Mercury, ultra trace analysis

The presence of mercury - in several forms, and in any substance that we deal with, is a concern raised by the possible toxicity of many of its forms. Environmental analytical laboratories regularly analyze soil, lake water, potable water, seafood, pharmaceutical products, and several other types of samples for mercury contamination.

Such contamination is usually caused by industrial and commercial pollution. As a result, I have personally seen alarming levels of toxic mercury in fish and water samples I analyzed during the past two decades.

This book will deal with the technical aspect of laboratory analysis SOPs and will examine several options.

The emphasis here will be on cold vapour atomic absorption technique whereby mercury ions in an acidic solution are reduced by reaction with stannous chloride to ground state atoms.

The solution is vigorously stirred until the mercury vapor over the solution reaches equilibrium with the mercury left in the solution.

The total Mercury atoms (atomic mercury vapor) is driven {by use of purge gas: nitrogen or argon} into a quartz absorption cell located in the optical path of AAS.

Hg, being in a ground atomic state is amenable to atomic absorption of radiation and Hg atoms are monitored at 253.7 nm wavelength.

This is the basis theory of the SOP. We’ll get into details later.

This book will deal specifically with the laboratory treatment, digestions, complications, side effect and undesired by-products “compounds” that the bench chemist may face and must be aware of, and the tips and advices drawn from personal analytical laboratory experience.

A major part of the paper will reflect on a solid atomic absorption approach. I will still have to touch on related issues that constitute a significant role in the overall success of the analytical chemist in understanding what is happening in the sample at all times.

I also want to comment that while mercury use, as well as many of its treatment techniques are in fact as ancient as the Pharaohs and the Romans; and while recorded history proves that the Egyptians followed by the Greeks and Romans used mercury for cosmetic and medical preparations over five thousand years ago; we are now talking about ppt level, which mocks the expression “splitting hair.”

Indeed, the basic structure of a wet procedure still being used today involving mercury and gold amalgamation is recorded in hieroglyphic and is dated back to year 2800 B.C. It was also the SOP utilized in 1600 BC when Aristotle referred to mercury as liquid silver. This is the root-concept of the method that was recently developed to ppt detection limit with contemporary instrumentation.

This book will lead you through the bench – wet chemistry steps prior to and during the instrumentation component of the SOPs, and will also go through other wet SOPs we still need to use, to understand and to manipulate. The wet – or bench part of the analysis is most significant. Instrumentation can only read what the chemist has written in that test tube.