This International Standard specifies a method for the determination by high-performance liquid chromatography (HPLC) of the caffeine content of teas and instant teas. It is applicable to green tea, black tea and decaffeinated tea products.<\/p>\n
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| 3<\/td>\n | TitlePage – Tea and instant tea in solid form\ufffd\u2014 Determination of caffeine content\ufffd\u2014 Method using … <\/td>\n<\/tr>\n | ||||||
| 5<\/td>\n | Foreword – Foreword <\/td>\n<\/tr>\n | ||||||
| 7<\/td>\n | Scope – 1\ufffd\ufffd\ufffd Scope NormativeReference – 2\ufffd\ufffd\ufffd Normative references Clause1 – 3\ufffd\ufffd\ufffd Principle Clause1 – 4\ufffd\ufffd\ufffd Reagents UntitledSubclause2 – 4.1\ufffd\ufffd\ufffd Water UntitledSubclause2 – 4.2\ufffd\ufffd\ufffd Methanol UntitledSubclause2 – 4.3\ufffd\ufffd\ufffd Mobile phase UntitledSubclause2 – 4.4\ufffd\ufffd\ufffd Ethanol\/water mixture <\/td>\n<\/tr>\n | ||||||
| 8<\/td>\n | UntitledSubclause2 – 4.5\ufffd\ufffd\ufffd Magnesium oxide UntitledSubclause2 – 4.6\ufffd\ufffd\ufffd Caffeine stock standard solution UntitledSubclause2 – 4.7\ufffd\ufffd\ufffd Caffeine standard solutions UntitledSubclause3 – 4.7.1\ufffd\ufffd\ufffd Caffeine standard solution\ufffdA UntitledSubclause3 – 4.7.2\ufffd\ufffd\ufffd Caffeine standard solution\ufffdB UntitledSubclause3 – 4.7.3\ufffd\ufffd\ufffd Caffeine standard solution\ufffdC UntitledSubclause3 – 4.7.4\ufffd\ufffd\ufffd Caffeine standard solution\ufffdD Clause1 – 5\ufffd\ufffd\ufffd Apparatus UntitledSubclause2 – 5.1\ufffd\ufffd\ufffd High-performance liquid chromatograph UntitledSubclause2 – 5.2\ufffd\ufffd\ufffd Chromatographic column for HPLC <\/td>\n<\/tr>\n | ||||||
| 9<\/td>\n | UntitledSubclause2 – 5.3\ufffd\ufffd\ufffd Filter UntitledSubclause2 – 5.4\ufffd\ufffd\ufffd Electric heating mantle UntitledSubclause2 – 5.5\ufffd\ufffd\ufffd Flask UntitledSubclause2 – 5.6\ufffd\ufffd\ufffd Anti-bumping granules UntitledSubclause2 – 5.7\ufffd\ufffd\ufffd Condenser UntitledSubclause2 – 5.8\ufffd\ufffd\ufffd Analytical balance Clause1 – 6\ufffd\ufffd\ufffd Sampling Clause1 – 7\ufffd\ufffd\ufffd Preparation of test sample Clause1 – 8\ufffd\ufffd\ufffd Procedure Subclause2 – 8.1\ufffd\ufffd\ufffd General Subclause2 – 8.2\ufffd\ufffd\ufffd Determination of dry matter content <\/td>\n<\/tr>\n | ||||||
| 10<\/td>\n | Subclause2 – 8.3\ufffd\ufffd\ufffd Test portion Subclause3 – 8.3.1\ufffd\ufffd\ufffd Green tea and black tea Subclause3 – 8.3.2\ufffd\ufffd\ufffd Instant tea Subclause2 – 8.4\ufffd\ufffd\ufffd Extraction of caffeine UntitledSubclause3 – 8.4.1\ufffd\ufffd\ufffd Add, to the tea in the flask, UntitledSubclause3 – 8.4.2\ufffd\ufffd\ufffd Mix the contents. Attach the condenser ( UntitledSubclause3 – 8.4.3\ufffd\ufffd\ufffd Remove the flask and contents from the heating mantle and cool to r… UntitledSubclause3 – 8.4.4\ufffd\ufffd\ufffd Leave the flask to stand to allow the contents to settle, then remo… Subclause2 – 8.5\ufffd\ufffd\ufffd Dilution Subclause2 – 8.6\ufffd\ufffd\ufffd Determination Subclause3 – 8.6.1\ufffd\ufffd\ufffd Adjustment of the apparatus Subclause3 – 8.6.2\ufffd\ufffd\ufffd HPLC analysis <\/td>\n<\/tr>\n | ||||||
| 11<\/td>\n | Clause1 – 9\ufffd\ufffd\ufffd Calculation Clause1 – 10\ufffd\ufffd\ufffd Precision Subclause2 – 10.1\ufffd\ufffd\ufffd Interlaboratory test <\/td>\n<\/tr>\n | ||||||
| 12<\/td>\n | Subclause2 – 10.2\ufffd\ufffd\ufffd Repeatability Subclause2 – 10.3\ufffd\ufffd\ufffd Reproducibility Clause1 – 11\ufffd\ufffd\ufffd Test report <\/td>\n<\/tr>\n | ||||||
| 13<\/td>\n | AnnexInformative – Results of interlaboratory test <\/td>\n<\/tr>\n | ||||||
| 14<\/td>\n | Bibliography – Bibliography <\/td>\n<\/tr>\n<\/table>\n","protected":false},"excerpt":{"rendered":" Tea and instant tea in solid form. Determination of caffeine content. Method using high-performance liquid chromatography<\/b><\/p>\n |