1. The gram-positive test bacterium Bacillus subtilis. J. Planar Chromatogr. 15, 132-137 (2002). Study to determine optimum conditions for culture of a test microbe Bacillus subtilis enabling the authors to establish its use for direct bioautography. It was found that a '5-9-h' broth culture of B. subtilis was suitable. A much shorter incubation time (4-8 h) was sufficient for TLC plates instead of the original 18 h in a previous study. One additional advantage is the possibility to use TLC plates coated with sorbents other than silica gel. TLC of cefazolin on silica gel, aluminium oxide, cellulose, and polyamide.

J. Planar Chromatogr. 18, 455-459 (2005). HPTLC of erythromycin, troleandomycin (oleandomycin triacetate), tylosin, rifamycin B, and rifampicin on silica gel and on RP-18 in a presaturated chamber with wide-ranging mixtures containing 0 to 100 % esters or ketones in dimethyl sulfoxide or hexamethyldisiloxane. Detection by spraying with a mixture of concentrated sulfuric acid and methanol 1:4 followed by heating at 120 °C for 10 min. Chromatographic retention data and a possible retention mechanism are discussed.

J. Planar Chromatogr. 22, 435-437 (2009). TLC of penicillins (benzylpenicillin, ampicillin, and amoxicillin) and cephalosporins (cephalexin, cefoperazone, ceftriaxone, cefixime, and cefadroxil) in powder extracts on silica gel (impregnated with 0.2 % ammonium chloride) with propanol - acetic acid 4:1 and butanol - acetic acid - water 4:1:2. Detection under UV light at 365 nm.

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. 27, 113-119 (2014). HPTLC of sulphadiazine sodium (1) and trimethoprim (2) in medicated fish feed, fish tissues, and in their veterinary pharmaceutical formulation on silica gel with chloroform - toluene - ethanol - glacial acetic acid 9:9:2:2. Quantitative determination by absorbance measurement at 270 nm. The hRF values for (1) and (2) were 48 and 16, respectively. Linearity was in the range of 100-2000 ng/zone for (1) and 100-1000 ng/zone for (2). The intermediate/interday/intra-day precisions were below 3 % (n=3). Mean recoveries for (1) and (2) were 99.6 and 97.9 %, respectively.

J. Planar Chromatogr. 29, 140-144 (2016). HPTLC of atovaquone (1) and proguanil (2) in tablets on silica gel with toluene – methanol – glacial acetic acid 40:10:1. Quantitative determination by absorbance measurement at 254 nm. The hRF values for (1) and (2) were 80 and 22, respectively. Linearity was in the range of 200-2000 ng/zone for (1) and 100-1000 ng/zone for (2). Intermediate precisions were below 1 %. The LOD and LOQ were 41 and 123 ng/zone for (1) and 31 and 94 ng/zone for (2), respectively. Recovery was in the range of 99.5-100.7 % for (1) and 100.1-100.8 % for (2).

J. Planar Chromatogr. 30, 307-312 (2017). HPTLC of artesunate (1) and amodiaquine (2) on silica gel with toluene – acetonitrile – methanol – ammonium acetate – triethylamine 20:10:6:2:1. Detection of (1) by spraying with a mixture of methanol and sulfuric acid 19:1, followed by heating at 75 °C for 5 min. Quantitative determination by absorbance measurement at 503 nm for (1) and 345 nm for (2). The hRF values for (1) and (2) were 35 and 68, respectively. Linearity was between 93 and 280 ng/zone for (1) and 250 and 1250 ng/zone for (2). The intermediate precision (n=6) was <5 % for (1) and 2 % for (2). Recovery rate ranged from 90 to 110 % for (1) and from 98 to 102 % for (2).

J. Chromatogr. 291, 464-470 (1984). TLC of carbapenem antibiotics on silica with chloroform - methanol - 0.01 M phosphate buffer at pH 7.5 8:6:1. Detection by dipping the plate in Ehrlich reagent. Quantification by scanning by absorbance at 575 nm. Also bioautography with comamonas terrigena. Comparison of densitometry with bioautographic analysis.