Monosodium citrate anhydrous didn’t pop up in labs by accident. For over a century, chemists tinkered with citric acid salts to understand how simple tweaks in a molecule could help food stay fresh or make medicines buffer stomach acid. Citric acid itself came from lemon juice before anyone figured out fermentation with Aspergillus niger could pump it out in vats. From this, the chemical industry started looking at sodium-based salts, hoping to land on something easy to control in terms of purity and cost. Monosodium citrate rose in popularity as folks realized its unique balance—it packs some of citric acid’s tartness, gives enough sodium to play a crucial role in biological processes, and does all this without drowning products in a salty aftertaste. Hospitals have relied on it since the 1940s for blood preservation, as it perks up the solution’s ability to keep blood from clotting. Now, manufacturers from China to Europe keep the supply flowing for everything from effervescent tablets to processed cheese.
Monosodium citrate anhydrous looks almost like table salt, but it tells a different story when you check the label. Known among chemists as sodium dihydrogen citrate, many call it E331(i). It keeps moisture away with its anhydrous crystal structure, which helps it store longer and dissolve faster. Most commercial packs sell this product as a white crystalline powder or fine granules, with assurance of no weird smells or off colors—a direct nod to the strict regulations in food and pharma. What sets it apart is a gentle acidity and a sodium kick that fits well in formulas aiming for taste and stability without health worries tied to excess sodium or harsh acids.
The powder’s crystal structure matters a lot for blending and solubility. Monosodium citrate anhydrous melts somewhere between 300 and 320°C without much fuss, which means factories don’t need special gear to handle it. It dissolves well in water, giving off a slight tartness, and leaves no gritty residue. It stands neutral to slightly acidic in a solution, with a pH near 3.5–4.5 in a typical 5% mix. This makes it a great buffer in both food and medical syrups, where predictable acidity supports shelf life and flavor profile. The molecule itself measures C6H7NaO7, giving it a molecular mass of 214.11 g/mol, with no water molecules hitching along compared to its monohydrate cousin.
Manufacturers stamp each batch with specs chemists can trust: purity above 99%, no heavy metals over 10 ppm, and negligible losses by drying. Quality control checks for sulfate, oxalate, and clarity, making sure nothing messes with the end-user’s expectations or health. On ingredient labels, look for names like Sodium Diacetate Monocitrate, Citric Acid Sodium Salt, or just E331(i). Regulatory authorities demand strict documentation and lot traceability, along with standardized storage advice—cool, dry spaces far from strong acids and bases. Pharmacopeias like USP or EP tell industries which test methods to follow, and that’s why reputable brands back their shipments with certificates of analysis.
Making monosodium citrate anhydrous relies on the direct reaction between citric acid and sodium carbonate or bicarbonate, followed by gentle evaporation. One batch I observed in a chemical plant took concentrated citric acid—a byproduct from massive fermenters—and neutralized it with fine sodium carbonate until reaching the right pH. After removing the leftover carbon dioxide, technicians filtered the solution and drove off water using vacuum drying instead of heating, preserving the powder’s integrity. No solvents or harsh chemicals enter the picture, which matters for manufacturers who worry about process safety and downstream purity. In large-scale facilities, engineers automate pH control and temperature to avoid batch variability, as small slips can lead to impurities that ruin the powder’s solubility or color.
Monosodium citrate doesn’t just sit in formulas; it jumps into chemical reactions, breaking down into sodium ions and citrate under mild heat or in water. Mixed with calcium or magnesium salts, it can create sparingly soluble citrates, useful for puzzles in analytical chemistry. In pharmaceutical applications, it buffers acidic drugs, tweaking their absorption profile or taste. Chemists occasionally tweak the anhydrous form, blending with other acids or basic salts to shift pH or solubility curves, opening the door for specialized uses—think slow-release tablets or medical diagnostic agents. Some manufacturers go a step further and coat the granules with food-grade polymers, extending shelf life in humid climates.
