Lab Scale

Tablet splitting is a common practice when you need to give less than a full dose. However this has significant risks as this study found out.  Five volunteers were asked to mimic the practice in nursing homes using a splitting device, a scissor, and a kitchen knife.  The splitting device turned out to be the most accurate way to split a tablet.  Using an analytical balance the researchers measured the difference between each of the methods before and after the split.  The scissor and knife produced statistically similar results while the splitting device had a statistically significant lower mean deviation from the theoretical weight after the split.  There was also significantly less weight loss with the device than with the knife or scissors.

For further information visit www.ncbi.nlm.nih.gov.… Read the rest

This study examines the effect of electrochemical corrosion on waste packages where there is a significant possibility of exposure to humidity leading to water film formation and subsequently corrosion.  The objective of the study was to test the susceptibility of different metals under different ranges of humidity over a long term period of 5 years or more.  The results of the study would then form the basis of input to other programs including things like ‘Recommendation for Container Materials’ amongst others.  An analytical balance and a calipers were used to measure and weigh the test specimens.  Both were calibrated with NIST traceable gage blocks and weights.

For further information visit e-reports-ext.llnl.gov.… Read the rest

Here is the essential details of day 1 in a course in instrumental chemical analysis.  The objective of the course is to give students experience in using the instruments used in Analytical Chemistry.  The course stresses on both the instruments as well as the methods used to perform analysis.  The typical lab will have optical spectrometers, chromatographic equipment, analytical balance, and other equipment.  The study would be conducted from different perspectives including such things like: underlying principles, important components, historical and economic points, instrument performance, design, typical application areas, pragmatic issues and son on.

For further information visit www.bgsu.edu.… Read the rest

We’ve blogged about the do’s and dont’s when it comes to analytical balance use and chemical handling in the lab.  We’ve however not established it with a live case study.  Here is an example of what can result from improper handling of chemicals and sub-optimal use of the analytical balance.  It started with the detection of abnormally high levels of arsenic in the urine of an employee at an affiliated laboratory.  Investigations revealed that the entire process of using the analytical balance and weighing flouted several best practices.  In fact the contamination was so high that an external decontamination crew had to be called in.  The article reinforces the need to follow best practices when handling chemicals.

For further information visit risk.arizona.edu.… Read the rest

Here is instructions for an experiment to indirectly measure the mass of a bolt.  There is a whodunit element to the exercise in that the instructions do not give clear directions as how to go about measuring the mass since the bolt is attached to a nut that cannot be removed. A number of hints are provided in the copy and also suggestions on determining the mass using a balance beam or an analytical balance.  The choice of method and equipment to use is largely left to the discretion of the student with only the goals being stated and a few focus questions being asked to help establish the direction in which to move the experiment.  Give it a try and pop your answer in the comments below.

For further information visit www.wpi.edu.… Read the rest

Regulatory bodies are increasingly asking for uncertainty estimates in the measurements from testing and calibration labs.  There is also a lot of confusion as to the correct approach to take when determining uncertainty for a precision scale.  Devices like the analytical balance are especially confusing.  This paper examines this problem. The primary issue is the inconsistency of terminology used. To compound that manufacturer specifications do not provide estimates of the uncertainty.  The general literature on the subject cite several ways to estimate uncertainty which is highlighted in the paper along with a discussion on the advantages and disadvantages of the various methods for estimating uncertainty.

For further information visit www.nationalchildrensstudy.gov.… Read the rest