TLC operation method

(1) Preparation of thin-layer plates Unless otherwise specified, 1 part of the stationary phase and 3 parts of water are ground and mixed in one direction in the mortar to remove air bubbles from the surface and poured into the applicator to make it stable on the glass plate. Ground coating applicator for coating (thickness: 0.2-0.3mm), remove the glass plate coated with a thin layer, dry on a water platform at room temperature, and bake at 110°C for 30 minutes, that is, desiccant The dry box is ready for use. Check the uniformity before use (can be transmitted light and reflected light inspection).

(2) Spotting Unless otherwise specified, the spotting device is used for spotting on the thin layer board, which is usually a round spot. The spotting base line is 2.0 cm away from the bottom edge. The spot diameter and the distance between the points are the same as the paper chromatography. The distance between the spots can be visually diffused so as not to affect the detection. When spotting, care must be taken not to damage the surface of the thin layer.

(3) Unfolding the expansion cylinder If it needs to be saturated with the developing agent in advance, add a sufficient amount of developing solvent to the cylinder, and attach two pieces of filter paper strip with the same height and width as the cylinder, one end is immersed in the developing agent, and the sealing cylinder The top cover allows the system to be balanced or operate as specified in the text.

Place the thin layer plate with good sample into the developing agent of the developing cylinder, immersed in the developing agent at a depth of 0.5-1.0 cm from the bottom edge of the thin layer plate (do not immerse the sample point in the developing agent), seal the cylinder head, wait until Expand to the specified distance (usually 10 ~ 15cm), remove the thin plate, dry, according to the provisions of the test under the various species.

(4) Thin layer scanning can be used if a thin layer scanner is used to scan the chromatographic spots or directly on the thin layer for scanning quantification.

The method of thin-layer scanning, unless otherwise specified, may be based on the structural characteristics and application instructions of various thin-layer scanners, and in combination with the specific circumstances, the absorption or fluorescence method may be selected to scan with dual-wavelength or single-wavelength. Since there are many factors affecting the results of thin-layer scans, it should be ensured that the test article's spot is linear within a certain concentration range, and the test article and the reference substance are scanned on the same thin layer for comparison. Calculate quantification to reduce errors. For various samples, only thin-layer chromatography with good resolution and reproducibility can produce satisfactory results.

After the elution of the spots, the thin layer was developed, and the spotted adsorbent was captured with a spatula or a trap, and then eluted with an appropriate organic solvent. The content was then measured with visible, ultraviolet spectrophotometry, and spectrofluorometry.

However, the sample spot can not be sprayed with the coloring agent, so as not to affect the determination of the spot position.

The sample emits fluorescence under ultraviolet light. The spot can be observed under the UV lamp and the spot can be removed with a needle.

The color was developed with iodine vapor and brown spots were detected in the components (volatilization after iodine adsorption).

With the standard control, when the standard point is measured on the edge, the sample is covered and the spot position is determined.

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