4-Morpholinopropanesulphonic Acid arrived on the scene just as modern chemistry began pushing into new frontiers that demanded reliable, stable buffers for biological and chemical systems. Scientists in the late twentieth century spent a lot of energy wrestling with unpredictable results from common buffering agents. After a string of discoveries, researchers homed in on compounds like 4-Morpholinopropanesulphonic Acid—often called MOPS. It didn’t just offer a new chemical; it gave labs a chance for tighter control over experiments, especially those requiring pH levels to stay put across a wide range of temperatures. This achievement changed the way biochemists handled proteins and nucleic acids and opened new doors for consistent research outcomes.
MOPS lives in the world of organic buffer solutions. You find it in powder or crystalline form, easy to store and dissolve. Its defining property is acting as a buffer, holding pH levels steady during procedures like electrophoresis and protein purification. Over decades, it has taken a firm spot on the shelves of life science labs, biotech companies, and pharmaceutical manufacturers. It stands up to the notoriously finicky nature of biomolecules, proving itself again and again in tough experimental settings.
MOPS presents itself as a white crystalline solid with a mild, neutral odor, melting at about 288°C (550.4°F). The compound is soluble in water yet holds its structure against common organic solvents. It stays robust over a range of temperatures, and with a pKa of 7.2 at 25°C, it makes a natural fit for biological applications close to physiological pH—think blood serum, standard cell cultures, and enzyme reactions. Chemical stability here isn’t just a buzzword; it means fewer interruptions during long experiments and less time troubleshooting.
Labs rely on MOPS provided in assay grades reaching purity levels above 99%. Labels don’t just list the product’s name; they show details like batch number, lot tracking, and expiration date, supporting both traceability and safety. Some suppliers offer buffered concentrates or tablets, which makes preparation straightforward. Every canister should have hazard information and storage recommendations. For serious research, you want these numbers: molecular weight at 209.26 g/mol, CAS number 1132-61-2, and a chemical formula of C7H15NO4S.
Creating MOPS typically follows a sequence that begins with morpholine and 1,3-propane sultone in a basic environment. The reaction is straightforward by chemistry standards yet needs careful temperature control and precise measurements. Afterward, purification—often through crystallization—separates out impurities, guaranteeing high purity. Each step is standard practice in industrial and academic settings, passed down through detailed protocols to avoid unexpected surprises at scale.
In the lab, MOPS is known for not interfering with proteins, nucleic acids, or the bulk of reagents in standard biology or chemistry workflows. Its own structure holds up against most electrophoresis conditions and doesn’t break down easily in the presence of common reducing agents, UV light, or mild acids and bases. Some researchers tweak the molecule to create new analogues for studies that demand unique buffering ranges or solubility tweaks. MOPS reacts predictably under standardized synthetic routes, letting chemists experiment without re-learning its behavior every time.
MOPS hides behind a whole parade of names, much like many popular chemicals. Its synonyms include 3-(N-Morpholino)propanesulfonic acid, and suppliers often use catalog codes like M1254 or M8889. No matter the alias on the label, ingredients and composition match specifications across borders and brands, from Sigma-Aldrich to local research suppliers. It’s up to the end-user to confirm what’s inside the bottle meets requirements, a step everyone gets in the habit of checking before opening a new supply.
Handling MOPS goes a lot like most neutral organic acids. Gloves, goggles, and good ventilation are standard protective measures. Safety data sheets back up these practices, warning about eye and skin irritation and advising to avoid direct inhalation. In storage, dry containers and cool, stable environments keep the chemical in top condition, away from strong oxidizers. Waste disposal leans on standard protocols—diluting solutions with water and neutralizing before release into approved systems. Consistent quality checks in production plants and routine monitoring during use cut down on risks both to researchers and the environment.
MOPS handles pH-sensitive conditions too tricky for older buffers. Molecular biologists use it in RNA and protein electrophoresis because it guards against degradation. In cell culture, it keeps conditions steady, acting in the background but making a major difference to cell health and reproducibility. Diagnostic kit manufacturers and pharmaceutical formulators have pulled MOPS into workflows for everything from rapid-test strips to therapeutic protein formulations. In education, it helps students see the difference proper buffers make, showing real results rather than muddy, unpredictable data. I’ve watched new scientists struggle with buffers that drift off-target; swapping in MOPS can turn a frustrating experiment into a reliable one. Its presence in every corner of biology, medicine, and teaching reminds anyone in science how much small changes in technique matter.
