Improved Sample Pre-treatment for Determination of Caffeine in Tea Using a Cartridge Filled with Polyvinylpolypyrroridone (PVPP)

Simple and Rapid UV Spectrophotometry of Caffeine in Tea Coupled with Sample Pre-treatment Using a Cartridge Column Filled with Polyvinylpolypyrrolidone (PVPP)

“…We have previously reported that the pre-treatment of tea brew using a PVPP cartridge column made the HPLC analysis of tea caffeine very simple and precise. 24) However, the HPLC method does not spread in field analysis by tea cultivators and the medium and small manufacturers of tea leaf products, because it is expensive and needs skilled hands. On the other hand, UV spectrophotometry is a cheaper method than HPLC, and does not need special skill.…”

“…1b). Figure 2 shows HPLC chromatograms 24) of non-treated, PVPP batch-treated and PVPP cartridge-treated green tea samples, which were the same samples used for UV spectrophotometry. In the case of non-treatment, caffeine and four major catechins in green tea were detected, the peaks of which were sharp and well separated.…”

“…Unfortunately, the PVPP pre-column was not applicable to other analytical methodologies such as micro-HPLC, CE and spectrophotometric methods, and the reproducibility of preparing its column seemed poor. In our previous report, 24) we improved the sample pretreatment method using a cartridge column filled with PVPP for the effective removal of tea polyphenols and the simple HPLC analysis of caffeine in tea. The reproducibility of sample pre-treatment using a PVPP cartridge column was satisfactory for the determination of tea caffeine by the HPLC method.…”

Determinação voltamétrica simultânea de paracetamol e cafeína e de ácido ascórbico e cafeína em formulações famacêuticas empregando um eletrodo de diamante dopado com boro

“…Vários métodos para a determinação de cafeína têm sido desenvolvidos incluindo espectrofotometria [73][74][75][76] , cromatografia [77][78][79][80][81] , entre outros [82][83][84] As soluções estoques de paracetamol na concentração de 1,0 × 10 -3 mol L -1 foram preparadas previamente ao uso para evitar o processo de hidrólise. Estas soluções foram preparadas dissolvendo-se 0,0194 g de paracetamol em 100 mL de tampão acetato pH 4,5.…”