undergrad experiment like phosphate or Tris, but in the world of biochemistry and protein purification, it owns a unique spot. For scientists adjusting pH in more alkaline ranges, CAPS-Sodium Salt brings reliability few others match.
CAPS-Sodium Salt steps in with a mean buffering range between pH 9.7 and 11.1. It isn't just about hitting a specific number on the pH meter. Many proteins demand a stable, alkaline home above 9, especially when folks are after dephosphorylation studies, electrophoresis on polyacrylamide gels, or research with enzymes that only function well at higher pH. Using plain water can shift pH just by letting CO2 from the air dissolve in the buffer. A system like CAPS supports an environment where results stay consistent across multiple runs.
Look at Western blotting, for example. Working with proteins that need to keep their structure at higher pH means some of the common choices just can’t hold the fort. CAPS-Sodium Salt meets this need, helping maintain pH where other buffers fall short. If you've ever had a critical protein lose function or fail to transfer during electroblotting, a buffer in the wrong range probably played a role.
Protein stability isn’t just a technical footnote. Poor buffer choice can cause samples to fall apart or lead to misleading data. The buffering zone for CAPS-Sodium Salt guards precious protein samples against sudden pH changes, blocking deactivation or precipitation. Researchers trust this buffer to shield proteins during purification, enzyme reactions, and even in cold storage.
Using a buffer in the wrong zone doesn’t only risk wasted time. It means burning through rare reagents, waiting for equipment, and slogging through avoidable troubleshooting. In research labs pressed for funding, misuse of buffers really translates to real-world losses — dollars, energy, and sometimes irreplaceable samples vanishing down the drain.
Experiments need reproducibility. This isn't about just following a protocol. It’s about guaranteeing the same pH environment every single time, no matter who runs the test or which batch of chemicals rolls off the truck. CAPS-Sodium Salt, with its alkaline range, saves research teams from week-to-week troubleshooting. The importance grows in large-scale manufacturing of pharmaceuticals, where mishaps can top six figures and delay clinical trials.
Using equipment that measures pH well past 10 clears up any doubts. It makes a difference whether the pH meter gets calibrated regularly or whether folks just take a reading and hope for the best. Keeping the buffer tightly capped and stored at the right temperature helps keep it within its promised range. Switching to freshly prepared CAPS-Sodium Salt rather than reaching for a bottle that’s been open for months keeps variability at bay.
Training new team members to check the buffer’s actual pH before each experiment can eliminate small mistakes that snowball into big headaches. Choosing reagent-grade CAPS-Sodium Salt and documenting outcomes from each batch lines up with what good research demands. It boils down to this: strong basic buffers like CAPS-Sodium Salt support the backbone of accurate, repeatable science where alkaline conditions must be maintained for hours or even days.
Researchers don't just grab the nearest buffer off the shelf. Buffer choice shapes everything from enzyme stability to protein structure. CAPS-Sodium Salt, or N-cyclohexyl-3-aminopropanesulfonic acid sodium salt, turns up on a lot of reagent lists—not just for convenience, but because it offers a measurable window into biological work. Its pH range, covering roughly 9.7 to 11.1, sits up in the alkaline zone. That means many classic methods, which run at neutral or slightly basic conditions, step aside for tasks that actually need this higher territory.
In my own lab days, pH control ranked just under pipetting accuracy for impact. Small mistakes with a buffer could throw weeks of work out the window. CAPS-Sodium Salt tends to hold its ground, even in the face of temperature swings or salt spikes. That makes it attractive for protein work, especially for proteins that don’t handle acidic or even neutral environments well.
Experiments focusing on enzyme activity, especially enzymes such as alkaline phosphatases or specific proteases, often depend on pH staying constant above 9. Lots of buffers lose their effectiveness here and start to drift. CAPS-Sodium Salt doesn’t wander off so easily. That saves time and reduces the wild goose chase for sources of experimental error.
