Determination of Calcium Ions in Milk Using Titration
Determination of Calcium ions in milk using titration.
Background Calcium is a mineral which is essential to the human body. In fact 1.5% of the human body is made up of calcium, and not just the obvious uses such as bone and teeth formation but it is also a vital factor in many enzyme reactions, for example blood clotting. It also partakes in the regulation of the hearts rhythm. Lack of the crucial mineral can result in the build up of cadmium and lead, both of which are toxic. along with causing rickets in children, osteomalacia and osteoporosis. over 99% of the human bodies calcium is found in the bones whilst the remaining 1% or so is found in the blood matrix. Calcium can be found in cereals fruits and vegetables and the most obvious dairy products.
Emphasis and Technique My aim for this experiment is to discover if it is possible to determine the amount of calcium in a sample of milk. Also to compare two different types of milk’s calcium content. For this I shall be using full fat milk and semi skimmed milk, to discover which, if either have a higher content of calcium. The amount of calcium in a solution can be determined using titration. In this case it will be complexometric titration against EDTA (ethylenediamine tetraacetic acid). EDTA is a hexaprotic acid, meaning that each of the amines nitrogen’s and each of the acid’s oxygen’s can donate one electron pair. There are four carboxylic acid groups and two amine groups, allowing a total of six attachments points, hence it being ‘hexa’protic. EDTA is a chelating agent, which works by ‘binding’ with metal ions, forming complexes. 
This diagram shows the six points of attachment in red and green. Ca 2+ + EDTA 4- ® CaEDTA 2- This equation shows that the EDTA reacts with the metal ion, which in this case is calcium on a 1:1 ratio, therefore it can be worked out however many moles of EDTA is used the calcium will be the same. To work this
Background Calcium is a mineral which is essential to the human body. In fact 1.5% of the human body is made up of calcium, and not just the obvious uses such as bone and teeth formation but it is also a vital factor in many enzyme reactions, for example blood clotting. It also partakes in the regulation of the hearts rhythm. Lack of the crucial mineral can result in the build up of cadmium and lead, both of which are toxic. along with causing rickets in children, osteomalacia and osteoporosis. over 99% of the human bodies calcium is found in the bones whilst the remaining 1% or so is found in the blood matrix. Calcium can be found in cereals fruits and vegetables and the most obvious dairy products.
Emphasis and Technique My aim for this experiment is to discover if it is possible to determine the amount of calcium in a sample of milk. Also to compare two different types of milk’s calcium content. For this I shall be using full fat milk and semi skimmed milk, to discover which, if either have a higher content of calcium. The amount of calcium in a solution can be determined using titration. In this case it will be complexometric titration against EDTA (ethylenediamine tetraacetic acid). EDTA is a hexaprotic acid, meaning that each of the amines nitrogen’s and each of the acid’s oxygen’s can donate one electron pair. There are four carboxylic acid groups and two amine groups, allowing a total of six attachments points, hence it being ‘hexa’protic. EDTA is a chelating agent, which works by ‘binding’ with metal ions, forming complexes. 
This diagram shows the six points of attachment in red and green. Ca 2+ + EDTA 4- ® CaEDTA 2- This equation shows that the EDTA reacts with the metal ion, which in this case is calcium on a 1:1 ratio, therefore it can be worked out however many moles of EDTA is used the calcium will be the same. To work this