Table 4.

Robustness of the quantitative determination with the TLCyzer app. The numerical values of all 192 individual measurements are listed in Supplementary Table S5.

Modification	API	Mean (n = 6; true value 90%)	Recovery of the respective API (n = 6) (%)	RSD of respective API (n = 6) (%)	Mean recovery of the four APIs (n = 24) (%)	Mean RSD of the four APIs (n = 24) (%)
Standard conditions	Chloroquine	92.1	102.4	2.67	101.0	2.17
	Dexamethasone	89.1	98.9	2.12
	Hydrochlorothiazide	93.1	103.4	1.12
	Metformin	89.3	99.2	2.75
Cropping: full plate with labelling (see Supplementary Fig. S1b)	Chloroquine	93.7	104.1	1.81	102.7	2.17
	Dexamethasone	91.9	102.1	3.31
	Hydrochlorothiazide	93.3	103.6	2.12
	Metformin	90.7	100.8	1.44
Cropping: without labelling (see Supplementary Fig. S1b)	Chloroquine	91.5	101.7	3.63	100.3	2.52
	Dexamethasone	88.9	98.8	2.42
	Hydrochlorothiazide	91.8	102.0	1.82
	Metformin	89.0	98.9	2.22
Manual spot detection	Chloroquine	93.7	104.1	1.84	102.2	2.65
	Dexamethasone	91.9	102.1	3.51
	Hydrochlorothiazide	92.6	102.9	3.57
	Metformin	89.8	99.8	1.66
UV lamp not central	Chloroquine	92.4	102.6	4.51	102.2	3.99
	Dexamethasone	93.2	103.6	4.39
	Hydrochlorothiazide	92.9	103.2	5.07
	Metformin	89.4	99.3	2.00
Low battery charge of UV lamp	Chloroquine	89.3	99.2	1.08	99.0	3.04
	Dexamethasone	87.7	97.4	2.36
	Hydrochlorothiazide	88.5	98.3	5.11
	Metformin	90.9	101.0	3.63
Different box for photo-taking (see Supplementary Fig. S5a)	Chloroquine	90.4	100.4	1.97	100.3	1.37
	Dexamethasone	89.7	99.6	1.29
	Hydrochlorothiazide	91.2	101.3	1.06
	Metformin	89.8	99.7	1.16
Different smartphone model for photography and TLCyzer analysis (see “Methods”)	Chloroquine	88.2	97.9	2.90	99.3	2.88
	Dexamethasone	89.5	99.4	2.86
	Hydrochlorothiazide	89.4	99.3	2.82
	Metformin	90.4	100.4	2.95