Questions & Answers I EM Grade

Water is essential to life science research, but for many scientists, the most important reflection on this most widely used laboratory reagent is “how much do I need?” Because water is capable of acting as a solvent for many substances and reagents (aqueous solution), beware it can become contaminated. Water can also be a dilution medium.

Link to Boyang

Even within the same laboratory, the water used in one experiment may differ from that used in another. There are a multitude of methods, devices and means of producing purified water, so we’ll need to specify the means of producing this water. Not all water is the same, so consider water as a laboratory reagent and examine it accordingly. Understanding the importance of water quality and monitoring it closely is important to ensure experimental reproducibility over several days, months and even years.

The American Chemical Society (ACS), with over 150,000 members, is one of the world’s largest scientific organizations and one of the world’s leading sources of authoritative scientific information on chemistry.

It publishes references, orders and describes every ACS product according to a standardized method. If you need more detailed information about a chemical product with an ACS label, you can find its exact composition in the database available free of charge on the https://www.acs.org/content/acs/en.html website.

Microfiltered solutions are produced by vacuum filtration on a membrane (filtration device). There are many different types of membrane (diameter, porosity, materials, etc.)

Membranes used to filter an aqueous solution are made from a cellulose-based filter (cellulose ester), with a diameter adapted to your filtration device and a porosity of 0.4µ or 0.2µ (the 0.2µ porosity also enables bacteria to be retained (hence the sterilization method).

All products on the market generally have an expiration date. This doesn’t necessarily mean you can’t use them after that date. The expiration date is the date on which the supplier’s warranty on your product expires.

We’ve all tested this, sometimes using chemicals that have been out of date for several years, and the result was excellent (it generated less waste). It’s important to remember that product shelf-life is highly dependent on packaging and storage.

EM-grade aims to be an eco-responsible player in the electron microscopy sector, promoting the rational use of chemicals which have a dual impact on our environment and our health.

If we can’t do without certain sometimes toxic products, then let’s consume better and less often.

That’s why we prefer to sell products in small volumes and small packaging sizes, to avoid stocking up for years on end in laboratory waste.

A neutral (inert) gas is a stable gas (meaning it already has 8 valence electrons in its outer shell and doesn’t need to react to reach these 8 electrons). These gases are also known as noble or rare gases. They do not initiate chemical reactions on their own (nitrogen is an inert gas, as is Argon, the most widely used in EM-grade conditions).

When the buffer has a high concentration, from 0.4 molar upwards, it can crystallize to some extent when stored in the refrigerator. This condition is reversible, as the crystals will dissolve within a few hours at room temperature. You can reheat it to accelerate the disappearance of the crystals. This crystallization does not change the chemical properties of the buffer.

DPBS (Dulbecco’s Phosphate Buffered Saline)

PBS (Phosphate Buffer Saline). Due to osmolarity constraints associated with the fixative, or for rinsing purposes, it is generally prepared at 0.1M or 0.2M at a pH of around 7 to 7.4, to compensate for the slight acidity released by cells during fixation.

DPBS (developed by Dulbecco) may contain CaCl2 and MgCl2 additives to facilitate cell detachment in culture. If DPBS does not contain these additives, it can be replaced by PBS.

It is not a vital buffer, as it contains traces of toxic elements such as arsenic.

However, it is still widely used when fixing cells (since fixing kills the cell). In this case, cacodylate’s toxicity is no longer a drawback. On the contrary, its toxicity becomes an advantage, thanks to its ease of preparation. It has a long shelf-life (toxic to micro-organisms) and does not require sterilization.

The usefulness of imidazole-buffered osmium tetroxide as a lipid preservative in transmission electron microscopy is highly recommended, as imidazole allows lipid retention and maintenance even after alcoholic dehydration. As an example, Rat liver and other tissues were perfusion-fixed with glutaraldehyde and post-fixed with osmium-imidazole, and the appearance of lipid droplets was compared to that after fixation in aqueous osmium tetroxide unbuffered with imidazole. Prominent electron-opaque staining of lipid droplets and lipoprotein particles was noted after post-fixation with 1% 0.1M osmium-imidazole, pH 7.5, for 30 min. (more details see protocol).

