J. Planar Chromatogr. 19, 348-354 (2006). HPTLC of puerarin, daidzein, daidzin, and 3’-methoxypuerarin on silica gel, pre-washed with methanol, in an unsaturated twin-trough chamber with chloroform - methanol - ethyl acetate - water 16.2:18.8:52:3. Quantitative determination by absorbance measurement at 254 nm. The relative standard deviation of Rf values, retention times and peak area percentages all meet the national standards.

J. Planar Chromatogr. 27, 29-32 (2014). HPTLC of rhein in the pulp of Cassia fistula on silica gel with ethyl acetate - methanol - water 100:17:10. Quantitative determination (1) by TLC image analysis using a flatbet scanner and (2) by absorbance measurement at 435 nm. The hRF value for rhein was 49. Linearity was in the range of 400-1200 ng/zone for (1) and 29-230 ng/zone for (2). The intermediate/interday/intra-day precisions were below 3 % (n=3). The LOD and LOQ for rhein were 85 and 257 ng/zone for (1) and 3 and 11 ng/zone for (2). Mean recovery was 102.3 % for (1) and 101.2 % for (2).

Chem.(BUNSEKI KAGAKU) 34, 346-350 (1985). (Japanese) (Improvement of scanning photoacoustic densitometer for thin-layer chromatography and determination of squalene in human skin surface lipid). Photoacoustic densitometer with a lock-in amplifier with a reference frequency of 80 Hz and a band pass filter of 3 Hz. Detection limits (S/N = 2) of squalene and Sudan Red 7B were 50 ng and 35 ng, resp. Relative SD, 3.7 % for squalene (860 ng) and 3.3 % for Sudan Red 7B (194 ng). Method applied on content of squalene in the human skin surface lipid.

(Japanese). Proc. Hoshi Coll. Pharm. 28, 51-57 (1986) (Hoshi Yakka Daigaku Kiyo). Description of a light scanning photoacoustic densitometer for determination of organic compounds separated on TLC plate with application examples. Discussion of the use of light emitting diode and laser diode as the light source.

Anal. Letters 22, 507-518 (1989). Demonstration of a voltammetric detector coupled with thin-layer chromatography for the quantification of trace organic compounds on the plate. Detection limits for p-anisidine and p-phenetidine, about 10 ng. Linearity, 2 orders of magnitude.

J. Pharm. Biomed. Anal. 8, 253-257 (1990). A densitometric method for determination of complex mixtures of conjugated oestrogens in raw material and tablets was developed. The proposed procedure comprised hydrolysis of sodium sulfate esters of oestrogens and oestradiol, equilenin, 17a-dihydroequilenin, the chloroform extraction of free oestrogens and methyltestosterone (internal standard). TLC on silica with chloroform - cyclohexane - dioxane - triethylamine 45:40:10:6. Quantification by densitometry at 254 and 280 nm. Detection limit 0.06 µg, recoveries 97,1% (conjugated oestrogens) and 103,2% (tablets). The proposed method is simple, rapid, and reproducible.

Amer. Lab. 25, 24 I-M (1993). Description of video densitometer with a few examples, involving electronic record-keeping, micro focus lens, and system versatility.

Chinese J. Chromatogr. (Sepu) 15, 310-313 (1997). Discussion of the coherent features and the important analytical performance parameters such as accuracy, precision, reproducibility, specificity, detection and quantification limits, linearity and range, etc. in TLC, stressing on the validation methods and the acceptance criteria for sample preparation, sample stability in solution and on plate, sample exposure time, robustness and quality of the stationary and mobile phases, sample application, chamber saturation, detection as well as quantification. It is recommended that the definition of the validation parameters and the validation procedures for quantitative TLC should be given whenever results are reported.