Every buffer throws curveballs. CAPS-Sodium Salt avoids many pitfalls seen in more reactive buffers, like Tris. It stays out of most enzyme active sites and resists forming unwanted complexes with transition metals, which turns into a genuine problem for researchers tracking metalloproteins or running assays with metal cofactors.
Some researchers on protein purification trails run into issues with phosphate or other sulfonated buffers wrecking downstream mass spectrometry or blotting. CAPS can present fewer background signals. This can make life easier, though it comes at a higher cost and not every protein likes the high pH.
Cost matters. CAPS-Sodium Salt rarely wins as the budget option, especially for big batches. High-grade material still demands careful storage—moisture absorption ruins batch after batch if containers aren’t tightly sealed. Inconsistent storage leads to unreliable results, so labs can’t afford to get casual about these details.
Another point involves downstream compatibility. Not every detection method tolerates the presence of sodium or the buffer itself. Fluorescent dyes or some colorimetric reagents can fade or shift in high pH, and the presence of CAPS complicates things for labs running older or proprietary detection chemistries. Double-checking compatibility before jumping into a large experiment saves time and resources.
Switching to CAPS-Sodium Salt isn’t just about what’s trendy or new. Its strengths—solid buffering above pH 9, low interference, and proven track record in certain fields—deliver real value for specialty protein work. For routine buffers or conditions below pH 9, other options might serve better, both in cost and performance.
Labs looking to start new projects with complex proteins, or where traditional buffers fail, should give CAPS-Sodium Salt an honest look. Verification in small pilot experiments shows whether the buffer genuinely supports the stability and activity researchers expect. Smart adoption always starts with head-to-head testing, not just reading product claims.
CAPS-Sodium Salt plays a pretty regular role in the daily grind of lab work. Its chemical formula stands as C9H18N3O6SNa, and its molecular weight comes in at about 339.31 g/mol. Anyone handling biological research or analytical chemistry will recognize CAPS for its stability, especially when buffering alkaline solutions. Seeing the numbers attached to this compound tells not only what it’s made of, but also helps predict its behavior across a range of experiments.
Formulas and molecular weights aren’t just for textbook questions. Every scientist heading into the lab needs to know exactly what they’re dealing with. It’s one thing to choose a buffer – it’s another to mix it properly, apply it at the right concentration, and avoid headaches like pipetting errors and ambiguous results. CAPS-Sodium Salt, thanks to its set weight, gives confidence when weighing powder or preparing stock solutions. These details feed right into reproducibility, which stands as the gold standard for science that people can trust. No one wants to run an experiment twice because of a miscalculation caused by a missed sodium ion or a misplaced decimal.
Somewhere along the way, I lost track of how often I’ve worked with buffers for protein research. CAPS straightened out pH levels without fuss when other buffers drifted or let things go weirdly alkaline. Knowing the exact formula meant less worry about ionic strength or compatibility — it took one call to the supplier and a scan of the spec sheet. Getting the molecular weight right also saved time, especially on days with a long to-do list and no extra room for backtracking. I’ve watched new lab members triple-check calculations, sweating over tiny details that could send results sideways. CAPS gave us peace of mind, and that focus on detail paid off every single time a sample didn’t need to go in the trash.
These days, research demands precision. Whether it’s biotech, diagnostics, or academic work, every publication rides on clear, repeatable data. CAPS is popular for protein purification, electrophoresis, and enzyme assays because its sodium salt helps keep things soluble and pH-stable even at higher alkaline levels. If you’re scaling up a process or troubleshooting a stubborn reaction, the numbers behind CAPS guide how much to add, how to mix it, and what to expect in your results. Certainty in the core numbers means less lab waste, fewer failed assays, and faster progress from question to answer.
There’s a bigger picture here. Accurate chemical information builds a culture of good science from training students up to global collaborations. If labs share formulas and molecular weights openly, quality goes up across the board. Researchers lose less time double-checking dubious reagent lists and more time solving real-world problems. Good records in one lab turn into reliable protocols for the next, and nobody scrambles for missing details halfway through a time-sensitive project.
