J. Planar Chromatogr. 24, 428-434 (2011). HPTLC of 6-benzyl-, 6-methyl-, and 6-propyl-2-thiouracil and spiked urine samples on silica gel with methanol in a horizontal chamber saturated for 15 min at ambient temperature. Detection by spraying with a freshly prepared mixture of 4 % sodium azide and 1 % starch solution adjusted to pH 5.5, followed by exposure to iodine vapor for 5 s. Quantitative evaluation by use of an office scanner at 300 dpi resolution. The images were inverted and stored in the form of 24-bit-true color images, which were analysed by TLSee software. The determination range was 7-16 pmol/zone, 80-160 nmol/mL urine, or 133-266 nmol/mL serum. The recovery was between 93-106 %. The LOQ was 4 pmol/zone for the studied thiouracils in three investigated matrices.

J. Planar Chromatogr. 25, 338-343 (2012). HPTLC of fluvoxamine in the presence of degradation products on silica gel with ethyl acetate - toluene - methanol - ammonia 14:4:2:1. Quantitative determination by absorbance measurement at 254 nm. The hRf of fluvoxamine was 63. Linearity was in the range of 100-1000 ng/zone. Limits of detection and quantification were 10 and 100 ng/zone. The intermediate/inter-day/intra-day precision was below 0.9 % (n=6). Recovery was between 96.9 and 100.1 %.

J. Liq. Chromatogr. Relat. Technol. 36, 1323-1329 (2013). HPTLC of amlodipine (1) and perindopril (2) in bulk powder and tablets on silica gel with n-butanol - water - glacial acetic acid 4:5:1. Quantitative determination by absorbance measurement at 365 nm and 215 nm, for (1) and (2), respectively. The hRf values for (1) and (2) were 72 and 48, respectively. Linearity was 1-6 µg/mL for (1) and 2-10 µg/mL for (2). LOD and LOQ were 0.28 and 0.86 µg/mL for (1) and 0.24 and 0.75 µg/mL for (2), respectively. The interday and intra-day precisions were below 1.3 % (n=3). Recovery (by standard addition) was 98.0-99.6 % for both (1) and (2). Comparable results were obtained when compared with validated HPLC and first-derivative spectrophotometry methods, resulting in short scan time, large sample capacity, and use of minimal volume of solvent.

J. Liq. Chromatogr. Relat. Technol. 37, 367-378 (2014). TLC of curcumin (1), piperine (2), and boswellic acid (3) in polyherbal transdermal patch on silica gel aluminum foils with chlorofom - ethyl acetate - formic acid 75:60:2. Quantitative determination by absorbance measurement at 540 nm. The hRf values for (1) to (3) were 48, 52 and 61, respectively. The linear calibration range was selected at very high amounts (1-15 µg/zone for (1) to (3)) despite the low LOD and LOQ of 0.06 and 0.2 ng/zone for (1), 0.31 and 0.95 ng/zone for (2) and 14.22 and 43.10 ng/zone for (3). Average recovery (by standard addition) was in the range of 98-99 % for (1) to (3). Intermediate intra- and inter-day precision was below 0.1 % (n=6).

J. Liq. Chromatogr. Relat. Technol. 38, 1113-1120 (2015). HPTLC of orbifloxacin (1), danofloxacin (2), ciprofloxacin (3), norfloxacin (4), enrofloxacin (5), marbofloxacin (6), difloxacin (7) and ofloxacin (8) on silica gel with 1,4-dioxane - ammonia - tetrahydrofuran 6:3:2. Quantitative determination by absorbance measurement at 320 nm. The hRF value was 19 for (4), 23 for (3), 30 for (2), 37 for (8), 40 for (6), 44 for (5), 56 for (1) and 59 for (7). Linearity was in the range of 159-513 ng/zone for (1), 99-238 ng/zone for (2), 97-244 ng/zone for (3), 69-163 ng/zone for (4), 63-170 ng/zone for (5), 103-250 ng/zone for (6), 84-251 ng/zone for (7) and 94-260 ng/zone for (8). LOD and LOQ were 53 and 159 ng/zone for (1), 32 and 98 ng/zone for (2), 32 and 97 ng/zone for (3), 23 and 69 ng/zone for (4), 21 and 63 ng/zone for (5), 34 and 103 ng/zone for (6), 28 and 84 ng/zone for (7) and 31 and 94 ng/zone for (8), respectively. Selection of appropriate viscosity of the mobile phase may be important in obtaining optimal chromatographic separation.

J. Planar Chromatogr. 29, 229-231 (2016). HPTLC of imipenem, meropenem, doripenem and eratapenem on silica gel G with 11 developing systems. Detection by spraying with iodine solution (0.2 g of potassium iodine and 0.4 g of iodine_x000D_ mixed in 20 mL of ethanol and 5 mL of hydrochloric acid), ninhydrin reagent (0.1 % ninhydrin in ethanol) or potassium permanganate solution (1 mg dissolved in 10 mL of water). The hRF values for the studied carbapenems in each developing system ranged between 13 and 58.

J. Planar Chromatogr. 30, 291-298 (2017). HPTLC of cefuroxime axetil and cefepime in human whole blood and urine on silica gel with chloroform – ethyl acetate – glacial acetic acid – water 4:4:1:3 for (1) and ethanol – 2-propanol – glacial acetic acid – water 4:4:1:3 for (2). Quantitative determination at UV 285 nm for (1) and 266 nm for (2). The hRF values for (1) and (2) were 89 and 21, respectively. Linearity was between 3-77 μg/mL for (1) and 3-38 μg/mL for (2). The intermediate precision (n=6) was <2 % for (1) and (2). LOD and LOQ were in the range of 40 and 470 ng/zone. Recovery rate ranged from 95.8 to 101.5 % for (1) and (2).

J. AOAC Int. 3, 708-713 (2018). HPTLC of acetylsalicylic acid (1), hydrochlorothiazide (2), enalapril (3), and atorvastatin (4) in a formulation on silica gel with n-hexane – ethyl acetate – methanol – water – acetic acid 42:40:15:2:1. Quantitative determination by absorbance measurement at 210 nm for (3) and 265 nm for (1), (2) and (4). The hRf values for (1) to (4) were 68, 44, 31 and 54, respectively. Linearity was in the range of 0.600-6.000 μg/zone for (1), 0.058-1.102 μg/zone for (2), 0.505-6.560 μg/zone for (3) and 0.100-1.000 μg/zone for (4). The intermediate precision was below 3 % (n=5). The LOD and LOQ were 0.311 and 0.942 μg/zone for (1), 0.043 and 0.130 μg/zone for (2), 0.331 and 1.003 μg/zone for (3) and 0.044 and 0.135 μg/zone for (4). (Note by the editor: Calibration should start at LOQ, not below.) Recovery was between 97.0 and 101.3 % for (1) to (4).