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abstracts, articles, and osmolality basics. A handy glossary is included for quick reference on key terms related to our core testing services.
The Basics of Osmolality
The concentration of a solution expressed as the total number of solute particles (osmoles) per kilogram of solvent. When solutes are added to a pure solvent the resulting solution differs from the pure solvent in several ways including freezing point, boiling point, vapor pressure, and osmotic pressure.
The change in these characteristics is not proportional to weight, size or shape of the added solutes, resulting in the importance of osmolality in determining the concentration of solutes.
Osmolality is the number of Osmols of solute particles per kilogram of the pure solvent. As most ionic species do not completely dissociate, osmolality is a unit of concentration, which takes into account the dissociative effect. Osmolality is usually expressed in mOsm/kg H20. One milliosmol (mOsm) is 10-3 osmols. The osmolality equation is:
Osmolality = ΦnC = osmol / kg H20
Φ = osmotic coefficient, which accounts for the degree of molecular dissociation
n = number of particles into which a particle can dissociate
C = molal concentration of the solution
Bromate is an anion of the structure of BrO3_ it is often in the form of a sodium or phosphate salt. Bromate is produced during the process of cleaning and disinfecting water. Bromate is a suspected carcinogen, and as such, the concentration of bromate in municipal, well, and bottled water is regulated by the Environmental Protection Agency (EPA) and other regulatory bodies throughout the world. Due to the chemical nature of purified water, bromate content may increase over the lifetime of water-based products and The Osmolality Lab recommends monitoring bromate over the shelf life or holding tank life of these products.
Chlorate is a chemical anion that may enter your drinking water from several potential sources, including from hypochlorite or chlorine dioxide disinfection and source water contamination from pesticide runoff or papermill discharges. The Chlorate ion is also known byproduct of the drinking water disinfection process, forming when sodium hypochlorite or chlorine dioxide are used in the disinfection process. Due to the chemical nature of purified water, chlorate content may increase over the lifetime of water-based products and The Osmolality Lab recommends monitoring chlorate over the shelf life or holding tank life of these products.
Conductivity is a measure of a material’s ability to conduct an electric current, which provides a measure of what is dissolved in the water or solution, important measurements of water and/or solution quality. Conductivity may be an important measure of product or solution stability over time and should be evaluated for inclusion in product stability protocols.
Free chlorine refers to both hypochlorous acid (HOCl) and the hypochlorite (OCl-) ion or bleach and is commonly added to water systems for disinfection. When ammonia or organic nitrogen is also present, chloramines known as monochloramine, dichloramine, and trichloramine will quickly form. Chloramines are also known as combined chlorine. The presence of free chlorine (also known as chlorine residual, free chlorine residual, residual chlorine) in drinking water indicates that: 1) a sufficient amount of chlorine was added initially to the water to inactivate the bacteria and some viruses that cause diarrheal disease; and, 2) the water is protected from recontamination during storage. The presence of free chlorine in drinking water is correlated with the absence of most disease-causing organisms, and thus is a measure of the potability of water.
Total Chlorine Test
Total chlorine is the sum of free chlorine and combined chlorine. Using chlorine is one method water treatment facilities keep water free of bacteria and harmful organisms. The presence of chlorine residual in drinking water indicates that: 1) a sufficient amount of chlorine was added initially to the water to inactivate the bacteria and some viruses that cause diarrheal disease; and the water is protected from recontamination during storage.
Microbiology testing services are a crucial requirement across many industries worldwide where products, processes and human health are at risk of being negatively affected by the presence and breeding of micro-organisms such as specific pathogens, bacteria, yeast and molds.
Organoleptic properties are the aspects of food, water or other substances that an individual experiences via the senses—including taste, sight, smell, and touch. Organoleptic tests are conducted to determine if food or pharmaceutical products can transfer tastes or odors to the materials and components they are packaged in. Shelf life studies often use taste, sight, and smell to determine stability of the product.
