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.

Choosing a Spectrophotometer | from Cole-Parmer Blog

Spectrophotometers help us see what our human eye cannot by measuring the amount of light absorbed by a medium or object or the amount of light reflected from the medium or object. This measurement of light intensity at different wavelengths helps identify the structure or concentration of substances in a sample.

Spectrophotometry is used in many branches of science including chemistry, forensics, microbiology, physics, biology, and even in textiles. It may help identify or recognize the composition of evidence from a crime scene, or determine enzyme-catalyzed reactions, or to measure cell culture density.

Sample solutions are poured into cuvettes, which are inserted into the spectrophotometer to be read. The cuvette should be tested for performance by running it in the spectrophotometer several times. Inconsistencies in values may indicate poor molding or poor fit. Also the spectrophotometer should be calibrated before use for accurate readings.

Variables to Consider When Choosing a Spectrophotometer

Wavelength range
Detection limits
Density, shape, or size of the product you wish to measure
Analytical working range
Sample throughput (single sample vs. multi-sample)
Data quality
Cost of instrument and associated consumables
Customizable and/or pre-configured method options
Measurement time
Footprint of instrument

Types of spectrophotometers include Visible Light Spectrophotometers, UV/Visible Spectrophotometers, Near-Infrared (IR or NIR) Spectrophotometer, NMR, Atomic Absorption Spectrophotometer, Mercury Spectrophotometer or Analyzer, and Fluorometers.

Users can obtain quick and accurate measurements in the field with specialty spectrophotometers (such as the mercury analyzer). These units are often used for environmental testing, especially in assessing drinking, surface, saline, and waste waters. They are effective when surveying water quality and monitoring hazardous wastewater.

Choosing a Spectrophotometer

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