Fig 1.
Schematic diagram of the quantification algorithm for commercial beverages.
Fig 2.
A) Surface observation of BDD captured by SEM. B and C) Surface roughness of BDD analyzed by AFM. D) Electrochemical stability of BDD measured using CV. E) Cdl measurement of BDD. F) Linier plotting from CV measurement for Cdl estimation.
Fig 3.
Electrochemical caffeine measurement.
A) Results of SWV measurements of NaCl solutions and caffeine suspension solutions. B, C) Results of SWV measurements of commercial caffeine beverages. D) Absorbance measurements of BDD and caffeine solutions and ultrapure water.
Fig 4.
Results of SWV measurements of 10 coffee samples from five companies.
Table 1.
Caffeine quantification results for each algorithm.
Table 2.
Details of graded evaluation.
Table 3.
Error between each predicted value and manufacturer’s published value.
Table 4.
Correct solution rate.
Table 5.
Comparison with other caffeine detection in coffee beverages.