L-Theanine CAS 3081-61-6 Assay 98.0-102.0% (HPLC) Factory

Operation Procedures for Test Standard
1 Apparatuses
1.1 Oven
1.2 Resistance stove case
1.3 High efficiency liquid chromatograph
1.4 Rotation apparatus
2. Operation Methods
2.1 Characters
2.1.1 Eyes: White crystalline powder, odorless, a little sweet characteristic taste.
Soluble in water, insoluble in ethanol, ether
2.1.2 Solution Appearance (1.0g/20ml H2O): colourless, transparent.
2.1.3 Melting point: 202-215℃ according to ChP2010 (appendixⅦC)
2.2 Loss on drying
2.2.1 apparatus, equipment
2.2.2.1 weighing bottle with cover on grinding mouth-diameter: 50mm height: 30mm
2.2.2.2 Galvanothermy constant temperature drying case, able to keep temperature 105±2℃.
2.2.2 Analysis steps
Weigh 1g sample with precision to .0002g, put into weighing bottle dried to constant weight in105±2℃ in advance,slightly open the cover, and put into the drying case near level position of thermometer's mercury ball, until constant weight in 105±2℃. Take final test data as test result. The loss weight is not over 0.5% based on ChP2010 (appendixⅨG)
2.2.3 Analysis result description
Water(H2O)(X1),with mass percentage (%) as follows:
            m1－m2
X1＝——————×100
              m
m1 — mass for weighing bottle+sample before drying g;
m2 — mass for weighing bottle+sample after drying g;
m — sample mass g.
2.3 Residual on ignition: according to ChP2010 (appendix ⅨJ), max. 0.1%.
2.4 Chloride: weigh sample 0.5g, add thin nitric acid 10ml. After dissolving, add water to 50ml. Based on ChP2010 (appendix ⅨC), compared with comparison solution made by standard sodium chloride 10.0ml, not over (0.020%).
2.5 pH value: Weigh the sample 1g, put into 100ml volume flask, and add proper distilled water for dissolving and diluting to scale. With clean beaker taking qualified solution around 50ml ,and corrected acidity meter testing directly, pH should be 5.0~6.0 based on ChP2010 (appendix ⅦG)
2.6 Specific Rotation: Take sample 2.5g dissolved by distilled water and diluted to 50ml,and adjust solution temperature to 20℃, put into 1dm rotation tube.Test based on ChP2010 (appendix ⅦE), the specific rotation should be +7.7° - +8.5°.
2.7 Arsenic content: Take sample 1.0g, put into bottle A ,and according to preparation of standard arsenic spot, from "add potassium iodide reagent 5ml”on, operate ChP2010 (appendix ⅨF) (No.1), and make comparison between made arsenic spot and the counterpart made by standard arsenic solution 4.0ml,not more deeper(4ppm)
2.8 Heavy metals: Take sample1.0g, after dissolving with distilled water 20ml, add acetate buffer (pH3.5) 2ml and suitable water to 25ml, test based on ChP2010 (appendix ⅨE) (No 1),the heavy metal cannot be over 10 ppm.
2.9 Assay
2.9.1 Apparatus: high-efficiency liquid chromatograph.
2.9.2 Reagents
2.9.2.1 Acetonitrile (chromatogram grade).
2.9.2.2 Phosphorus acid (analysis grade).
2.9.3 Standard sample
2.9.4 Chromatogram conditions
2.9.4.1 Chromatogram pole: filling L1 (C18 pole),4.6 mm×250mm
2.9.4.2 Flow phase: acetonitrile: 1% phosphorus acid (5:95)
2.9.4.3 Detection wave length: 199nm
2.9.4.4 Flow speed: 1ml/min
2.9.4.5 Sample injection quantity: 20μL.
2.9.5 Standard sample solution
Take L-Theanine standard sample 0.5g, precisely weigh, and dissolved with flow phase and diluted to 50.0ml. Precisely take 2ml, put into 50ml volume flask, and diluted to scale with flow phase。
2.9.6 Intended sample solution
Take sample 0.5g, precisely weigh, and dissolved with flow phase and diluted to 50.0ml. Precisely take 2ml,and put into 50ml volume flask,diluted to scale with flow phase.
2.9.7 Test
Prepare apparatus according to operation procedures of high-efficiency liquid chromatograph, after balance, take standard solution and intended solution for injection, record chromatogram until 1.5 times of the peak reservation time.
2.9.8 Calculation formula
Assay(%)＝WsXAiX100%/AsxWi
Ai→ L-theanine peak area of intended sample solution
Ws →standard solution sample weight;
As→L-Theanine peak area of standard solution;
Wi→Intended sample weight;