Better manage your chemical inventories with a simple quantified inventory to anticipate your purchases.

For more Electronic Grade Chemicalsinformation, please contact us. We will provide professional answers.

Group your purchases together to save money, but above all to limit the carbon impact on the planet.

We often negotiate delivery costs without considering the impact on our environment.

EM-grade will give you a discount on delivery costs for all grouped orders.

For small volumes, seal in an ampoule or Airless bottle.

For larger volumes, we inject argon or nitrogen, saturating the liquid by bubbling the bottled solution to replace the oxygen or carbon dioxide contained in the water.

But when you open the bottle, you lose the neutral atmosphere. That’s why we sell small volumes to avoid waste.

There’s no risk of running out of your products for your experiments, as they’re produced on the day you order them and dispatched immediately.

Mixtures containing Paraformaldehyde (PFA) and glutaraldehyde

The combination of Paraformaldehyde with glutaraldehyde as a fixative for electron microscopy benefits from the rapid penetration of small HCHO molecules, which initiate stabilization of the tissue structure. Rapid and complete cross-linking is caused by the more slowly penetrating glutaraldehyde oligomers. This mixture is associated with the name Morris J. Karnovsky of Boston. It is an example of a great innovation that was published only in an unrefereed abstract (Karnovsky, ).

His original mixture contained 4% glutaraldehyde, which was a higher concentration than many people wanted to use (Hayat, ). Designations like “half-strength Karnovsky” became common parlance in the s and s. Primary fixative helped to resolve observations of tissues that were difficult to preserve em Electron microscopy . the introduction of Karnovsky fixative, and they are still commonly used.

Aldehydes are the most commonly used fixatives. They are used to stabilize the fine structural details of cells and tissues prior to light or electron microscopy.

Like glutaraldehyde , paraformaldehyde is also commonly used and will depolymerize into formalin when heated, making it an effective fixative too.

Why is glutaraldehyde used in electron microscopy? 

Glutaraldehyde is one of the most frequently used fixatives. It reacts rapidly with proteins and, as a dialdehyde, stabilizes structures by cross-linking before there is any possibility of buffer extraction. 

To avoid denaturing glutaraldehyde, it should be stored at 4°C. 

About Semiconductor/Electronic grade chemicals

Semiconductor grade and electronic grade chemicals are specifically intended for use in the electronics industry, including manufacture and maintenance of electronics. These types of reagents must comply with strict quality standards. The presence of particles and metal ions must be kept extremely low since these impurities would interfere with the performance of electronic products.

Semiconductors are materials that have partial conductivity, somewhere between conductors and nonconductors (aka insulators). Semiconductors are essential to the manufacture and proper functioning of electronic apparatus such as televisions, computers, and medical devices.

High-quality semiconductor and electronic grade chemicals are essential across the electronic industry. For example, these types of reagents are required for the manufacture of circuit boards, display panels, solar cells, conductive polymers, electrical coatings, battery materials, and much more. The electronics industry plays an irreplaceable role in almost all other industries, as well as in our day-to-day lives.

Lab Alley supplies high-purity, electronic grade and semiconductor grade chemicals you can trust for optimal performance in the electronic applications.

Major uses and applications

The following areas are the most prevalent applications for semiconductor and electronic grade chemicals.

Contact us to discuss your requirements of High Purity Solvents. Our experienced sales team can help you identify the options that best suit your needs.

• Cleaning and maintenance of electronics: Electronic grade solvents are required for cleaning and degreasing of electronic equipment and parts, such as chips and circuit boards.
• Manufacture: Electronic and semiconductor grade chemicals are used as raw materials in the manufacture of semiconductors and electronics.

Common Uses and Applications

• Circuit boards
• Display panels
• Semiconductors
• Solar cells
• Conductive polymers
• Electrical coatings
• Battery materials
• Capacitors
• Cleaning of electronic equipment
• Electronic packaging

Industries