What Makes a “Good” Buffer?

Buffers are often overlooked and taken for granted by laboratory scientists, until the day comes when a bizarre artifact is observed and its origin is traced to a bad buffer.

The simplest definition of a buffer is a solution that resists changes in hydrogen ion concentration as a result of internal and environmental factors. Buffers essentially maintain pH for a system. The effective buffering range of a buffer is a factor of its pKa, the dissociation constant of the weak acid in the buffering system. Many things, such as changes in temperature or concentration, can affect the pKa of a buffer.

In 1966, Norman Good and colleagues set out to define the best buffers for biochemical systems (1). By 1980, Good and his colleagues identified twenty buffers that set the standard for biological and biochemical research use (2,3).  Good set forth several criteria for the selection of these buffers: Continue reading “What Makes a “Good” Buffer?”

A Periodic Table with Heart

It seems that there is no subject immune to organization into a periodic table. A brief Google search reveals periodic tables for everything from beer to typefaces and from art to visualization methods. If a subject can be organized into groups with common properties, or even if it cannot, it appears that it can be made to fit the format.

In amongst all the geeky, funny and just plain weird periodic tables, the old familiar one is undergoing something of resurgence as well. For example, there are several interactive periodic tables for the iPad where you can view any number of characteristics of each element with a tap of the finger, it is now easier than ever to find out everything you will ever need to know about Barium, Potassium, or Neon, to name but a few.

But for me (and a few million other YouTube visitors) one periodic table stands head and shoulders above them all—The Periodic Table of Videos, produced by journalist Brady Haran, Prof. Martyn Poliakoff and others at the University of Nottingham. As the name suggests, this periodic table contains videos introducing each element, demonstrating the properties of each and including interesting anecdotes about their discovery or use. In a recent Science article, Haran and Poliakoff state that all 118 videos were shot over a 5-week period. There were no storyboards or scripts, they simply filmed the scientists talking about each element and demonstrating the important characteristics. The result of this approach is astonishingly engaging. And the informal style is highly successful in communicating the passion and enthusiasm of Dr. Poliakoff and his colleagues for their subject. Try to watch this Sodium video to the end without smiling—-I don’t think it can be done. Continue reading “A Periodic Table with Heart”