Extraction, Identification and Determination of Caffeine and Trace Metals in Three Types of Tea Leaves

Determination of Caffeine and Few Metals in Halabja Tea and Comparing with Various Tea Samples in Erbil Markets

“…The conical flask was eventually placed in a steam bath, and the contents were evaporated to dryness at a relatively low heat of the water bath. The container was weighed to determine the crude caffeine amount [29].…”

“…The separating funnel stopper was opened, and the chloroform was collected in a 100 mL beaker and evaporated to dryness in the hood on a water bath. The flask was weighed to determine the crude caffeine amount [29].…”

“…The crucible residue was transferred to a beaker and dissolved in 200 mL of 0.1 M HNO 3 for all types of tea leaves and bags before being filtered, the filtrate was used for the analysis of lithium, sodium, potassium, and calcium elements. The blank solution is 0.1 M HNO 3 [29].…”

“…Purines give sharp absorption at 270 nm, whereas caffeine absorbs at 272.5 nm due to the replacement of three methyl groups on three nitrogen atoms. The development of absorption band 272.5 nm for caffeine is related to the electronic transition of n σ* and π π* where unpaired electrons are abundant on nitrogen atoms and carbonyl groups in addition to double bonds [29].…”