Ninhydrin solution

Then remove the strip and dry it in a stream of cold air, either from a blower, or by pinning it to the lower edge of a fume-cupboard window having a vigorous draught already in operation. Then spray the strip lightly but uniformly with the ninhydrin solution (D) in a fume-cupboard, and dry as before. 

Smith [203] has described a special procedure for distilling reagents homogeneously onto a TLC plate. Ripphahn [179] later started with a TLC plate that had been dipped into ninhydrin solution, laid a 0.1 mm thick terephthalate... 

Pregnalatto and Sabino200 incorporated glycerine into the ninhydrin solution and reported an improved sensitivity and reproducibility enabling neomycin concentrations as low as 4 yg/ml to be determined. An automated ninhydrin assay has been described by Kaptionak, Biernacka and Pazdera O based on a modified Moore and Stein methodl l. 

After 2 to 3 h (the longer the better), remove the paper, quickly mark the solvent front with a pencil, and hang the paper in a fume hood to dry. After drying for 5 to 10 min, spray the developed portion with ninhydrin solution (0.1% ninhydrin in butanol or isopropyl alcohol). Allow to dry for 10 min. Then place it in a drying oven at 100°C for 5 min. Amino acid spots will be violet to blue in color. 

Materials Required Silica gel-G mobile-phase (glacial acetic acid water butan-l-ol 20 20 20 60) 100 ml solution (1) dissolve 0.1 g of sample in 5 ml of 2 M ammonia solution (2) dilute 1 ml of soln. (1) to 50 ml with water solution (3) dilute 5 ml of solution (2) to 20 ml with water Solution (4) dissolve 10 mg of glutamic acid EPCRS in sufficient water to produce 50 ml solution (5) dissolve 10 mg of glutamic acid EPCRS and 10 mg of aspartic acid EPCRS in sufficient water to produce 25 ml ninhydrin solution (0.2% w/v solution of ninhydrin in a mixture of 95 vols. of butan-l-ol and 5 vols of 2 M acetic acid ) 50 ml ... 

Procedure Apply separately to the silica gel G coated plates 5 pi of each of sols (1), (2), (3), (4) and (5) and dry the TLC plates in a current of air for 15 minutes before commencing development. Carry out the development using the above mentioned mobile-phase as usual. After removal of the plate, allow it to dry in air, spray with ninhydrin solution and heat at 100° to 105 °C for 15 minutes. 

Reduced ninhydrin in solution tends to be unstable, therefore all kinds of precautions have to be taken, such as storage in the cold, in the dark, with a reducing agent added, and exclusion of oxygen. The condition of the ninhydrin solution has to be checked at regular intervals by running an aqueous amino acid standard mixture (Sigma) and adjustment of the response factors. 

When the developing solvent reaches a few centimeters from the top of the chromatogram, remove the paper from the jar and allow it to dry in a hood. Remove the staples and spray the paper lightly with ninhydrin solution. Allow it to dry in a hood for 10 minutes. The color may be developed by placing the chromatogram in an oven (100°C for 10 min) or at room temperature for 1 to 2 hours. All the spots should be circled with a pencil, as they will fade with time. Describe in your notebook the color of each spot. 

Ninhydrin A ninhydrin solution (0.3% in acidified 1-butanol or 0.2% in ethanol) is sprayed on the plate, which is then heated (110°C). The resulting spots are stabilized by spraying with a solution made of 1 ml of saturated aqueous cupric nitrate, 0.2 ml of 10% nitric acid, and 100 ml of 95% ethanol, to yield red spots when exposed to ammonium hydroxide (25%). 

Ninhydrin solution 0.35 g ninhydrin 4 ml 96% acetic acid 100 ml butanol. 

Amino Group Content. The relative amino group concentrations measured on fabric Lots 1 and 2 are listed in Table II and are shown in Figure 4. These data include measurements made on ninhydrin solutions containing 10, 20, and 30 mg of ground fiber. 

Table II. Absorbance of Ninhydrin Solution Obtained from Silk Fabrics After...

Figure 4. Absorbance of ninhydrin solution obtained from fabric 605 (Lots 1 and 2) after heating at 150 °C as a function of fiber concentration. Key open symbols, Lot 1 filled symbols, Lot 2.

Figure 7. Absorbance of ninhydrin solution obtained from fabric 605 (Lot 2) as a function of irradiation time.

Table IV. Absorbance of the Ninhydrin Solution Obtained from Treated and Untreated Silk Fabric Lot 2 After Heating...

Absorbance of ninhydrin solution silk fabrics after heating, 120-22,125 silk fabrics exposed to light, 123-24 Accelerated aging of cellulosic textiles, effect of... 

Ninhydrin solution 160 mg of ninhydrin are dissolved in 3 ml of ethylene glycol monomethyl ether plus 1 ml of 4 M acetate buffer, pH 6.5. 

Hyanek and Cafourkova (H23) have published a simple procedure for detecting an increase in the -amino acid content of urine samples. A piece of filter paper is moistened with a 3% KOH solution, a drop of resin-treated urine (morning sample) is added and the paper is dried at room temperature. The paper is then dipped into a ninhydrin solution (15 mg ninhydrin is dissolved in 5 ml 96% ethanol and then mixed with 5 ml ethylene glycol and 0.1 ml acetic acid) and heated at 100° for 5 minutes. The intensity of the spot is compared to that of a normal urine and/or with standards of 2, 5, 10, 20, and 50 mg of glycine N per milliliter. If a positive result (>10 mg/ml) is obtained, then a quantitative determination is performed as described in Section 4.4. 

Ninhydrin, 0.2% (w/v), is dissolved in ethanol and stored in a refrigerator. Just prior to use, 0.5 ml of 2,4,6-collidine is added to each 50 ml of the ninhydrin solution. Color development can be hastened by heating the dipped plate with a warm air gun. This reagent gives distinctive colors for a large number of amino acids (Table 2). 

A 700 mmol/L hydrochloric acid (250 fiL) and distilled water (500 fiL) are added to 250 /iL sample solution. Furthermore, 2mL of 15 nunol/L ninhydrin solution and 1 mol/L sodium hydroxide solution are added to sample solution. After mixing of the solution, it is left for 7 min under dark, and fluorescence measurement (Ex. 302 nm, Em. 500 nm) was performed. 

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