A lot of current research centers on making MOPS cheaper, faster to produce, and even greener by reducing the energy and solvents demanded in its manufacture. Multinational projects explore buffer combinations that lengthen the shelf life of biologics—a challenge as modern drugs become more complicated and delicate. Downstream, there’s interest in custom derivatives for applications outside biochemistry, like chemical sensors and diagnostic agents. Academic labs propose tweaks to the MOPS structure to get even tighter pH control, always looking for new ways to deal with old experimental headaches. Before MOPS, many labs gave up on tricky reactions; with better buffers, they keep pushing boundaries instead.
Reviews published over decades haven’t shown strong toxicity linked to MOPS in mammals or standard model organisms when used at regular concentrations. Recent studies keep a close watch on long-term environmental buildup, but so far, the compound passes regulatory screens if handled and disposed of properly. Still, no chemical gets a free pass. Some research notes potential effects on aquatic life, highlighting the need for solid disposal routines and tighter monitoring during large-scale applications. I make it a point to review new data before using any chemical in the lab—relying on safety doesn’t work if safe limits change without warning.
Demand for highly precise, reliable buffers grows every year as research dives deeper into molecular biology, genetic engineering, and biologic therapeutics. Some startups and established chemical giants are racing to design more sustainable syntheses, using renewable feedstocks or low-impact processes. As personalized medicine keeps expanding, reliable buffer systems like MOPS are turning into unsung heroes, holding together everything from CRISPR experiments to mass-market biopharmaceuticals. My own experience moving between academic labs and biotech companies has shown that simple, dependable buffer systems carry massive weight behind the scenes. MOPS and its coming generations look set to remain critical, as more researchers chase innovations needing stability, safety, and clarity from their core reagents.
Scientists often puzzle over how to keep chemical reactions steady. pH swings can push things off the rails, mess up experiments, or even ruin entire research batches. That’s where 4-Morpholinopropanesulphonic Acid, usually called MOPS, steps in. MOPS keeps the environment stable for reactions, much like keeping an oven at the right temperature for baking. MOPS has been a mainstay in labs, thanks to its reliability.
Decades in university labs have taught me that MOPS isn’t just ordinary. Folks like me counted on it for pH buffering, especially in the range around 7, the sweet spot for many enzymes and biological molecules. This helped during sensitive protein studies, where slight changes could mean the difference between a clear result and a failed trial. With MOPS, scientists trust that proteins and nucleic acids don’t fall apart because of random shifts in pH.
Biochemistry teaches us that buffers must play by strict rules. The wrong environment spoils the game. MOPS became the answer for DNA and RNA work, thanks to its low tendency to react with other chemicals and not interfere with results. Research groups use it in gel electrophoresis, which sorts tiny pieces of genetic material, helping researchers map genes or screen for mutations. In this way, MOPS helped speed up early genetic testing and keeps moving the field forward.
When biotechnology scaled up, MOPS stayed important. Drug makers and diagnostic labs mix it into solutions for protein purification. It avoids interactions that could mess up drug formulations. In these settings, sticking to high standards isn’t just about better science—it’s a requirement for safety. Professional experience taught me that MOPS-based buffers bring peace of mind. No one wants to risk unexpected contamination when lives depend on reliable results.
No chemical gets a free pass. MOPS shows low toxicity in typical concentrations, but production and disposal raise questions. Some researchers favor greener chemistry and seek alternatives with less waste or energy involved. Chemical waste from frequent disposal adds up across thousands of labs. It may not hit the news, but proper disposal means partnering with professional waste handlers and finding ways to minimize leftovers. This deserves more attention from lab managers and educators. A bit more training and awareness about waste reduction wouldn’t hurt either.
Simplicity and stability have made MOPS a quiet workhorse for both small research setups and big industry plants. Its role in supporting science behind the scenes remains crucial, even as fields like genetic engineering and diagnostics evolve. Still, the best practice demands ongoing review. Some day, newer buffers might take the spotlight, bringing less environmental impact or even smart adjustment to changing lab needs.
For now, MOPS stands out for its contributions. Reliable tools like this let scientists trust their setups and focus on solving bigger problems. Anyone who handles biological samples should recognize its role and take responsibility for its full life cycle, from bottle to disposal. That’s how research can keep advancing without leaving bigger issues behind.
