J. Liq. Chromatogr. Relat. Technol. 30, 2329-2335 (2007). HPTLC of sterols and fatty acids on silica gel (prewashed with methanol) with petroleum ether (36-60 °C) - diethyl ether - acetic acid 80:20:1 in a twin-trough chamber with chamber saturation. Detection by spraying with a 5 % ethanolic phosphomolybdic acid solution followed by heating at 110 °C for 10 min. Quantitative determination by absorbance measurement in the visible range.

Acta Chromatographica 6, 7-14 (1996). HPTLC of fructose, glucose and sucrose on a channeled silica gel plate with concentration zone with acetonitrile - water 17:3 for three times (freshly prepared each time, taking 15 min per run) with chamber saturation for 10-15 min. Before, just the silica gel layer was impregnated by spraying with 0.10 M sodium bisulfate solution, and subsequently with citrate buffer (1:10 dilution of citrate buffer with water, pH 4.8), each followed by drying. Detection by spraying with 1-naphthol-sulfuric acid reagent, followed by heating at 100-110 °C for 5-10 min. Quantitative determination by absorbance measurement at 515 nm. The hRf values of fructose, glucose and sucrose were 47, 43, and 28, respectively, and selectivity regarding matrix was given. No zones other than the sugars were detected in sample chromatograms because of the selectivity of the detection reagent and the retention of the beverage components in the preadsorbent. Correlation coefficients (r) for linear regression of the calibration curves typically ranged from 0.90-0.99, with an average of 0.97. The precision in matrix was 2.5 % (n = 5). The mean reproducibility of the twofold sample analyses was 4 %, ranged between 0.45 % and 7.5 %. The accuracy of the method was 94.6 %, 97.0 % and 90.8 % for sucrose, glucose and fructose, respectively. Sugar concentrations in the samples ranged from 18.4-34.3 mg/mL.

J. Planar Chromatogr. 22, 363-366 (2009). HPTLC of 5-hydroxymethylfurfural in seven Turkish fruit wines and three Turkish vinegars on silca gel with toluene - ethyl acetate - 90 % formic acid 6:3:1 in a twin trough chamber saturated for 20 min. Quantitative determination by absorbance measurement at 286 nm. The limit of detection and quantification was 0.05 and 0.13 ng/mL, respectively.

J. Braz. Chem. Soc. 21, 441-446 (2010). HPTLC of ochratoxin A in wine on silica gel with toluene - ethyl acetate - chloroform - formic acid 6:3:1. Quantitative determination by absorbance measurement at 366 nm, using a CCD camera followed by images processing using the software ImageJ. Linearity was between 0.8 and 32 µg/L. The intra-day and inter-day precisions had a RSD lower than 9.9 % and 11.5 %, respectively. LOD was 16 ng/zone while LOQ was 100 ng/zone. The proposed method is a simple, efficient and low cost tool for quantitative analysis of ochratoxin A in wine samples.

J. Liq. Chromatogr. Relat. Technol. 33, 972-979 (2010). TLC of vitamin B12 on silica gel with 2-propanol - 28 % ammonia - water 7:1:2 and 1-butanol - 2-propanol - water 10:7:10 in the dark at room temperature. After drying, agar containing basal medium and pre-cultured E. coli 215 was overlaid and then incubated at 30 °C for 20 h. Detection by spraying with a methanolic solution of 2,3,5-triphenyltetrazolium salt, B12 compounds appeared as red zones indicating E. coli growth.

J. Planar Chromatogr. 24, 320-324 (2011). TLC of a red wine sample and gallic acid, caffeic acid, chlorogenic acid, p-coumaric acid, and quercetin as standards on silica gel with toluene - ethyl actate - formic acid 6:5:1 with chamber saturation for 1 h. Detection by treatment with 1 % methanolic diphenylborinic acid 2-aminoethyl ester (natural products reagent) followed by 5 % ethanolic polyethylene glycol. Evaluation under UV light at 254 and 366 nm. Also spraying with 0.04 % methanolic DPPH radical reagent. The hRf value was 65, 60, 56, 47, and 7 for p-coumaric acid, quercetin, caffeic acid, gallic acid, and chlorogenic acid, respectively.

J. AOAC Int. 95, 1371-1377 (2012). HPTLC of organophosphate and carbamate pesticides such as chlorpyrifos (1), paraoxon (2), parathion (3) and pirimicarb (4) in fresh fruits and vegetables on silica gel in an automatic development chamber with methanol – dichloromethane 1:9 and n-hexane – ethyl acetate - dichlormethane 13:4:3. Matrix interferences were visualized at 366 nm after dipping in primuline reagent (0.5 g/L in acetone – water 4:1). Detection by immersion in a solution of rabbit liver esterase or cutinase, followed by horizontal incubation for 30 min at 37 °C. The enzymatic reaction was stopped by heating the plate at 50 °C for 5-7 min. Staining was performed with a mixture of 60 mL Fast Blue Salt B (2.5 g/L in water) and 30 mL alpha-naphythyl acetate (2.5 g/L in ethanol). Recoveries were in the ranges of 86-109, 95-129, 96-114 and 90-111 % for pesticides (1) to (4), respectively. Mean %RSD was 8.5 for all samples.

CBS 109, 10-12 (2012). HPTLC of steviol glycosides (stevioside, rebaudioside, dulcoside A, steviolbioside) on silica gel (pre-washed with methanol and dried at 100 °C for 15 min) with ethyl acetate - methanol - acetic acid 3:1:1 over 60 mm. Detection under white light after immersion in ß-naphthol reagent (2 g in 180 mL ethanol with 12 mL 50 % sulfuric acid) and heating at 120 °C for 5 min. Quantitative absorption measurement at 500 nm after derivatization. LOD was 10 ng/band and LOQ 30 ng/zone. Using the calibration curve method the LOQ was reduced to 12 ng/band via peak height and 20 ng/band via peak area. The calculated expected tolerance range over the whole procedure inclusive sample preparation considered recovery rates at 3 different concentration levels (0.02, 0.13, and 0.20 %) in milk-based matrix. The accuracy (recovery tolerance limit of 92-120 %), repeatability (3.1-5.4 %) and intermediate precision (4.0-8.4 %) were highly satisfying, exemplarily shown for stevioside in milk-based matrix. ANOVA was successfully passed to prove the working range. With the newly developed and validated HPTLC method, steviol glycosides in Stevia leaves, Stevia formulations, and food products were investigated.