Figure 5

Microfluidics device that can be utilized for automated caffeine amount determination in beverages.

(a) The photograph of a disc for fully automated caffeine detection. The disc design shows detailed microfluidic layout. The number indicates the order of the valve operation and arrows indicate the flow of reagents. The red circles with numbers are normally closed-laser irradiated ferrowax microvalves and the blue circles with numbers are normally open-laser irradiated ferrowax microvalve. (b) The CCD images of the spinning disc at each reaction steps. (c) The calibration curve obtained using the lab-on-a-disc and caffeine solution with known concentration. Each data points are an average of 4 samples tested with 4 different discs. (d) Caffeine concentration measured by fully automated lab-on-a-disc with real beverage samples; Decaf (Caffe Vergnano 1882), Coca-Cola, Red Bull (energy), Coffee (Angelinus Americano) and Espresso (Nespresso Roma). Values are represented as means and error bars as standard deviations (n = 3).