Don’t get tripped up by names—monosodium citrate wears many hats depending on region and use. E331(i), sodium hydrogen citrate, and sodium dihydrogencitrate pop up across supplier lists and pharmacopeias. Older labs might call it monosodium salt of citric acid. In food, you’ll find it grouped under sodium citrates, though E331(i) points to this specific salt. These aliases make it crucial to cross-check documentation, especially for quality audits or export paperwork.
Food safety authorities treat monosodium citrate anhydrous as a permitted additive, setting strict limits on daily intake—mostly due to sodium, not the citrate part. Workers handling pure powder in factories use gloves and dust masks; not only does fine dust irritate the nose, but cleanup becomes difficult once it cakes onto equipment. Warehouses keep it off damp floors, as moisture invites clumping and potential spoilage. Audits emphasize lot traceability, HACCP plans, and regular microbiological checks, especially when used for blood banking or medicine. Product recalls are rare, as pure batches rarely harbor microbial or chemical contamination, but rigorous supplier auditing shields manufacturers from surprises.
Monosodium citrate anhydrous pops up in some unexpected places. The food industry leans on it for processed meat and cheese, holding pH in check so flavor and color stay right. It also pops into drinks that need sugar-to-acid balance or want a sodium boost for sports recovery. Hospital pharmacies stock it to buffer oral drugs, soothe digestive upsets, and help preserve donated blood and plasma by holding calcium in check. Cleaning products use it to soften water, breaking up stubborn limescale deposits. In newer tech, biochemistry labs experiment with it during enzyme isolation—where keeping proteins happy depends on gentle, predictable buffering. The growing nutrition sector looks at it as a way to formulate less acidic sports drinks without ditching taste.
University teams and corporate research groups keep looking for ways to make monosodium citrate anhydrous cleaner, safer, and cheaper. Some projects test improved fermentation strains that spit out higher yields of citric acid—cutting the cost from the start. Others chase greener processes, aiming to recycle solvents and cut energy use during drying. In medicine, researchers are working with modified versions to act as carriers for controlled drug release. Scientists have tested using the salt in oral rehydration therapies, hoping to match the body’s own buffering systems. Research on food use targets blends with other organic acids, aiming for better control over shelf life and taste without sending sodium levels through the roof.
Most toxicology studies show monosodium citrate anhydrous ranks low for acute toxicity. Rats given big doses by mouth showed only mild digestive upset, and long-term feeding studies didn’t flag organ damage as a risk. Regulatory reviews focus on sodium intake for heart and blood pressure health, rather than citrate itself. E331(i) leaves the system unchanged, mostly peed out within a day. That said, some patients with kidney issues or severe electrolyte imbalances might want limits, because too much citrate can tip the scales in blood chemistry. Food and drug authorities in North America and Europe run regular risk assessments and have yet to find evidence of cancer, developmental, or genetic risk linked to ordinary levels of use.
Looking forward, demand for monosodium citrate anhydrous should rise with processed foods, pharma products, and smart healthcare. Food makers ask suppliers for tighter specs and certifications, reflecting consumer worries about synthetic ingredients. Cleaner production, lower energy use, and digital tracking will shape how big players compete. Research into microencapsulated forms could help extend storage life, making it useful in tropical climates or military rations. On the medical front, drug developers want citrate salts that buffer without bitter taste—especially in liquid meds for kids and seniors. In the long run, investments into biotechnology might help factories rely less on high-emission supply chains, moving closer to zero-waste citric acid fermentation. Regulatory updates will likely require better labeling, clearer hazard data, and more public reporting on supply chain ethics.
People see a name like "Monosodium Citrate Anhydrous" on a label and wonder why it’s there. Sometimes you notice it in foods, medicine, even in things you would never consider eating. The word itself sounds more at home in a chemistry textbook than in your kitchen or pharmacy, but it plays a meaningful role in everyday products.
Cooking at home often involves following recipes more than reading food science journals. I’ve mixed lemon juice into dishes for a tangy flavor. Monosodium citrate, a salt of citric acid, works almost the same way for big food companies, balancing sourness and sharpness. In sodas, jams, and canned vegetables, it tackles acidity, helping products hold their taste while sitting on the store shelf. It doesn’t mask the real flavors—more like a behind-the-scenes crew making sure the main stars don’t clash.
