Lab Manager Magazine's Independent Guide to Purchasing a Lab Balance

Choosing the right balance comes down to three main selection criteria outlined in the Independent Guide to Purchasing a Lab Balance.

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Choosing the correct balance for your application, or a series of balances that suit all of your application needs, is the first step in good lab weighing practices. If you choose the correct balance, calibrate it regularly, including any time the balance is moved to a new location, and keep it clean, your balance will reward you with many years of accurate operation. Choosing the right balance comes down to three main selection criteria outlined in the Independent Guide to Purchasing a Lab Balance. Once you've read this guide, head over to LabWrench.com to check out the latest lab balance models.

Where to Start

First, you should consider the readability of the balance. This represents the smallest change in weight the balance will detect. Next, make sure you choose the balance that matches the weight of what you will be weighing. Finally, take a look at one of the most expensive features you can have on your balance—automatic internal calibration—and decide if it’s worthwhile for this balance purchase. If you cannot find one single balance that meets all of your weighing needs, you are not alone; most lab work benches require a combination of many of the balances described below. The flexibility and customization of your weighing stations will more than make up for the initial up-front costs.

Analytical Balances

Analytical Balances are those with readability typically between 0.01 mg (0.00001 g) and 1 mg (0.001 g). Applications for an analytical balance in the lab include: differential weighing, interval weighing when connected to a PC with special software, formulation weighing, density measurement, pipette calibration, sample management and any other analytical weighing needs your lab has. Analytical lab balances offer the second widest range of weighing capacities usually around 500 g. Choose from one of the two ranges below before deciding whether automatic internal or manual calibration is best for your lab.

A. With a weighing capacity range of 1 to 250 g, this first group of analytical balances will fit your needs for small analytical measurements. Analytical balances are some of the most common types in the lab, so you should find a large selection to choose from. From here, you will decide whether you would like a balance with automatic internal calibration or manual calibration.

B. With a weighing capacity range of 250 to 500 g, the second group of analytical balances will fit your needs for analytical measurements on the larger end of the spectrum. Analytical balances are some of the most common types in the lab, so you should find a large selection to choose from. From here, you will decide whether you would like a balance with automatic internal calibration or manual calibration.

  • Automatic Internal Calibration is likely the most costly feature on your balance, aside from the readability and capacity. However, it is very convenient and can save valuable time. Many balances with this feature also come with external calibration.
  • Manual Calibration is the traditional method of placing a certified calibration weight on the balance and entering the calibration mode of the balance. Only the external weight would need to be sent away for re-certification to ensure your balance is calibrated correctly.

Precision Balances

Precision Balances are those with a readability typically between 1 mg (0.001 g) and 1 g. Applications for a precision balance in the lab include: GMP, ISO and other quality management systems, weighing, dynamic weighing, interval weighing when connected to a PC with special software, formulation weighing, sample management and any other daily precision weighing needs you have in your lab. Precision lab balances offer the widest range of weighing capacities with maximum capacities usually around 70,000 g. Choose from one of the two ranges below before deciding whether automatic internal or manual calibration is best for your lab.

A. The weighing capacity range of 1 to 35,000 g is found in this first group of precision lab balances to choose from. Most manufacturers offer a precision balance in this range. From here, you will decide whether you would like a balance with automatic internal calibration or manual calibration.

B. The weighing capacity range of 35,000 to 70,000 g is found in this second group of precision lab balances. Most manufacturers offer a precision balance in this range. From here, you will decide whether you would like a balance with automatic internal calibration or manual calibration.

  • Automatic Internal Calibration is likely the most costly feature on your balance, aside from the readability and capacity. However, it is very convenient and can save valuable time. Many balances with this feature also come with external calibration.
     
  • Manual Calibration is the traditional method of placing a certified calibration weight on the balance and entering the calibration mode of the balance. Only the external weight would need to be sent away for re-certification to ensure your balance is calibrated correctly.

Microbalances

Microbalances are those with a readability typically between 1µg (0.000001 g) and 0.01 mg (0.00001 g). Applications for a microbalance include: stent weighing, particulate matter weighing, pipette calibration, elemental analysis of glass, analysis of pesticides and any other critical microweighing applications in your laboratory. Lab microbalances usually have a maximum capacity of approximately 50 g. Choose from one of the two ranges before deciding on calibration options.

