What is the difference between an analytical balance and a precision balance?

An analytical balance provides readability of 0.1 mg or better, while a precision balance typically reads to 0.001 g or 0.01 g. Analytical balances include draft shields and are designed for highly sensitive measurements. Precision balances handle larger samples and are less affected by environmental conditions.

What readability do I need for my lab application?

You need a readability that is at least one-tenth of your smallest sample weight or required measurement increment. For example, measuring 100 mg samples may require 0.01 mg readability, while gram-level work may only need 0.01 g. Selecting higher readability than necessary increases cost without improving results.

Do lab balances need to be calibrated?

Yes, all lab balances require regular calibration to maintain accuracy. Calibration ensures measurements remain traceable to certified standards. Internal calibration simplifies this process by automating adjustments, while external calibration requires manual verification with certified weights. In regulated environments, calibration records must be documented and retained.

What is the difference between readability and repeatability?

Readability is the smallest increment of weight a balance will display. Repeatability is the degree of agreement between multiple measurements of the same mass, on the same balance, under the same conditions.

What is the best way to clean my balance to ensure accurate readings?

Inspect and clean before each use. A flannel cloth or soft brush works well for dusting and light cleaning. Use a non-abrasive cleaner for light spills, and a dry flannel cloth for glass parts. Set a regular maintenance schedule for deep cleaning to ensure optimal performance and instrument longevity.

Can vibration affect the accuracy of my balance?

Yes — even slight vibration from a heavy footstep can affect accuracy. Place the balance on a sturdy benchtop away from high-traffic areas such as hallways, elevators, stairways, and doors. If that placement is not possible, an anti-vibration table should be considered.

Conductivity and Conductivity Meters

Conductivity is the measurement of the electrolytes in a solution and is defined as the conductance in a given volume. Conductance is the ability of the solution to conduct electric current.

Oakton® Instruments CON 11 Handheld Conductivity/TDS Meter

Here are some typical questions about conductivity:

Q: How does temperature affect conductivity readings?

A: The effect depends on the solution to be measured. The effect is greatest in low ionic strength (low conductivity) solutions. A general rule to follow is there will be a 2% change (increase)/degree C. This rule can be followed for most aqueous solutions, however if you require a high degree of accuracy, you should consult a chart for the particular solution you are measuring. Organics also have very different temperature curves.

Q: What is the difference between conductivity and salinity?

A: The probe is the same for conductivity and salinity, but a correction factor is applied to the reading in a salinity meter. The correction factor takes the conductivity reading and converts it to ppm of a specific salt. The salt varies from manufacturer to manufacturer. Some use NaCl while others use CaCO₃.

Q: How are conductivity and TDS related?

A: Salts, minerals, and even dissolved gases contribute uniformly to the conductivity of a solution. This means that the conductivity can be used as an indicator of the amount of dissolved materials in a solution. TDS can be used fairly accurately when comparing the status of a single source, such as NaCl, but error can arise when trying to compare two different types of solutions. It is necessary to calibrate the meter using the same dissolved materials that are in the test solution.

Q: Are conductivity probes interchangeable with meters?

A: No, you cannot place one manufacturer’s probe on another manufacturer’s meter. The cell constant may be different and the pin configurations are usually different. The type of thermistor used for temperature compensation is usually different also. The cell constant is not a big problem, but not matching the pin configuration and temperature compensating element used would be a problem.

See all conductivity meters.

Conductivity and Conductivity Meters

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