Most lab folks rely on reliable, stable reagents. One buffer that shows up all over biochemistry and molecular biology experiments is 4-Morpholinopropanesulphonic Acid, or MOPS. It shows up in RNA work, electrophoresis, and protein purification because it keeps pH stable right where people need it. Toss it on a shelf or store it near an open window, and you could wreck its consistency or effectiveness. I remember a time our electrophoresis gels gave inconsistent bands—turns out someone stored the buffer in a cabinet above a radiator. Lesson learned: storage conditions matter more than most people expect.
MOPS stays stable if kept at room temperature, usually around 20-25°C. It’s not a compound that likes extreme swings. High temperatures can lead to slow breakdown or unexpected reactions, causing color changes or even precipitation. It can start off as a white or off-white solid, but humidity and heat leave clumped masses or introduce contamination. Freezing brings no real benefit—sometimes it causes condensation. Labs I’ve worked with keep MOPS powder tightly sealed in the original bottle, tucked away inside a cool, dry cabinet, far from direct sunlight. I’d put it right next to the Tris and EDTA, never in the fridge, never on the benchtop at a south-facing window.
Another thing that ruins a lot of good reagent is water in the air. MOPS draws moisture. In a humid lab (think mid-summer, leaky A/C), a jar left open absorbs water, turns into a sticky mess, and even shifts weight. If you’re weighing out for a buffer, you end up with more water content and less reagent per gram than you planned. The batch gets unpredictable. Seal it up tight after scooping, preferably with a desiccant pack tossed in for backup. I use those little silica gel bags from empty electronics boxes—they work just fine in the chemical storage space.
Placement of storage matters. Sunlight and constant fluorescent light can affect chemical stability over time, especially if original packaging is translucent. Avoiding clear glass jars helps. Toss colored or opaque bottles in the cabinet. Before we adopted better light control in the chemical store, we spotted subtle shifts in buffer performance during summer months—some correlation with storage conditions showed up after troubleshooting.
Once you’ve made up a MOPS solution, the storage game changes a bit. Aqueous solutions sit best at 2-8°C, tightly capped to keep out microbial contamination and air. If you leave the solution too long or use tap instead of pure water, you might notice fogginess or contamination after a week or so. A fresh batch always beats rolling the dice on an old one. Label the bottle with the date mixed and watch out for any changes in appearance or smell—cloudiness, color changes, or floating specks mean something’s off.
No fancy storage gear required. Common sense matters far more than high-tech fridges or alarms. Keep solid MOPS dry, shaded, sealed up. Keep solutions chilled and clearly labeled. People sometimes forget these basics, but real science comes from paying attention to the daily details. Inexperienced lab members notice faster troubleshooting when habits are consistent. Stocking up on small, fresh batches instead of years-old powder helps, too. Reliable storage delivers consistent, repeatable experiments, avoiding headaches and wasted time down the line.
Many chemists, both in research and industry, rely on buffers to carry out precise work with proteins, enzymes, and even DNA. 4-Morpholinopropanesulphonic Acid, often shortened to MOPS, comes up often in this context. The molecular weight of MOPS stands at 209.26 g/mol. That figure isn’t just a tidbit for trivia. It tells researchers how much of the powder to weigh out so solutions match the concentrations needed for accurate experiments.
In the lab, making mistakes with concentration throws off results. Missing a decimal on the molecular weight, even by a small amount, causes buffer strength to shift. A 1M solution means one mole per liter, so knowing the exact g/mol value prevents waste and repetition. Too high a concentration? Enzyme rates change. Too low? Proteins might misfold. Good science builds measure by measure, not by shortcuts.
If you’ve ever prepped a protein gel and spent hours watching faint bands instead of clear ones, maybe you met the result of an incorrect buffer. MOPS buffers help maintain a close-to-neutral pH, ideal for delicate proteins. The buffer’s effectiveness comes from its molecular structure—morpholine ring giving it versatility, sulfonic acid arm granting solubility. Precise molecular weight ensures experiments aren’t battling hidden errors from the start.
Quality control in chemicals doesn’t just mean fancy packaging. It’s the confidence that a reagent behaves identically from batch to batch, year to year. Chemists know that 209.26 g/mol comes from careful calculation, adding up atomic masses:
MOPS shows up in cell biology, biochemical reactions, and even diagnostic work. Some labs stick with Tris, others opt for phosphate. MOPS stays relevant because of its steady pH range—making it a staple for protein electrophoresis. Knowing the number for its molecular weight trims out room for ‘good enough’ measuring, giving confidence to new students and senior scientists alike.