Rather than piling on preservatives that smack your tastebuds or go heavy-handed with artificial chemicals, food makers lean on compounds like this one to keep tastes stable. Because monosodium citrate adjusts the pH, it keeps foods from getting too sour or too bland. You’ll often spot the word “buffer” in science, which just means it stops things from going haywire. Regular folks just see it as "keeps my soup from tasting weird."
If you’ve ever sipped an electrolyte drink or picked up tablets for kidney stone troubles, you might have crossed paths with monosodium citrate and not realized it. Healthcare relies on this compound to manage acidity in the human body. I’ve seen it on ingredient lists in sports drinks in hospital wards and home pantries. Its main job? Balance acid levels in your blood or urine, which can matter a lot more than most people notice until they feel sick.
Soda loading—a term for using sodium or potassium salts to reduce uric acid or combat kidney stones—sometimes includes monosodium citrate. It’s not just for daredevil athletes or medical emergencies. Kids with mild stomach upsets, adults feeling dehydrated, elderly folks taking medications that mess with acids and salts in the body—many can benefit from small, measured doses in medical-grade products.
Walk down the supplement aisle or skim packaged food labels, and you’ll see unfamiliar names everywhere. Shoppers get nervous seeing terms they can’t pronounce. I believe folks need clear, honest information—if something like monosodium citrate keeps food safer longer, helps doctors manage a patient’s health, and gets a stamp of approval from food safety authorities, that calms nerves.
Regulations matter. The FDA keeps a close eye on food additives, and scientific committees regularly review their safety. While some buyers want pure, untouched food, current evidence supports using compounds like monosodium citrate for their intended purposes. The risks of bingeing on processed food come from too much salt, sugar, or artificial additives—not so much from compounds whose function and safety have been researched for decades.
Transparency solves half the anxiety around food chemicals. If food makers explained why they use monosodium citrate—what role it actually plays and how much ends up in the product—people might not worry so much. Also, clearer labeling in everyday language helps shoppers make their own informed choices. Doctors and dietitians who talk to families about sodium levels or acid-reducing strategies should mention these additives instead of skipping over them.
If I had to pick one thing that would help most, it’s better communication between the science world and the public. These compounds aren’t going away, so honest, practical talk about them matters in kitchens and clinics, not just labs.
Looking at the back of a soft drink or a powdered soup sachet, you might spot “Monosodium Citrate Anhydrous” in the ingredient list. A chemical-sounding name can set off alarm bells, but this one has science and experience behind its use. A salt derived from citric acid, it often acts as a flavor enhancer, preservative, or acidity regulator. Food scientists rely on it to keep tastes consistent and products shelf-stable. Whether it’s in fizzy drinks, canned vegetables, or pharmaceutical tablets, it serves a function: making processed products safer and more palatable.
Most of us want facts before deciding whether to eat something. Regulatory agencies have already looked at monosodium citrate from every angle. The U.S. Food and Drug Administration and the European Food Safety Authority both approve it as safe when consumed in typical amounts found in food. No health authority has found evidence linking normal intake to harmful effects in humans. Researchers tested the compound for various risks—acute toxicity, chronic exposure, allergic response, even for side effects in sensitive groups like children and pregnant women. No solid proof has turned up to suggest immediate or long-term hazards.
Ingredient names like monosodium citrate used to catch me off guard. After a bit of research, a few things stood out. Our bodies handle citrates pretty well—they occur naturally in fruits like lemons and oranges and play a part in the cells’ energy cycles. Drinking a lemon soda or eating canned peaches probably means taking in some monosodium salt along with the fruit’s real flavor. That said, I try to keep my diet balanced and pay attention to the bigger nutritional picture, not just single items on a label.
Most people won’t notice any effect from monosodium citrate. According to reported cases, only those with special kidney issues or rare electrolyte disorders need to watch out. This salt can affect sodium balance in the body, so anyone with kidney trouble or on a sodium-restricted diet should talk to their doctor about processed foods. No one recommends binging on processed foods, but for the general population, the amounts seen in foods are nowhere near levels that could cause harm.