A. A smaller weighing capacity range of 0 to 25 g represents the first grouping of microbalances. This small weight is required in order to obtain the high resolution a microbalance provides your lab. The selection of manufacturers to choose from is limited as only a few can produce such an outstandingly accurate balance. From here, you will decide whether you would like a balance with automatic internal calibration or manual calibration.

B. A slightly larger weighing capacity range of 25 to 50 g represents this second grouping of microbalances. This small weight is required in order to obtain the high resolution a microbalance provides your lab. The selection of manufacturers to choose from is limited as only a few can produce such an outstandingly accurate balance. From here, you will decide whether you would like a balance with automatic internal calibration or manual calibration.

  • Automatic Internal Calibration is likely the most costly feature on your balance, aside from the readability and capacity. However, it is very convenient and can save valuable time. Many balances with this feature also come with external calibration.
     
  • Manual Calibration is the traditional method of placing a certified calibration weight on the balance and entering the calibration mode of the balance. Only the external weight would need to be sent away for re-certification to ensure your balance is calibrated correctly.

Ultra-Microbalances

Ultra-Microbalances are those with a readability of 0.1µg (0.0000001 g). Applications for an ultra-microbalance include: particulate matter weighing, ashing or incineration, drying, measurement of coatings, checking spillage quantities and any other application that would require the most accurate measurement possible. Lab ultra-microbalances usually have a maximum capacity of approximately 5 g.

Lab Balance Sponsors:

METTLER TOLEDO is a leading global manufacturer of precision instruments with a broad offering which includes analytical and precision balances, moisture analyzers, titrators, electrochemistry, density and refractometry, thermal analysis systems, and service. Our expansive analytical balance offering ranges from the simple NewClassic balance, for basic weighing needs, up to our Excellence (XP/XS) Solution offerings. METTLER TOLEDO analytical balances have been designed for the utmost in efficiency and ease-of-use in mind. For our Excellence line of balances, the SmartGrid weigh pan’s unique appearance and innovation are raved about by customers. Weighing results are faster and more stable as any air currents in the draft chamber pass freely through the weigh pan. In the past, any spilt sample was a hassle with the necessity to clean the weigh pan to achieve an accurate result. Now, any substance falls harmlessly through the SmartGrid and into the catch tray without affecting the weighing result. Ergoclips fasten directly to the SmartGrid, and allow you to confidently secure any tare container for more efficient weighing. Additional features of the balance include a color touchscreen, SmartSens for hands free operation, and optional ionizer integration to diminish any static issues. 1-800-METTLER | www.mt.com

It’s All About The Perfect Balance… For nearly forty years, customers and professionals alike have trusted the Adam brand for speed, performance and value. Today, more than ever, customers turn to Adam for their balance and scale needs. Internationally recognized for reliability and backed by responsive support and sales, Adam serves the laboratory, education, industrial, retail, and medical markets globally with a large selection of balances and scales ranging from simple compact portable scales to precision top loading analytical balances and moisture analyzers. Packed with features scientists need and performance they demand, Adam offers the best value for their customers. Learn more at www.adamequipment.com.

RADWAG is the biggest manufacturer of electronic weighing instruments in Poland and one of the leading producers in Europe. Radwag has introduced system of quality control ISO 9001:2000 confirmed by TÜV certificate. Radwag manufactures wide range of modern electronic balances: microbalances (from 0.1 μg), analytical balances (from 0.01 mg), precision laboratory balances, moisture analyzers, mass comparators. RADWAG produces also industrial and medical scales, checkweighers, measuring indicators and multi-stand weighing systems. All of Radwag products are manufactured in its own factory in Europe. Radwag has 9 trade offices in Poland and sales network in over 60 countries all over the world. http://scales-balances.net/en/index.html.

Categories: Purchasing Guides

Published In

Rethinking Green Magazine Issue Cover
Rethinking Green

Published: April 1, 2010

Cover Story

Rethinking Green

While the green movement is receiving less attention now than it has in recent years, it was able to take root with regulators who have become less tolerant of practices found to harm the environment. Many lab managers believe that adjusting their processes now may be more economically efficient and less disruptive to their work than racing to meet regulatory deadlines in the future.