With supply chain changes and the rise of generic chemical suppliers, labs face more inconsistent lots. Some receive bottles from unfamiliar brands, trusting what’s typed onto the label. Confirming molecular weight independently has become almost a safety check. Accrediting agencies press for labs to verify figures through independent calculation and supplier documentation. A lot of problems in reproducibility can be traced to sloppiness with such basics.
No one wants failed experiments or mysterious inconsistencies. Labs hungry for solid findings begin with small steps: weighing out 209.26 grams of MOPS per mole, dissolving with care, and logging each detail. Mistakes at the weighing stage echo through every blot and assay. In my own work, taking five extra minutes to recheck the molecular weight has saved weeks of troubleshooting contested results. Science rewards careful groundwork, and that traceable number—209.26 g/mol—keeps results honest.
In lots of science labs, you find 4-Morpholinopropanesulphonic Acid — people call it MOPS buffer. Chemists or biologists add it to reactions needing a steady pH. Some folks assume “buffer” means “safe,” but that label downplays risks that come with any chemical, even ones used for decades. Sitting in front of a cluttered bench, researchers like me sometimes treat MOPS with the same casualness as table salt. That’s not ideal.
MOPS in white crystalline form rarely gives off much dust, yet working in a dry room for years, I’ve wiped fine powder from my gloves and coughed more than once if I skipped a mask. The chemical by itself isn’t considered cancer-causing or a big mutant-booster, but some reports from the European Chemicals Agency still urge care. Skin or eye contact leads to irritation. If you swallow or inhale large amounts, there’s a risk of stomach pain or lung irritation. Nothing benign there. I’ve had lab partners get rashes after a spill, and we always rinse fast to head off trouble.
You don’t run screaming from MOPS, but smart users respect it. Gloves, goggles, a coat—those never seem optional after you see a labmate deal with a splash. Ventilation lowers risk, and good housekeeping helps too. Leaving residue on benches or hoods sets up not only you but the next guy for exposure. OSHA regulations don’t flag it as a top-tier hazard, but nobody shrugs off a chemical burn, even if it comes from something outside the “dangerous” lists. Up-to-date safety data sheets in every supply room keep people sharp and honest. These documents spell out just what each chemical can and can’t do to your body. On busy days, someone always points you to the file cabinet when they spot a new face in the room.
People sometimes wash unused MOPS down the drain. That’s bad idea territory. Water treatment plants aren’t designed to break down every lab chemical. Disposing of small volumes of MOPS in a way that keeps it out of streams keeps wildlife safer. Some studies point to the harm of chronic low-level chemicals in aquatic life. Following institutional rules or city disposal codes shows respect for neighbors and nature, not just for lab rules.
Like any lab regular, I’ve watched procedures tighten over the years. Schools want higher standards. Laboratories build in better training. Experts suggest digital tracking of each chemical, so you know what’s on hand and how to handle it. Manufacturers work to update safety information. These small shifts add up. People think twice before grabbing a bottle. Expect new users to pause for training, read up on the substance, and treat all chemicals with a basic respect, even ones that have earned a “low hazard” mark. Complacency grows accidents. Vigilance keeps accidents rare, and good habits help every scientist go home safe.
Preparing a buffer solution seems routine in most labs, but 4-Morpholinopropanesulphonic acid, often called MOPS, pulls its own weight in reliability for biochemistry and molecular biology. MOPS keeps the pH in check, which matters a lot for experiments involving DNA, RNA, or proteins. The stuff comes as a white powder, easy to store, and weighs in at a relatively neutral smelling substance, not nearly as intimidating as it sounds on paper.
No magic wand needed, yet skipping corners doesn’t pay off either. Grab a calibrated pH meter, high-purity water—like Milli-Q or deionized water—and an accurate scale. MOPS acts as a zwitterionic buffer, so it plays nicely within the pH range from about 6.5 to 7.9. Depending on whether you need the ionic strength tweaked, sometimes sodium chloride helps. For those running electrophoresis or working around sensitive enzymes, keep everything squeaky clean and use gloves. One stray contaminant sends you back to square one.
Start by weighing out the amount of MOPS you need for your desired concentration. One common concentration is 10 mM, but labs often use 50 mM or 100 mM depending on their aim. Pour the powder into a beaker with slightly less water than needed for your final volume. Stir until dissolved. Getting lumps? Warm things up a bit—don’t rush it with too much heat, just a gentle nudge if needed.
Adjusting the pH isn’t just poking with some acid or base. MOPS solutions usually need fine-tuning with sodium hydroxide or hydrochloric acid. The target pH varies based on downstream processes. For RNA work, pH 7.0-7.4 often hits the sweet spot. Approach the target slowly, with constant stirring and regular checks on the pH meter. Overshooting can be a pain; adding acid to walk things back can change the ionic background more than planned.
