J. Planar Chromatogr. 10, 303-304 (1997). HPTLC of diltiazem (3-(acetyloxy)-5-[2-(dimethylamino)ethyl]-2,3-dihydro-2-(4-methoxyphenyl)-1,5-benzothiazepin-4(5H)-one) and desacetyldiltiazem on silica with chloroform - cyclohexane - toluene - diethylamine 30:20:20:3. Detection under UV 254 nm. Quantification by densitometry at 240 nm (absorbance). RSD of 2.2 and 0.9% (for two samples containing 0.23 and 0.68% of DAD); recovery (450 ng of D) was 99.7%; repeatability was 1.7%. Also published in Proc. 9th Internat. Symp. Instr. Chromatogr., Interlaken, April 9.-11., 1-4 (1997).

HPTLC with ultraviolet absorption densitometry on preadsorbent layers. Acta Chromatographica No. 7, 124-128 (1997). HPTLC on silica with ethyl acetate - acetic acid 19:1 in a vapor-equilibrated, paper-lined chamber, and on RP-18 with methanol - 0.5 M sodium chloride solution 11:9. Detection and quantification under UV 254 nm. Detection limit 0.25 µg. Recoveries and standard deviation are typical for those obtained for routine use of the method in a pharmaceutical laboratory. The TLC method involves very low solvent usage on a per sample basis compared to HPLC, leading to savings in purchase and disposal costs, and the ability to analyze multiple samples on a single plate containing only three standard zones permits very high sample throughput. Use of both NP- and RP-TLC provides excellent confirmation of qualitative and quantitative results.

J. Planar Chromatogr. 11, 222-224 (1998). HPTLC of propantheline bromide, 9-hydroxypropantheline bromide, xanthone, xanthoic acid on RP-18, pre-washed with methanol, with methanol - 0.1 M acetate buffer (pH 3.5) containing 25 mM sodium pentanesulfonate 31:9, in a chamber presaturated for 10 min. Densitometry by absorbance at 268 nm. Accuracy (expressed as percentage error) of the method was in the range of 0 - 4.5% and precision (expressed as % RSD) was in the range of 2 - 6%. Sensitive, accurate, and stability-indicating HPTLC method.

J. Planar Chromatogr. 12, 202-206 (1999). HPTLC of ciprofloxacin hydrochloride and tinidazole on silica gel with chloroform - methanol - toluene - triethylamine - water 20:20:16:15: 4. Detection and quantification by densitometry at 327 nm. New simple, precise, accurate, rapid and stability-indicating HPTLC procedure.

J. Planar Chromatogr. 12, 361-364 (1999). HPTLC of paracetamol and mefenamic acid on silica gel with toluene - acetone - methanol 8:1:1. Detection and quantification by densitometry at 263 nm. The linearity ranges were 120-360 ng/µl; RSD between 0.41 and 0.78%; recoveries were in the range of 95.50-103.60%. New simple, precise, accurate and rapid HPTLC method.

J. Sliwiok (ed.): Acta Chromatographica 10, 222-230 (2000). HPTLC of complexes of diclofenac sodium with Cu2+, Co2+, Ni2+, Mn2+, Fe3+, Fe2+, and Pd2+ on RP18W and CN layers with different water - methanol mixtures. Rf values increased linearly with increasing concentration of methanol in the mobile phase. Visualization under UV 254 nm

Proc. Intern. Symp. on Planar Separations, Planar Chromatography 2001, pp. 81-90. An amine in dichloromethane was applied as a single spot to a silica gel plate. A solution of a sulfonyl chloride was then applied to the same area. The solvent was allowed to evaporate from the plate which was then irradiated in a microwave oven. TLC with methanol - dichloromethane 1:9. Visualization under UV 254 nm or by spraying with ninhydrin. Product spots could be analyzed by MS resp. by NMR and GCMS after elution (typical reference standards used were sulfaguanidine, sulfapyridine, sulfathiazole, sulfadiazine, sulfamethoxazole and amphotericin). Screening was done with a bacteria suspension of Serracia marcescens or Bacillus subtilis in an agarose containing medium on the TLC plate.

J. Planar Chromatogr. 14, 445-448 (2001). HPTLC of idebenone (2-(10-hydroxydecyl)-5,6-dimethoxy-3-methyl-2,5-cyclohexadiene-1,4-dione) on silica gel with toluene - ether - methanol - triethylamine 8:8:3:1. Densitometry and quantification at 279 nm. Recovery was found to be 100.48%; linear regression of idebenone in the range of 100 to 1000 ng. New simple, specific, and sensitive TLC method.