Asian Journal of Chemistry 23 (5), 2046-2048 (2011). TLC of alpha- and beta-asarone in Acorus calamus on caffeine modified silica gel (with 10 % caffeine in dichloromethane and dried at 100 °C for 10 min) with toluene - ethyl acetate 93:7. The hRf value of alpha-asarone was 67 and of beta-asarone 77. Quantitative evaluation by absorbance measurement at 313 nm. The linearity was in the range of 50-1000 ng/band for beta-asarone. The alcoholic extracts of samples from different geographical regions were found to contain 0.2-0.8 % of alpha-asarone and 8.7-11.2 % of beta-asarone.

J. Planar Chromatogr. 25, 571-574 (2012). HPTLC of theanine in tea extracts on silica gel with n-butanol - acetone - acetic acid - water 7:7:2:4. Detection by dipping into a ninhydrin reagent for 3 s, followed by heating at 105 °C for 5-15 min. Quantitative determination by analysis of green channels of photographs using the CP Atlas 2.0 software. The hRf of theanine was 35. Linearity was in the range of 1.4-14 ng/zone. The intermediate/inter-day/intra-day precision was below 0.7 % (n=3). Recovery (by standard addition) was between 95.7 and 102.5 %.

J. Planar Chromatogr. 25, 262-268 (2012). HPTLC of paraquat (1), diquat (2), difenzoquat (3), mepiquat (4), and chloromequat (5) in water on silica gel with 1-propanol - methanol - 2.5 N NaCl 1:1:3. Quantitative determination by absorbance measurement between 500 and 535 nm. The hRf values of compounds (1) to (5) were 21, 30 36, 52 and 56, respectively. Limits of quantification were 5 ng/zone for (1), 2 ng/zone for (2), 25 ng/zone for (3), 15 ng/zone for (4) and 9 ng/zone for (5). Recovery rates for compounds (1) to (5) were 50.7, 65.2, 59.6, 45.1 and 33.7 %, respectively.

J. Planar Chromatogr. 25, 475-480 (2012). HPTLC of amlodipine besylate (1), hydrochlorothiazide (2) and olmesartan medoxomil (3) on silica gel with chloroform - ethyl acetate - toluene - methanol - glacial acetic acid 39:39:77:39:6. Quantitative determination by absorbance measurement at 230 nm. The hRf of compounds (1) to (3) were 31, 56 and 81, respectively. Linearity was in the range of 200-4800 ng/band for (1), 100-4000 ng/band for (2) and 200-5200 ng/band for (3). Limits of detection and quantification were 35 and 101 ng/band for (1), 20 and 59 ng/band for (2) and 48 and 144 ng/band for (2), respectively. Intermediate/inter-day/intra-day precision was below 1.0 % (n=6). Mean recovery was between 100.0 and 100.3 % for all active agents.

Chinese J. of Medication & Clinics 12 (6), 768-769 (2012). Alliin (s-allyl-L-cysteine sulfoxide) is a sulfur containing amino acid found in garlic, which has antibacterial and antioxidant activities and is widely used as a component in Chinese drug formulations. For quality control, TLC on silica gel with n-butanol – glacial acetic acid – water 4:1:1, detection by spraying with 0.2 % ninhydrin and heating at 105 ºC for 5 min and viewing in daylight.

Chinese J. Ethnomed. Ethnopharm. (2), 43-44 (2012). Cissus pteroclada Hayata is a TCM herb. Its crude drug dried rattan is effective in relieving rheumatic pains, invigorating the circulation of blood and vein relaxing, and is the main component of the compound preparations for curing rheumatism, lumbar muscle degeneration, limb paralysis, and traumatic injury. TLC of the extracts of the crude drug and its main active component bergeninum on silica gel with chloroform – ethyl acetate – methanol 5:4:2, detection by spraying with 2 % aqueous ferric chloride – 2 % aqueous potassium ferricyanide 1:1, followed by mild heating.

J. Planar Chromatogr. 25, 295-300 (2012). HPTLC of vanillin-ß-D-glucoside (1), p-hydroxybenzaldehyde (2), vanillic acid (3), p-hydroxybenzoic acid (4) and vanillin (5) on silica gel with n-hexane - chloroform - methanol 5:36:4 + 1 drop glacial acetic acid as mobile phase. Quantitative determination by absorbance measurement at 254 nm for (3) and (4), 280 nm for (1) and (2) and 313 nm for (5). The hRf values for compounds (1) to (5) were 9, 62, 57, 42 and 77, respectively. Linearity was in the range of 24-121 ng/band for (1), 7-33 ng/band for (2), 20-102 ng/band for (3), 21-106 ng/band for (4) and 14-70 ng/band for (5). Limits of detection and quantification were 8 and 20 ng/band for (1), 2 and 6 ng/band for (2), 14 and 20 ng/band for (3), 6 and 20 ng/band for (4) and 4 and 8 ng/band for (5), respectively. Intermediate/inter-day/intra-day precision was below 1.4 % (n=6). Mean recovery for the compounds was between 96.8 and 101.4 %.

J. Planar Chromatogr. 25, 301-305 (2012). HPTLC of kaempferol (1) and apigenin (2) in the whole-plant powder of Sida spinosa Linn. on silica gel with dichloromethane - methanol - formic acid 16:2:1. Quantitative determination by absorbance measurement at 340 nm. Linearity was in the range of 150-450 µg/mL for (1) and 50-150 µg/mL for (2). The intermediate/inter-day/intra-day precision was below 2 %. Recovery was 99.5 % for (1) and 99.3 % for (2).