Anal. Chim. Acta 690 (2), 148-161 (2011). Chromatographic fingerprinting has been generally accepted as analytical method for the quality control of herbal medicines. This review describes the evolution of the regulations and guidelines on the quality control of herbal medicines, and reviews the established analytical techniques in TLC, HPLC, UHPLC, hydrophilic interaction chromatography, and GC. Emphasis is put on the most recent developments, such as miniaturized techniques, new stationary phases, analysis at high temperatures and multi-dimensional chromatography. The new chemometric data handling techniques are discussed.

Acta Chromatographica 21(4), 631-639 (2009). HPTLC on silica gel with toluene – ethyl acetate – formic acid 45:55:1. The hRf value was 31. Quantification by densitometry at 284 nm. The limit of quantification was 35 ng/band, recovery was 97.6-101.6 %, and precision 2.19 %RSD. The method was applicable for routine analysis and accelerated stability testing of terbinafine in pharmaceutical drug-delivery systems. It can be used as a stability-indicating method because it separated the drug from its degradation products.

Acta Chromatographica 20(3), 497-511 (2008). HPTLC of 3-acetyl-11-keto-beta-boswellic acid (AKBA) on silica gel with toluene – ethyl acetate 7:3 at room temperature (25 ± 2 °C) in a twin-trough chamber with chamber saturation. Quantification of AKBA (hRf 52) by densitometry in absorbance mode at 250 nm. The linearity was in the range of 200–1200 ng/band (r=0.9989), recovery was 99.4-100.2 %, and the limits of detection and quantification were 3 and 9 ng/band, respectively. AKBA was subjected to various stress conditions: acid and alkali hydrolysis, oxidation, photodegradation, and dry and wet heat treatment. The degradation products were separated from the pure drug with significantly different hRf values.

J. Chromatogr. A 1218 (19), 2745-2753 (2011). HPTLC of sucralose in waste water on silica gel with isopropyl acetate – methanol – water 15:3:1. The developing time was 15 min. Detection with p-aminobenzoic acid reagent. Quantification by absorbance measurement at 400 nm. The limit of quantification was 100 ng/L at a recovery rate of 80 % and the extraction of a 0.5 L water sample. An interlaboratory trial in 2008 showed good agreement of the sucralose content determined in four water samples by HPTLC and other methods (HPLC–MS/MS or HPLC–TOF-MS). The good accuracy and high sample throughput capacity proved HPTLC as a well suited method for quantification of sucralose in various aqueous matrices.

J. Planar Chromatogr. 24, 160-165 (2011). HPTLC of venlafaxine hydrochloride in bulk and formulations on silica gel with butanol - acetic acid - water 3:1:1. Quantitative determination by densitometry in absorbance mode at 284 nm. The hRf value was 58. Linearity was between 100 and 600 ng/zone. The limit of detection and quantification was 39 and 131 ng/zone, respectively. The repeatability and the intermediate precision (%RSD, n = 6), were between 0.3-0.7 % and 0.6-0.9 %, respectively. The recovery was between 99.1 and 101.7 %.

J. Planar Chromatogr. 24, 412-418 (2011). HPTLC of milnacipran hydrochloride on silica gel, prewashed with methanol, with chloroform - methanol - ammonia 64:25:2 in a twin-trough chamber saturated for 20 min. Detection under UV light at 245 and 366 nm. Quantitative determination by absorbance measurement at 220 nm. The hRf value of milnacipran was 45. Linearity was between 500 and 6000 ng/zone. The method precision, intra-day precision, inter-day precision, and different analyst precision (n = 6 each, %RSD), was 1.2, 1.9, 1.6, and 1.9 %, respectively. The mean recovery (n = 3) was 99.2-99.8 % with a % RSD between 0.6-1.7 %.

J. Ethnopharmacol. 137, 1337-1344 (2011). HPTLC of phyllanthin (A) and gallic acid (B) in the whole plant of Phyllanthus simplex on silica gel with hexane - ethyl acetate 5:1 for (A) and ethyl acetate - formic acid 44:3 for (B). Detection by spraying with anisaldehyde - sulfuric acid reagent. Quantitative determination by absorbance measurement at 260 and 520 nm. The hRf values of (A) and (B) were 19 and 82, respectively. The amount found in samples was 14.5 % for (A) and 0.7 % for (B).

J. Planar Chromatogr. 24, 35-39 (2011). HPTLC of olmesartan medoxomil (OLM) and hydrochlorothiazide (HTZ) on silica gel with chloroform - methanol - formic acid 16:3:1 in a chamber saturated for 1 h. Detection under UV light at 254 nm. Quantitative determination by densitometry at 260 nm for olmesartan medoxomil and 272 nm for hydrochlorothiazide. Linearity was between 0.05-1 mg/mL. Average recovery was 100.3 % and 99.9 % for OLM and HTZ, respectively. The LOD was 138 and 137 ng/zone for OLM and HTZ, respectively, and the LOQ was 459 and 456 ng/zone for OLM and HTZ, respectively. The intra-day and inter-day precision (%RSD, n = 9) was 1.2 and 1.4 % for OLM and 1.1 and 1.3 % for HTZ.