High Performance Thin Layer Chromatography coupled with Mass spectrometry (HPTLC–MS) is an analytical technique that requires low-level of sample preparation. Here it is illustrated with the determination of quinine in tonic water and caffeine in coffee and cola drinks. Tonic water and the analyzed cola drinks were decarbonized through ultrasonication, and boiled coffee was extracted through an appropriate 0.45 µm PTFE syringe filter. After the initial chromatographic separation, specific bands were eluted with an TLC-MS interface and detected with mass spectrometry.
Caffeine (hRf = 56, m/z = 195.2, 236.2, Figure. 2) and quinine (hRf = 37, m/z = 325.4, Figure. 4) were detected under UV light (254 nm, Figure. 1; 366nm, Figure. 3) and measured by TLC-MS.
Figure 1. (left) Developed plate at 254 nm. Figure 2. (right) Mass spectrum of caffeine in coffee
Figure 3. (left) Developed plate at 366 nm; Figure 4. (right) mass spectrum of quinine in tonic water
These results demonstrate that caffeine and quinine can easily be analyzed by HPTLC-MS with a minimum of sample preparation in coffee, cola drinks or tonic water.