Folks who want to eat fewer food additives can focus on whole foods—fruit, vegetables, and home-cooked meals. Still, having the occasional product containing monosodium citrate shouldn’t set off worry. Food manufacturers use this ingredient because it stabilizes acid and salt content, not because they want to sneak something past consumers. Clean-label trends push companies to rely less on chemicals and more on natural options. Until industry changes, reading labels and making informed choices remains the best move.
Food safety isn’t about fear—it’s about knowing what’s in your food and how much you eat. Scientific consensus supports the safety of monosodium citrate anhydrous in moderation. Real health concerns come from excess consumption of ultra-processed foods or ignoring balanced nutrition—not from individual approved ingredients. Watching intake, seeking whole foods, and listening to your body make a stronger case for well-being than obsessing over every additive. I keep an eye on labels, but I don’t let a long chemical name keep me from enjoying my lunch.
Monosodium citrate anhydrous and citric acid both show up on food labels, in pharmaceutical ingredients, and sometimes even in cleaning products. At first glance, the names sound close enough to pass for twins, but their chemistry tells a different story. Monosodium citrate anhydrous comes from neutralizing citric acid with a small amount of sodium—picture it as a salt formed between the sourness of lemon juice and a pinch of baking soda. Citric acid, on the other hand, comes straight from citrus fruits or fermentation tanks. Instead of a salt, it is a triple-acid structure. Both lend a tangy flavor and offer preservative power, but the pH, sodium content, and practical results are not the same.
In the kitchen and food industry, these two ingredients shape taste and texture in distinctive ways. Citric acid pulls the flavor towards sharp and sour, giving candies and sodas that recognizable acidic edge. Adding it too generously can make your cheeks pucker. Monosodium citrate anhydrous tastes milder. It keeps enough tartness but rounds off the sharpness, making it a go-to for balancing flavors without pushing food over the edge into true sour territory. Processed cheeses melt smooth and creamy with the help of monosodium citrate, where pure acid would break the proteins down and leave the batch stringy or grainy.
Beverage producers often swap between the two depending on their goals. If the aim is a sour soda, citric acid does the heavy lifting. Sports drinks, on the other hand, benefit from the buffers created by monosodium citrate. That small shift in chemistry helps maintain taste across long shelf lives and temperature changes. Even the amount of sodium plays a role—monosodium citrate adds extra electrolytes, which actually matters for rehydration or health-focused drinks.
Folks watching their sodium intake tend to keep an eye out for ingredients like monosodium citrate. For people managing heart or kidney issues, even the little increases from food additives can add up. Citric acid, though, barely adds any sodium but still keeps foods shelf-stable. On the flip side, not everyone tolerates citric acid easily. Some people with digestive issues notice heartburn or minor stomach problems when acidic foods stack up. That puts a spotlight on knowing the ingredients, especially for those prepping foods for kids or folks sensitive to acid reflux.
Pharmaceutical giants rely on both these substances, but for different reasons. Monosodium citrate neutralizes acids in the stomach and balances medicine pH, making some treatments gentler. Citric acid serves more for tartness and as a preservative, but less for buffering capacity. Each fulfills very particular roles—think of it like different tools in a mechanic’s kit.
Responsible manufacturers pick their additives based on science and real-life testing, not guesswork. Product developers juggle taste, pH control, health factors, and even cost before picking which to use. For home cooks, a little label reading and learning can make a lot of difference, especially when managing allergies or sensitivities. Trust in food and product labels comes from transparency—people deserve to know exactly what’s in their food.
The conversation about food and ingredient safety won’t go away. It matters because families and individuals want choices and control, especially with rising health concerns and lifestyle changes. It always comes back to understanding what we put in our bodies and making choices with facts, not guesswork. When you know the difference between two similar-sounding ingredients, you keep the power in your hands.
Monosodium citrate anhydrous, a white crystalline powder, turns up in food factories, hospitals, and chemical plants. It’s easy to brush off as “just another safe ingredient,” but safe handling at the storage stage actually matters. Lax storage can turn a routine day into a clean-up headache or, worse, a spoiled product batch. I’ve seen firsthand how corners cut here cause everything from clumpy powder to useless end products.