Labs and suppliers could do more to make data on chemical reagents like CAPS-Sodium Salt clearer and easier to find. Digital inventory systems, open-access databases, and accurate labeling might seem simple, but every one counts. For anyone working hands-on, this information isn’t just a scientific detail — it’s the first step toward solid, defensible results that move the field forward.
| Names | |
| Preferred IUPAC name | Sodium 3-(cyclohexylamino)propane-1-sulfonate |
| Other names |
CAPS sodium salt N-Cyclohexyl-3-aminopropanesulfonic acid sodium salt 3-Cyclohexylaminopropane-1-sulfonic acid sodium salt N-Cyclohexyl-3-aminopropanesulfonate sodium salt |
| Pronunciation | /ˈθriː saɪkloʊˈhɛk.sɪlˌæm.ɪ.noʊ.proʊˈpeɪnˌsʌlˈfɒn.ɪk ˈæs.ɪd ˈsoʊ.di.əm sɔlt/ |
| Identifiers | |
| CAS Number | 113589-08-9 |
| 3D model (JSmol) | `3DModel: "data:JSmol/A" "Molecule=CC1CCCC(C1)NCCCS(=O)(=O)[O-].[Na+]"` |
| Beilstein Reference | 3595582 |
| ChEBI | CHEBI:91248 |
| ChEMBL | CHEMBL1231659 |
| ChemSpider | 22995094 |
| DrugBank | DB11095 |
| ECHA InfoCard | ECHA InfoCard: 100.300.104 |
| EC Number | 74144-97-1 |
| Gmelin Reference | 100333 |
| KEGG | C19664 |
| MeSH | D08.811.277.040.330.610.250.100 |
| PubChem CID | 23665772 |
| RTECS number | TN7850000 |
| UNII | T3U4OOS5L4 |
| UN number | Not regulated |
| CompTox Dashboard (EPA) | DTXSID4014295 |
| Properties | |
| Chemical formula | C9H18NNaO3S |
| Molar mass | 343.46 g/mol |
| Appearance | White crystalline powder |
| Odor | Odorless |
| Density | 1.204 g/cm³ |
| Solubility in water | soluble |
| log P | -2.6 |
| Acidity (pKa) | 9.6 |
| Basicity (pKb) | 10.4 |
| Refractive index (nD) | 1.490 |
| Viscosity | 8-18 cP (1% in H2O, 25°C) |
| Dipole moment | 7.8 D |
| Thermochemistry | |
| Std molar entropy (S⦵298) | 291.5 J·mol⁻¹·K⁻¹ |
| Std enthalpy of formation (ΔfH⦵298) | -1102.8 kJ/mol |
| Std enthalpy of combustion (ΔcH⦵298) | -1417.8 kJ/mol |
| Hazards | |
| Main hazards | May cause respiratory irritation. May cause eye, skin, and respiratory tract irritation. |
| GHS labelling | GHS07 Warning |
| Pictograms | GHS07 |
| Signal word | Warning |
| Precautionary statements | Precautionary statements: P261, P264, P271, P272, P280, P302+P352, P305+P351+P338, P312, P321, P332+P313, P337+P313, P362+P364 |
| NFPA 704 (fire diamond) | NFPA 704: "Health: 1, Flammability: 0, Instability: 0 |
| Flash point | >100°C |
| LD50 (median dose) | LD50 (median dose): >5000 mg/kg (Rat) |
| PEL (Permissible) | Not established |
| REL (Recommended) | 10 mg/m³ |
| IDLH (Immediate danger) | NIOSH does not list an IDLH for 3-Cyclohexylaminopropanesulfonic Acid Sodium Salt (CAPS-Na). |
| Related compounds | |
| Related compounds |
HEPES MES PIPES MOPS TES |
