Chinese J. of Anal. Chem. (Fenxi Huaxue) 39 (9), 1427-1431 (2011). Description of a method for determination of residual glycerides in biodiesel by TLC-thermally assisted hydrolysis and methylation GC (TLC-THM-GC) with a pyrolysis-GC system. The residual glycerides were determined based on the total peak area of the fatty acid methyl esters formed. TLC of glycerides on silica gel with toluene - acetone 23:2. Detection by exposure to iodine vapor. The zones of interest were scraped off the plate and extracted with ethyl acetate. GC quantification of the glycerides after methylating the mixture of 3 µL methanolic trimethylsuIfonium hydroxide (0.1 mol/L) and 3 µL sample extract at 350 °C. In the presence of organic alkali and trimethylsuIfonium hydroxide the glycerides are converted into their corresponding fatty acid methyl esters. The linearity for monoglyceride, diglyceride and triglyceride was between 60-2000 mg/L, with %RSD of 3.2-7.2 % at a level of 250 mg/L, the regression coefficients were between 0.9863-0.9993. The proposed method was successfully applied for the determination of the content of residual glycerides and the composition of fatty acids in biodiesel samples produced from rape oil and palm oil.

J. Liq. Chromatogr. Relat. Technol. 34, 920-927 (2011). TLC of flumequine in milk on silica gel with dichloromethane - methanol - 2-propanol - 25 % aqueous ammonia 3:3:5:2. Bioautography by dipping into an Escherichia coli bacteria suspension for 5 h at 37 ºC. After incubation, the plates were sprayed with 0.2 % MTT ([3-(4,5-dimethyldiazol-2-yl)-2,5 diphenyltetrazolium bromide] aqueous solution and incubated for about 30 min at 37 ºC. The new procedure gave better recoveries of flumequine residues from milk compared with the previous method.

J. Planar Chromatogr. 24, 218-221 (2011). HPTLC of alfuzosin hydrochloride (ALF) and dutasteride (DUTA) in the bulk drug and in a tablet formulation on silica gel with toluene - methanol - dichloromethane 6:1:1 + 1 drop triethylamine. Quantitative determination by densitometry at 247 nm. The hRf of ALF was 46 and of DUTA 65. Linearity was between 300-600 ng/band for ALF and 500-100 ng/band for DUTA. LOD and LOQ were 100 and 200 ng/band for ALF and 300 and 400 ng/band for DUTA. Precisions (%RSD) for repeatability of application were 1.8 and 1.5 % for ALF and 1.5 and 1.4 % for DUTA. The inter-day and intra-day precision (%RSD, n = 6) was 1.0 and 0.9 % for ALF and 1.7 and 0.8 % for DUTA, respectively. Recovery (by standard addition) was between 98.9-101.6 % for both compounds.

J. AOAC Int. 93, 811-819 (2010). HPTLC of olanzapine on silica gel (prewashed twice with methanol) with methanol - ethyl acetate 4:1 in a twin-trough chamber saturated for 20 min at 25 +/- 2 °C. Quantitative determination by densitometry in absorbance mode at 285 nm. The hRf was 35. Linearity was between 100 and 600 ng/band for olanzapine. LOD was 24 ng/band and LOQ 91 ng/band. The average recovery (n = 6) was 100.4 %. The %RSD of intra-day and inter-day precision (n = 5) was between 0.2-1.4 %.

J. Liq. Chromatogr. Relat. Technol. 34, 1925-1937 (2011). HPTLC of p-hydroxy benzoic acid (1), chrysoplenol-D (2), p-methoxy benzoic acid (3) and casticin (4) in the aerial parts of Vitex trifolia on silica gel with chloroform - methanol 24:1 + 1 drop formic acid. Quantitative determination by absorbance measurement at 254 nm. The hRf values of compounds (1) - (4) were 25, 31, 63 and 87, respectively. LOD and LOQ were found to be 18-58 ng/zone for (1), 39-132 ng/zone for (2),15-52 ng/zone for (3) and 33-111 ng/zone for (4). Repeatability and reproducibility (%RSD) for (1)-(4) were found in the range of 0.8-1.2 % and 1.2-1.3 %, respectively. Recoveries were obtained in the range of 94.0-101.1 %, 97.8-102.0 %, 95.1-100.1 %, and 97.6-100.3 % for compounds (1) - (4), respectively.

J. Liq. Chromatogr. Relat. Technol. 35, 1346-1363 (2012). HPTLC of acetylsalicylic acid in tablets on silica gel with n-hexane – diethyl ether – acetic acid 7:2:1. Quantitative determination by absorbance measurement at 200 nm. The hRf value of acetylsalycilic acid was 18 and selectivity regarding matrix was given. Linearity was between 4.7 and 19.2 µg/zone. The intermediate/inter-day/intra-day precision was below 2 % (n=3). The limit of detection and quantification was 160 and 480 ng/zone, respectively. Recovery (by standard addition) was 100.4 %.

J. Planar Chromatogr. 25, 374-379 (2012). HPTLC of atazanavir sulfate (1) and ritonavir (2) in combined dosage forms on silica gel with toluene - methanol - glacial acetic acid - ethyl acetate 14:1:3:4. Quantitative determination by absorbance measurement at 254 nm. The hRf values for (1) and (2) were 50 and 63, respectively. Linearity was in the range of 30-300 ng/zone for (1) and 10-100 ng/zone for (2). The limit of detection and quantification was 16 and 49 ng/zone for (1) and 18 and 55 ng/zone for (2), respectively. The intermediate/inter-day/intra-day precision was below 0.7 % (n=6). Recovery for (1) and (2) was in the range of 99.6-100.0 %.

J. Planar Chromatogr. 25, 575-580 (2012). HPTLC of echioidinin-5-O-beta-D-glucopyranoside in Andrographis echioides on silica gel with chloroform - methanol 31:9. Quantitative determination by absorbance measurement at 254 nm. Linearity was in the range of 200-1400 ng/zone. Limits of detection and quantification were found to be 54 and 68 ng/zone, respectively. Recovery (by standard addition) was 96.7 %.