Osmolality by Vapor Pressure
Vapor pressure measurement is a reliable method of determining osmolality. Vapor pressure osmometry is superior for many fluids in biology and medicine in which water is the solvent. The vapor pressure method determines osmolality at room temperature with the sample in natural equilibrium. This precludes cryoscopic artifacts due to high viscosity, suspended particles, or other conditions that can interfere with freezing point determinations, giving vapor pressure osmolality tests a broad range of error-free applications. Osmolality is a stability indicating analysis and is recommended to be included in stability testing protocols for applicable products by The Osmolality Lab.
Osmolality by Freezing Point
Freezing Point Osmometry determines the osmotic strength of a solution by utilizing freezing point depression. Osmolality by freezing point test is an important diagnostic method used in a broad range of applications not currently available by any other means to measure the total number of particles in a solution. Freezing point osmometers are the industry-preferred solution in chemistry, pharmaceutical and quality control labs. Osmolality is a stability indicating analysis and is recommended to be included in stability testing protocols for applicable products by The Osmolality Lab.
Acidity and alkalinity are measured with a logarithmic scale called pH. The pH scale ranges from 0 to 14. A pH of 7 is considered neutral. A pH less than 7 is acidic. A pH greater than 7 is basic (or alkaline). pH is used to monitor the quality and reproducibility of a product along with safety and stability.
Salinity is the measure of all the salts dissolved in water. Salinity is usually measured in parts per thousand (ppt). The average ocean salinity is 35ppt and the average river water salinity is 0.5ppt or less. This means that in every kilogram (1000 grams) of seawater, 35 grams are salt.
Total Dissolved Solids refers to any minerals, salts, metals, cations or anions dissolved in water. Total dissolved solids (TDS) are comprised of inorganic salts (principally calcium, magnesium, potassium, sodium, bicarbonates, chlorides, and sulfates) and some small amounts of organic matter that are dissolved in water.
Viscosity is a principal parameter when any flow measurements of fluids, such as liquids, gels, creams and lotions are made. Gathering viscosity data on a material gives manufacturers the ability to predict how the material will behave in the real world. For example, if moisturizing cream does not have the correct viscosity, it can either be too difficult to squeeze out from the tube or dispense too much all at once. Knowing the viscosity of a material also affects how the production and transportation processes are designed. Viscosity measurements are often the, most accurate and most reliable way to analyze some of the most important factors affecting product performance. As the viscosity of a solution, gel or lotion is dependent on the chemical composition, viscosity is a stability indicating analysis and is highly recommended as inclusion in stability monitoring.
Literature, Abstracts and News
• “Electrolytes: Definition, Functions, Imbalance and Sources”
• “Fluid and Electrolyte Balance”
• “The Effects of Sports Drink Osmolality on Fluid Intake and Immunoendocrine Responses to Cycling in Hot Conditions”
• “Osmolality of Frequently Consumed Beverages”
• “Scientific opinion on the substantiation of health claims”
• “Mucosal irritation potential of personal lubricants relates to product osmolality…”
• “Use and procurement of additional lubricants for male and female condoms: WHO/UNFPA/FHI360”
• “Vaginal hygiene products like sprays, wipes, creams linked to infections: study”
• “Osmolality and pH Properties of Some Commercial Lubricants”
• “Global Consultation on Personal Lubricants”
• “FDA warns manufacturers of products labeled as homeopathic for putting consumers at risk with significant violations of manufacturing quality standards…” https://www.fda.gov/news-events/press-announcements/fda-warns-manufacturers-products-labeled-homeopathic-putting-consumers-risk-significant-violations
• “Statement from FDA: transformative new steps to modernize FDA’s 510(k) program…” https://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm626572.htm
• “Beverage Osmolality as a marker for maintaining appropriate body hydration”
Osmolality (Vapor Pressure)
Freezing Point Test