Dryness tops the list of storage demands. Monosodium citrate anhydrous pulls in moisture from the air. In a damp storeroom, you invite sticking, clumping, or even early breakdown. Moisture creeps in through open bags or leaky containers and clings to the crystals, ruining a batch’s flow and mixability. Sealed containers, with tight lids or resealable bags, guard the powder from humidity. Real-world tests show that exposed samples grow lumpy within days—something any production manager dreads.
Heat presents another threat. Storage rooms heated by sunlight or machines often run hotter than you’d expect. Rising temperatures can degrade the integrity of the powder and even start chemical reactions that spoil purity. Keeping stock at standard room temperature—around 25°C (77°F)—limits risks. Anyone who’s opened a storeroom door in July knows this isn’t always easy, especially in older buildings. Fans, window insulation, or relocating inventory make a difference.
Storing chemicals near strong-smelling or volatile materials invites contamination risks. I’ve watched as batches of “clean” powder come out smelling like detergent due to poor storage decisions. Use a designated area, away from cleaning supplies, solvents, and incompatible materials. Food-grade and pharmaceutical stock deserve the same strategy. Simple shelving dividers and clear labeling systems reduce mixups and the risk of accidental tainting.
A solid storage system keeps your team safe. The fine powder can irritate skin, eyes, and lungs in dusty conditions. Bags carelessly stashed at the top of overfilled shelves lead to spills nobody wants to clean, or worse, injuries. Use sturdy shelving and don’t stack too high. Pails or bins with fitted lids cut back on accidental puffs of powder in the air. Everyone who handles the product—whether it’s a food worker, janitor, or lab tech—should know that spills need immediate and proper cleanup using gloves, a mask, and a broom. Fast response reduces risk for everyone.
Routine storage checks and training ensure standards stick around. Keep an inventory sheet handy. Rotate stock so the oldest packs get used first. Watch for swelling containers, wet clumps, or changes in color. I’ve learned that overlooked storeroom corners become dumping grounds for forgotten or expired materials, so regular walkthroughs catch issues early.
Fixing storage issues starts with buying the right containers and using dehumidifiers as needed. Mark clear spots for each chemical and train new staff on these basics. If regulations require additional steps, like dedicated fireproof cabinets for chemicals, make sure those rules become standard practice. Simple, well-followed protocols drive down waste and keep both product and people out of trouble.
Monosodium citrate anhydrous plays a straightforward role in the food and beverage arena. Walk through any grocery store and you’ll find this salt behind the tang and preservation of soft drinks, jellies, and dairy products. Manufacturers turn to it for its buffering capacity, which helps keep foods at safe pH levels. Without additives like this, some products would spoil way too fast or taste off. Sour candies, ready-to-drink teas, even processed cheeses use monosodium citrate to get that right balance—not too sharp, not too bland.
Take a look at energy drinks and processed snacks—they often contain more than just sugar and flavorings. The need for consistent texture and flavor through long shelf lives has already put this compound on countless ingredient lists. Research from the European Food Safety Authority supports its use for controlling acidity in foods, which makes it a staple for food scientists aiming to meet both taste and safety standards.
Monosodium citrate anhydrous helps modern pharmacies tackle some tricky challenges. You’ll find it in oral rehydration solutions—a go-to for doctors treating dehydration caused by diarrhea or vomiting. No scientist wants children, seniors, or vulnerable groups missing out on fluids because a medicine tastes too harsh or irritates the stomach.
Hospitals stock up on products that contain monosodium citrate anhydrous, since it makes some drugs less likely to cause acid burn and palatable enough for patients to keep down. The British Pharmacopoeia and U.S. Pharmacopeia both list it as an approved pharmaceutical excipient, noting its importance in stabilizing drug formulations. Blood banks use solutions containing this ingredient to stop blood from clotting, giving nurses and doctors valuable time during transfusions and surgeries.
