Everyone from a science student to an internationally known researcher needs an accurate and dependable analytical balance. Engineers keep advancing the fundamental weighing technology. As Tom Delano, vice president of business development at Adam Equipment in Danbury, CT, says, “There are always some small changes or advances in the way things are weighed, the weighing mechanisms.”
Beyond the changes inside balances themselves, the external market drives the evolution of this technology. Ian Ciesniewski, technical director at Mettler Toledo in Columbus, OH, describes two key market trends. “One is customers pushing for smaller and smaller errors and smaller limits on the sample size,” he says. “This is driven by pharmaceutical and biotechnology companies.” Ciesniewski says that economics explains the second driver. “Customers need to control costs and increase productivity,” he says. “Part of that falls on the balances.”
Users expect better interfaces. In fact, Delano calls this the “big area of change.” He adds, “Today’s balances can include very sophisticated software and even touch-screen displays.”
Some of the electronic advances might go unnoticed but not unappreciated. As Jennifer Camarda, sales specialist for premium weighing at Sartorius Lab Products & Services, headquartered in Goettingen, Germany, says, “Having a leveled balance is critical for proper weighing results, as even the slightest incline can cause inaccurate results.” She adds, “At the push of a button, the Cubis Q-Level will automatically level within seconds to ensure accurate weighing.”
Users also seek other forms of lab efficiency from an analytical balance. “There’s an ever-increasing move toward automation on the data-handling side,” says Ciesniewski. “This includes a critical need to control calibration processes.”
Consequently, many users look for an analytical balance with onboard, durable storage and communication ability, or both. “In many applications,” says Ciesniewski, “you can’t just have a user creating weigh data, as this creates traceability issues.”
Keeping weights consistent
To ensure that an analytical balance provides a reliable, accurate output, it must be adequately serviced. Ciesniewski says that this requires service by a manufacturer-certified vendor twice a year. When asked what features of an analytical balance matter most, Guy Grundwell, professor of chemistry and biochemistry at Central Connecticut State University in New Britain says, “Durability and accuracy.”
Overall, the accuracy of a balance’s output depends critically on the operation and the surroundings. For one thing, Ciesniewski says, “Choose a balance with an estimated error that is never more than one-third of the expected tolerance for the weighing task. This ensures that the balance’s measurement uncertainty—error—remains relatively insignificant.” He adds, “The degree of error in an average weighing is much smaller than it was twenty or twenty-five years ago, and most of the uncertainty is external to the balance.” Understanding and controlling the external conditions— including the environment and user or sample-related variables—will help minimize weighing errors.
The environment can create problems that few users consider. As Camarda says, “Static is one of the most common issues that affect weighing measurements, especially during cold months when humidity is low. To minimize the effects from electrostatic charges, Sartorius designed Cubis Q-Stat, an analytical draft shield within the Cubis portfolio that contains an integrated 4-jet ionizer without disruptive air streams to quickly dissipate electrostatic charges built up on sample vessels and substances directly inside the weighing chamber.”
Controlling an analytical balance’s environment and use produces more accurate results.
For additional resources on analytical balances, including useful articles and a list of manufacturers, visit www.labmanager.com/balances