Caffeine

Caffeine, theobromine and theophylline

Inspite of the slight differences in structure the three xanthines are easily separated by micellar electrokinetic chromatography. The sensitive direct detection is possible at 215 nm. The determination of caffeine and the other xanthines is made in several samples with different matrices.

Caffeine standard solution – 10 mg/l

• Separation: MEKC
• Electrolyte: Borate-SDS
• Capillary: fused silica, 50 µm ID, 64 cm in total
• Injection: 10 s, 50 mbar
• Detection: direct UV, 215 nm
• Description: The standard solution contains 10 mg/l caffeine, theobromine and theophylline, each.

Download: Koffein_1.pdf

Caffeinated protein powder as food supplement

• Separation: MEKC
• Electrolyte: Borate-SDS
• Capillary: fused silica, 50 µm ID, 64 cm in total
• Injection: 20 s, 50 mbar
• Detection: direct UV, 200 nm
• Description: The sample was weighed and diluted with water. After homogenization in an ultrasonic bath, a light brown liquid was obtained. This solution was injected unfiltered.

The sample can be measured easily and reproducibly even with the high protein content. The caffeine peak is very well separated from the protein matrix. In the PDF (348 KB) it is shown that caffeine can be determined without problems in the protein matrix. The identity was confirmed by the spectral data of caffeine in the sample solution and standard solution.

Download (348 KB): caffeine-proteine.pdf

Caffeine in energy drink

• Separation: MEKC
• Electrolyte: Borate-SDS
• Capillary: fused silica, 50 µm ID, 64 cm in total
• Injection: 20 s, 50 mbar
• Detection: direct UV, 215 nm
• Description: The energy drink was diluted 1:20.

Download: Koffein_2.pdf

Caffeine in Cola light

• Separation: MEKC
• Electrolyte: Borate-SDS
• Capillary: fused silica, 50 µm ID, 64 cm in total
• Injection: 20 s, 50 mbar
• Detection: direct UV, 215 nm
• Description: The Cola was diluted 1:20.

Download: Koffein_3.pdf

Caffeine in instant coffee

• Separation: MEKC
• Electrolyte: Borate-SDS
• Capillary: fused silica, 50 µm ID, 64 cm in total
• Injection: 20 s, 50 mbar
• Detection: direct UV, 215 nm
• Description: 50 mg of coffee powder were extracted with 10 ml of cold pure water and then tenfold diluted.

Download: Koffein_4.pdf

Caffeine in chocolate beans

• Separation: MEKC
• Electrolyte: Borate-SDS
• Capillary: fused silica, 50 µm ID, 64 cm in total
• Injection: 20 s, 50 mbar
• Detection: direct UV, 215 nm
• Description: The amount of theobromine in chocolate beans is an indication for the amount of cocoa. 500 mg chocolate beans were homogenized in 10 ml pure water, filtered and diluted 1:2.

Download: Koffein_5.pdf

Caffeine in shampoo

• Separation: MEKC
• Electrolyte: Borate-SDS
• Capillary: fused silica, 50 µm ID, 64 cm in total
• Injection: 20 s, 50 mbar
• Detection: direct UV, 215 nm
• Description: 50 mg shampoo were extracted in 10 ml pure water.

Download: Koffein_6.pdf

Caffeine and taurine in face cream

• Separation: MEKC
• Electrolyte: Borate-SDS
• Capillary: fused silica, 50 µm ID, 64 cm in total
• Injection: 20 s, 50 mbar
• Detection: direct UV, 195 nm
• Description: 50 mg face cream were extracted in 10 ml pure water.

Download: Koffein_7.pdf

Caffeine, paracetamol and vitamin C in cold remedy

• Separation: MEKC
• Electrolyte: Borate-SDS
• Capillary: fused silica, 50 µm ID, 64 cm in total
• Injection: 20 s, 50 mbar
• Detection: direct UV, 195 nm
• Description: The content of the capsule was dissolved in pure water.

Download: Koffein_8.pdf

Caffeine und theobromine in green tea

• Separation: MEKC
• Electrolyte: Borat-SDS
• Capillary: fused silica, 50 µm ID, 64 cm in total
• Injection: 10 s, 50 mbar
• Detection: direct UV, 195 nm
• Description: 200 mg tea were extracted in10 ml hot water and then diluted 1:5.

Download: Koffein_9.pdf

Caffeine and theobromine in black tea

• Separation: MEKC
• Electrolyte: Borate-SDS
• Capillary: fused silica, 50 µm ID, 64 cm in total
• Injection: 20 s, 50 mbar
• Detection: direct UV, 195 nm
• Description: 200 mg tea were extracted in10 ml hot water and then diluted 1:5.

Download: Koffein_10.pdf

Caffeine and theophylline in a bar with extract of guarana

• Separation: MEKC
• Electrolyte: Borate-SDS
• Capillary: fused silica, 50 µm ID, 64 cm in total
• Injection: 20 s, 50 mbar
• Detection: direct UV, 195 nm
• Description: 500 mg of the bar were homogenized in 10 ml pure water in an ultrasonic bath. The resulting solution was filtered and then diluted 1:5.

Download: Koffein_11.pdf