Re: what are some methods on how to work out how much iron there is in tea?

Hello,

If you have access to a library, a lot of very useful analytical 
information can be found in Analytical Abstracts.  In the indices you may 
try searching for a few key words like iron, tea etc. Additionally, there 
are many good analytical text books which deal with Atomic Spectrometry. 

The techniques for analysis of iron usually involve Atomic Spectrometry.  
This is a family of techniques which include Atomic Absorption, Atomic 
emission and Inductively Coupled Plasma (ICP).  These techniques involve 
the apiration of a liquid into the nebuliser of the spectrometer.  The 
nebulised liquid is then drawn into a hot flame or a plasma where gaseous 
atoms are formed.  In the case of Atomic Emission (which includes ICP) the 
energy from the flame or plasma causes the atoms to populate an 
electronicaly excited state.  The excited atoms relax back to the ground 
state and emit a characteristic wavelength (this is the same principle as 
flame tests, and sodium lamps used to light the streets of many towns and 
cities).  The intensity of emitted radiation is proportional to the 
concentration of the metal ions in solution.  It is more likely that you 
would analyse for iron using Atomic Absorption (AA).  Here, the gaseous 
atoms (in the ground state this time) within the flame absorb radiation 
from a source, usually a Hollow Cathode Lamp (HCL) which is specific to 
the element of interest.  For example, if you where analysing for iron, 
you would employ the radiation from an iron HCL.  The amount of radiation 
absorbed is then proprational to the concentration of iron.

There are other ways to analyse iron, but atomic Spectrometry would 
usually be the first choice.

Hope this is useful.

Steve Lancaster.