You may splash toners or rub lotions into your skin without thinking much about their behind-the-scenes chemistry. Yet, monosodium citrate anhydrous helps formulators stabilize pH in these products, making sure they irritate skin less and last longer in the bottle. Look through sunscreen, shampoo, and even bath bombs—this ingredient keeps them safe, stable, and pleasant to use. Cosmetic chemists won’t risk millions of dollars on products that separate on shelves or burn your skin, so small tweaks like the addition of this salt really matter.
Companies run into trouble if they ignore the balance this ingredient provides. Some people push for clean labels or seek alternatives, wanting to avoid anything synthetic. There’s room for more research into using plant-based buffers or fermenting natural alternatives, but for now, food safety agencies around the world have looked at toxicity data and found monosodium citrate anhydrous safe at permitted levels. The bigger issue is building better transparency: giving consumers clear explanations helps build trust and ensures this ingredient stays useful—and accepted—in food, drugs, and daily-use products.
| Names | |
| Preferred IUPAC name | Sodium 2-hydroxypropane-1,2,3-tricarboxylate |
| Other names |
Citric acid monosodium salt anhydrous Sodium citrate anhydrous Monosodium salt of citric acid anhydrous Citric acid sodium salt anhydrous |
| Pronunciation | /ˌmɒn.əˌsoʊ.di.əm ˈsɪ.treɪt ænˈhaɪ.drəs/ |
| Identifiers | |
| CAS Number | 18996-35-5 |
| 3D model (JSmol) | Here is the JSmol 3D model string for **Monosodium Citrate Anhydrous** (CID: 23682273): ``` data="C(C(=O)O)C(CC(=O)O)C(=O)[O-].[Na+]" ``` This is the **SMILES string** used by JSmol to render the 3D model. |
| Beilstein Reference | 17114 |
| ChEBI | CHEBI:32445 |
| ChEMBL | CHEMBL1201477 |
| ChemSpider | 54690 |
| DrugBank | DB09122 |
| ECHA InfoCard | 03b30e41-5e3a-421a-bb53-66c6dab99022 |
| EC Number | 211-529-5 |
| Gmelin Reference | 4257 |
| KEGG | C01238 |
| MeSH | D017366 |
| PubChem CID | 6224 |
| RTECS number | GE8300000 |
| UNII | ZDM23VBM9T |
| UN number | UN3077 |
| CompTox Dashboard (EPA) | urn:epa.comptox.dashboard:DB11106 |
| Properties | |
| Chemical formula | C6H7NaO7 |
| Molar mass | 214.11 g/mol |
| Appearance | White crystalline powder |
| Odor | Odorless |
| Density | 0.6 g/cm³ |
| Solubility in water | Freely soluble in water |
| log P | -2.3 |
| Acidity (pKa) | 3.13 |
| Basicity (pKb) | 6.4 |
| Magnetic susceptibility (χ) | -8.2 × 10⁻⁶ |
| Dipole moment | 2.66 D |
| Thermochemistry | |
| Std molar entropy (S⦵298) | 175.5 J·mol⁻¹·K⁻¹ |
| Std enthalpy of formation (ΔfH⦵298) | -1547.31 kJ/mol |
| Std enthalpy of combustion (ΔcH⦵298) | -1561 kJ/mol |
| Pharmacology | |
| ATC code | A09AB13 |
| Hazards | |
| Main hazards | May cause respiratory irritation. |
| GHS labelling | GHS07, GHS08 |
| Pictograms | GHS07 |
| Signal word | Warning |
| Hazard statements | Not a hazardous substance or mixture according to the Globally Harmonized System (GHS) |
| NFPA 704 (fire diamond) | 1-0-0 |
| Autoignition temperature | 210°C |
| Lethal dose or concentration | LD50 oral rat 8,400 mg/kg |
| LD50 (median dose) | LD50 (median dose): 5900 mg/kg (oral, rat) |
| NIOSH | WFJ367PC7K |
| PEL (Permissible) | Not established |
| REL (Recommended) | Up to 50 mg/kg body weight |
| Related compounds | |
| Related compounds |
Citric acid Disodium citrate Trisodium citrate Monopotassium citrate Monosodium citrate dihydrate |