Missteps in making a buffer show up everywhere—shaky results, poor reproducibility, wasted time. In labs I’ve worked, any shortcut in buffer prep led to blotchy gel images or inconsistent yields. A few years back, a colleague skipped the pH check, figuring it would turn out fine. The qPCR results flopped, costing a week’s work. Since then, double-checking pH has saved my own projects from avoidable headaches.
Label every bottle clearly with contents, concentration, pH, and preparation date. Store MOPS solutions in the fridge if unused for longer than a few days, and always use clean pipettes and spatulas. If you see any cloudiness or if the solution smells odd, toss it and make a fresh batch. Repeated freeze-thaw cycles degrade MOPS, so make only as much as needed or split it into aliquots.
Pushed for time and facing an undissolved mess? Use gentle heating and stir bars, but also check if your MOPS came from a trusted supplier. Contamination from tap or unfiltered water often ruins buffer quality; only use high-grade water. For error-prone environments, writing a buffer prep log keeps everyone on track and stops that uncomfortable guesswork from creeping in mid-experiment.
Reliable buffer prep comes down to care and patience. Taking a page from seasoned lab techs, mindfulness at every step shapes good science. Well-made buffers help your science reflect the best of your skills and intentions.
| Names | |
| Preferred IUPAC name | 4-morpholin-4-ylbutane-1-sulfonic acid |
| Other names |
MOPS 3-(N-Morpholino)propanesulfonic acid Morpholinepropanesulfonic acid 4-Morpholinepropanesulfonic acid |
| Pronunciation | /ˈmɔːr.fəˌliː.noʊ.proʊˈpeɪn.sʌlˌfɒn.ɪk ˈæs.ɪd/ |
| Identifiers | |
| CAS Number | 1132-61-2 |
| 3D model (JSmol) | `load =3mop;` |
| Beilstein Reference | 1722181 |
| ChEBI | CHEBI:39050 |
| ChEMBL | CHEMBL1136 |
| ChemSpider | 2154 |
| DrugBank | DB03808 |
| ECHA InfoCard | 03e2a6e0-6f3c-4c33-9149-cd63e8b7cff2 |
| EC Number | '252-162-9' |
| Gmelin Reference | 91906 |
| KEGG | C02341 |
| MeSH | D017929 |
| PubChem CID | 4099 |
| RTECS number | TP3675000 |
| UNII | C21H7B4O9S |
| UN number | UN3334 |
| Properties | |
| Chemical formula | C7H15NO4S |
| Molar mass | 205.24 g/mol |
| Appearance | White crystalline powder |
| Odor | Odorless |
| Density | 1.204 g/cm³ |
| Solubility in water | >1000 g/L |
| log P | -3.2 |
| Acidity (pKa) | 5.3 |
| Basicity (pKb) | 5.87 |
| Magnetic susceptibility (χ) | -6.3·10⁻⁶ cm³/mol |
| Refractive index (nD) | 1.484 |
| Viscosity | Viscous liquid |
| Dipole moment | 7.63 D |
| Thermochemistry | |
| Std molar entropy (S⦵298) | 167 J·mol⁻¹·K⁻¹ |
| Std enthalpy of formation (ΔfH⦵298) | -759.3 kJ/mol |
| Std enthalpy of combustion (ΔcH⦵298) | -5231.6 kJ/mol |
| Hazards | |
| Main hazards | May cause respiratory irritation. Causes serious eye irritation. Causes skin irritation. |
| GHS labelling | GHS07, GHS05 |
| Pictograms | GHS07 |
| Signal word | Warning |
| Hazard statements | H319: Causes serious eye irritation. |
| Precautionary statements | Precautionary statements: P261, P305+P351+P338 |
| NFPA 704 (fire diamond) | Health: 2, Flammability: 1, Instability: 0, Special: - |
| Flash point | Greater than 230°C |
| Lethal dose or concentration | LD50 Oral Rat > 5,000 mg/kg |
| LD50 (median dose) | LD50 (median dose): > 5,000 mg/kg (Rat, oral) |
| PEL (Permissible) | No PEL established |
| REL (Recommended) | REL (Recommended Exposure Limit) for 4-Morpholinopropanesulphonic Acid: "Not established |
| IDLH (Immediate danger) | Not listed |
| Related compounds | |
| Related compounds |
MES buffer HEPES MOPS PIPES TES |
