J. Planar Chromatogr. 27, 102-106 (2014). HPTLC of betulinic acid in the leaves of Vitex negundo on silica gel with toluene - acetone - formic acid 17:3:2. Detection by spraying with anisaldehyde sulfuric acid reagent, followed by heating at 105 ºC for 5 min. Quantitative determination by absorbance measurement at 445 nm. The hRf value for betulinic acid was 42. Linearity was in the range of 200-1200 ng/zone. The intermediate/interday/intra-day precisions were below 1.3 % (n=3). The LOD and LOQ were 6 and 18 ng/zone, respectively. Recovery was in the range of 99.7-101.5 %.

J. Planar Chromatogr. 27, 107-112 (2014). HPTLC of disulfiram on RP-18 with methanol - water 9:1. Detection by spraying with copper(II) sulfate (0.5 mol/L), followed by heating at 50 ºC for 2 min. Quantitative evaluation with an office scanner at 300 dpi followed by image processing with software. The hRf value for disulfiram was 67. Linearity was in the range of 1-10 μg/zone. The intermediate/interday/intra-day precisions were below 1 % (n=6). The LOD and LOQ were 260 and 860 ng/zone, respectively. Recovery was in the range of 92.4-102.0 %.

J. Liq. Chromatogr. Relat._x000D_ Technol. 37, 2956-2970 (2014). HPTLC of albendazole (1), amodiaquine (2), artesunate (3), acyclovir (4) and amoxicillin (5) on silica gel with toluene - ethyl acetate - glacial acetic acid 5:2:4 for (1), ethyl acetate - methanol - ammonia hydroxide 24:3:1 and ethyl acetate - acetone - glacial acetic acid 189:40:1 for (2) and (3), ethanol - ammonia - water 7:1:2 for (4) and ethanol - water - glacial acetic acid 4:5:1 for (5). Quantitative determination by absorbance measurement at 254 nm for (1) to (5). The hRF values for (1) to (5) were 63, 75, 34, 69 and 82, respectively. Mean recoveries were in the range of 98-104 % for (1) to (5)._x000D_

by high-performance thin-layer chromatography) (Chinese). J. Chinese Trad. Patent Med. 35 (12), 2752-2754 (2013). Chimonanthus nitens Oliv. is a plant of the Calycanthaceae family growing in Jiangxi and Anhui areas of China. Pharmacological studies showed that the chemical constituents of the extracts of its dry leaves are volatile oils, alkaloids, flavonoids, coumarins, etc. The dry leaves are used clinically as the main ingredient drug in TCM prescriptions for the treatment of infantile cough, respiratory tract infection, hand foot and mouth disease and chronic pelvic inflammatory disease, etc. For quality control, HPTLC of the sample extracts and the standards cineole, linalool and beta-caryophyllene on silica gel firstly with chloroform – methanol 9:1 to 5 cm and then with petroleum ether (30-60 °C) – ethyl acetate 10:1 to 10 cm, detection by spraying with 1 % vanillin in sulfuric acid – ethanol 1:4 and heating at 110 °C. Quantitative determination by densitometric evaluation at 606 nm for cineole and linalool and 545 nm for beta-caryophyllene using external standard calibration method. The content of the total unknown components is also given taking linalool as the calibration standard. Validation of the method by investigation of its linearity range (for cineole 0.7-11.4 µg/zone, r=0.990, n=7; for beta-caryophyllene 0.7-10.9 µg/zone, r=0.992, n=7; for linalool 1.8-18.0 µg/zone, r=0.990, n=7), precision (%RSD (n=6) 3.9 %, 1.5 % and 0.6 % for cineole, beta-caryophyllene and linalool, respectively), stability (within 30 min, %RSD (n=6) 2.0 %, 3.0 % and 3.3 % for cineole, beta-caryophyllene and linalool, respectively) and reproducibility (%RSD (n=6) 2.7 %, 4.4 % and 3.2 % for cineole, beta-caryophyllene and linalool, respectively). The recovery for cineole was 82.3-93.4 % (%RSD (n=3) 2.6-4.1 %), for beta-caryophyllene 86.1-96.7 % (%RSD (n=3) 2.2-3.6 %) and for linalool 95.8-109.8 % (%RSD (n=3) 1.9-2.9 %). Some unknown separated components need to be identified in a further study.

J. Planar Chromatogr. 28, 42-47 (2015). HPTLC of (1) homoeriodictyol and (2) persicogenin in the methanol extract of the aerial parts of Rhus retinorrhoea and Rhus tripartita on silica gel with toluene - ethyl acetate - methanol 16:4:1. Quantitative determination by absorbance measurement at 293 nm. The hRF values of (1) and (2) were 30 and 48. Linearity was between 100 and 800 ng/zone for both, (1) and (2). The intermediate intra-day and inter-day precisions were below 2 % (n=6). The LOD and LOQ were 26 and 77 ng/zone for (1) and 31 and 92 ng/zone for (2), respectively. Recoveries were in the range of 98.9-99.5 % for (1) and 98.3-99.2 % for (2).

J. Planar Chromatogr. 27, 398-402 (2014). HPTLC of (1) permethrin and (2) fenpropathrin in water samples on silica gel with petroleum ether (60-90 °C) - ethyl acetate - dichloromethane 192:5:3. Detection by spraying with 10 mL of phosphomolybdic acid solution (7%, w/v, in ethanol), followed by heating at 170 °C for 10 min. The hRF values of (1) and (2) were 52 and 34, respectively. Linearity was in the range of 8.7-30.6 ng/mL for (1) and 5.4-19.1 ng/mL for (2). The intermediate precision was below 2 % (n=5) . The LOD and LOQ were 0.44 and 1.47 ng/mL for (1) and 0.56 and 1.88 ng/mL for (2), respectively. Average recoveries for (1) and (2) were 92.5 and 95.6 %, respectively.

J. Planar Chromatogr. 27, 416-419 (2014). HPTLC of (1) cotinine and (2) trans-3'-hydroxycotinine in urine on RP-18 with acetonitrile - water 4:1. Quantitative determination by absorbance measurement at 260 nm. Linearity was in the range of 65-325 ng/zone (at a low calibration range) and 325-1300 ng/zone (at a high calibration range) for (1) and 62.5-312.5 and 312.5-1250 ng/zone for (2). The intermediate precisions were below 9 % (n=3). The LOD and LOQ were 13 and 38 ng/zone for (1) and 17 and 50 ng/zone for (2), respectively.

J. Sep. Sci. 38, 592-598 (2015). HPTLC of erythrocentaurin on silica gel with toluene - ethyl acetate - formic acid 40:9:1. Quantitative determination by absorbance measurement at 230 nm. The hRF value of erythrocentaurin was 54. Linearity was in the range of 200-1500 ng/zone. LOD and LOQ were 60 and 180 ng/zone, respectively. Intra-day and inter-day precision was below 1 % (n=3). Recoveries were between 97 and 99 %.