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When it comes to working with chemicals and reagents in the lab, it’s important to be aware of the different grades that are available.
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What to Consider When Purchasing Different Grades of Chemicals

Not all chemicals and reagents are created equal, and knowing which grade is right for your needs can make a big difference in terms of quality, safety, and cost

Aimee O’Driscoll

When it comes to working with chemicals and reagents in the lab, it’s important to be aware of the different grades that are available. Not all chemicals and reagents are created equal, and knowing which grade is right for your needs can make a big difference in terms of quality, safety, and cost.

What lab managers should know about the main chemical grades available

The most common grades of chemicals and reagents are ACS, reagent, USP, NF, laboratory, purified, and technical. The main difference between the various grades is purity, with ACS grade chemicals having the highest purity (95 percent or above) and technical grade the lowest. These grades can be more generally categorized in the following ways:

Food and drug grades: ACS, USP, and NF grades meet or exceed standards set by the American Chemical Society (ACS), United States Pharmacopeia (USP), and National Formulary (NF), respectively. These three grades, along with reagent grade chemicals, are of the highest purity and are typically interchangeable. They are usually acceptable for use in food, drugs, and medicine, and as such, are subject to strict quality control measures. This means they are usually more expensive than other grades, but they’re also more reliable.

Educational grades: Laboratory grade chemicals are generally of high purity, but they are not subject to stringent standards and their exact purity is unknown. These chemicals and reagents are ideal for use in educational settings. Purified grade chemicals don’t meet an official standard but could still be used for educational purposes and other general applications.

Industrial or technical grade: Technical grade chemicals are the lowest quality products available. They’re designed for general use in a variety of applications, and as such, they’re not subject to the same quality control measures as other grades. Technical grade chemicals are inexpensive and are often used in industrial and commercial settings, although not where food or pharmaceuticals are involved.

While the grading systems help, lab managers still need to take a close look at each product’s specifications before determining its suitability for use.

For the best quality of data, high quality solvents and reagents are a requirement.

Why is choosing the right grade so important?

Choosing the right grade of chemical or reagent is vital for several reasons. One is that using a low-purity grade can lead to low-quality results, with the impact depending on your application and how sensitive your requirements are. Chelsea Plummer, PhD, senior product marketing manager, chemistry at Waters Corporation, notes that in LC and especially in LC-MS methods, even small amounts of contamination can decrease sensitivity, leading to incorrect detection limits. “For the best quality of data, high quality solvents and reagents are a requirement.”

As Plummer explains, “there are two main repercussions and complaints that often stem from choosing the wrong grade of chemical or reagent.” First, you could end up with confusing results—for example, a complex MS spectrum—which makes data analysis extremely challenging. You might also find yourself taking additional time to troubleshoot, or worse, adding downtime to clean your system from the contamination that can be left over when using the wrong grade of solvents and chemicals.

Choosing too low a grade can result in noncompliance and safety concerns, particularly in any environment involving food or pharmaceuticals. It can also lead to higher costs due to having to repeat processes or deal with expenses related to equipment damage or replacement. Conversely, using a higher-purity grade than required will lead to higher costs than necessary.

How to choose chemicals and reagents for your applications

When purchasing chemicals and reagents, it’s important to consider the intended application, balance cost with required purity, and look to regulatory requirements for guidance. Even if you’re not restricted by industry standards, you may decide that other factors warrant the use of high-purity reagents. As Plummer notes, due to the high cost of some lab instruments such as LC-MS systems, getting the most out of the accuracy and sensitivity of these systems should be a priority by using the right solvents and reagents.

Aside from choosing the right grade, you should also look at the intended use for that particular chemical or reagent. For example, in the case of LC-MS, Plummer says using MS-labeled solvents is recommended as HPLC grade will not be pure enough It’s also worth noting that simply checking the label of products is not enough, and you should also consult documentation such as MSDS sheets and certificates of analysis  to confirm a product’s suitability for your application.

Choosing too low a grade can result in noncompliance and safety concerns, particularly in any environment involving food or pharmaceuticals.

Another area to consider is benchmarks. If you’re comparing samples to standards, you need to ensure that your chemicals and reagents are of the same grade as those used to produce your benchmark samples, and vice versa. Of course, price is also a consideration when purchasing chemicals and reagents. High-purity products are usually the most expensive and technical grade chemicals are the cheapest. However, it’s important to remember that you get what you pay for and choosing the wrong grade can lead to higher long-term costs.

When it comes to choosing chemicals and reagents, there’s no one-size-fits-all solution. It’s crucial to consider the intended use, the grade of the product, and the price before making a purchase. With these factors in mind, you can be sure to select the best chemicals and reagents for your needs.