Dragendorff reagent, modified

In the procedure with mobile phase 1 and 2, the visualization is accomplished by screening under uv light (254 and 366 nm) and in addition by spraying with Dragendorff s reagent, modified by Munier and Deboeuf, followed by 30 percent hydrogen peroxide. 

Polydocanol is a mixture of monoethers from dodecyl alcohol and Macrogols, which contains an average of 9 oxyethylene units and is used as a local anesthetic. As this mixture of substances is not UV active, visualization by derivatization is performed with a modified Dragendorff reagent ... 

Figure 87. Identification of metoclopramide base and polidocanol in a suppository mass after dipping in a modified Dragendorff reagent...

The bismuth active substances (BiAS) method for the determination of nonionic surfactants with barium tetraiodobismuthate (BaBil4, modified Dragendorff reagent) is used in the standardized (DIN-Norm) procedure in Germany, as well as in other countries. Ba as a hard Lewis acid forms cationic coordination complexes with the polyethoxylate chain of the nonionic surfactants, which are precipitated by [Bim in the presence of acetic acid. The orange precipitate is then dissolved with ammonium tartrate solution, and the released bismuth ions are determined by potentiometric titration with pyrrolidinedithiocarbamate solution. Waters et al. optimized the BiAS procedure by introduction of a cation/anion exchange clean-up of the sublation extracts. The BiAS procedure fails to determine ethoxylates with less than five ethoxy units because these compounds are not precipitated by barium tetraiodobismuthate. Thus, this procedure is not suitable for determination of APEO metabolites, i.e., the shorter APEO and AP. ... 

Jia ZQ, Tian CN. Quantitative determination of polyethylene glycol with modified Dragendorff reagent method. Desalination 2009 247(l-3) 423-9. 

Detection The less volatile tar bases can be detected on fluorescent layers (e. g., silica gel GF264)- Other possibilities are using the spray reagents listed for the amines, e. g., iodine solution (Rgt. No. 144), permanganate solution (Rgt. No. 200), antimony(V) chloride (Rgt. No. 18) or the modified Dragendorff reagent for alkaloids (Rgt. No. 98). 

The separated homologues are visualised with modified Dragendorff reagent (No. 94). The jR/-values fall with increasing content of ethylene oxide units. 

Schiill, Dassel, FRO, impregnated with 0.5 m KH2PO4 Visualization diazot. sulfanil-ic acid resp. modified Dragendorff reagent... 

Silica gel G plates are used, with development by 80 20 ethyl ether/benzene. The sample is spotted as 30 or 40 pL of a 5% MeOH solution. Modified Dragendorff reagent is suitable for visualization. Residual alcohol appears as a light spot on a yellow background, with an Rf value of about 0.7. The sulfated material remains at the origin. The detection limit is about 0.1%. 

Primulin, 0.005% in EtOH, 1-s contact, or modified Dragendorff reagent, 1-s contact... 

System 1 pinacryptol yellow for anionics modified Dragendorff reagent for nonionics and cationics system 2 palatine blue Pinacryptol yellow iodine and cobalt thiocyanate used for confirmation... 

Dichlorofluorescein anisidine/K104 modified Dragendorff reagent acidic naphthoresorcinol molybdic acid Direct densitometry (254 nm), fluorescence quenching, pinacryptol yellow, rhodamine B, and iodine... 

Pinacryptol yellow, modified Dragendorff reagent, ninhydrin, iodine, leuco-malachite green, molyb-dophosphoric acid, cobalt thiocyanate, and supres-sion of fluorescence of the F-254 plates... 

Modified Dragendorff reagent forms a precipitate with even small amounts of poly-alkoxylates (45). The following procedure is applicable to amounts of nonionic down to about 0.1 mg ... 

Procedure Qualitative Test for Nonionic Surfactants Using Modified Dragendorff Reagent (45). 

Anionics from nonionics Merck Silica Gel G 10 10 5 2 PrOH/CHCl3/MeOH/ IOMNH3 Pinacryptol yellow and modified Dragendorff reagent 7... 

Unsulfated alcohol (down to about 0.1%), either from incomplete synthesis or formed by hydrolysis, may be determined in alkylsulfates by TLC on silica, since the alcohol has a high Rf value and is visible after spraying with modified Dragendorff reagent as a light spot on a yellow background (22). TLC is also suitable for detection of sultones and other thermal degradation products (23). 

Free alcohol in dodecanol sulfate detection Silica Gel G 80 20 ethyl ether/benzene Modified Dragendorff reagent 22... 

C 4-Ci8 alcohol 8-mole ethoxysulfate tributylphenol 8-mole ethoxysulfate determination of active agent, PEG, mono- and disulfated PEG, and un-sulfated material Silica gel plate (Merck No. 5715/0025) sprayed with 0.05 M oxalic acid and 2.5% ammonium sulfate solution dried at 110 - C 90 10 CHClj/MeOH Modified Dragendorff reagent or SO3 charring 88... 

Fatty alcohol ether sulfate and non-ylphenol ether sulfate separation of oligomers after hydrolysis to the corresponding nonionic compounds Silica Gel G 45 5 2.5 Ethyl acetate/ NH40H/Me0H Modified Dragendorff reagent 7... 

Ether carboxylates may be determined by TLC on silica. With a developing solvent of 80 20 chloroform/methanol, the ether carboxylate remains near the origin, while the non-carboxylated nonionic portion rises nearly to the solvent front. Carboxylated PEG has an even lower Rf than the ether carboxylate, while PEG has a somewhat lower Rf than the parent nonionic. 2,7-Dichlorofluorescein is a suitable visualization reagent. A more specific visualizer is modified Dragendorff reagent, which serves to differentiate the ether carboxylate from most other anionics, although low ethoxylates, like nonylphenol-3-mole ethoxylate, cannot be detected with useful sensitivity (29,30). As with ethoxylated non-ionics, the ethoxy chain length distribution of ether carboxylates may be determined by TLC (31). 

Since modified Dragendorff reagent is not useful for detection of compounds containing less than about 4 moles of ethylene oxide, primulin is sometimes also used to detect lower oligomers (43). 

C 2 alkyl 4-mole ethoxylate Aminopropyl-modified silica 80 20 1 toluene/n-PrOH/25% NH, Dragendorff reagent 19... 

Ci()-Ci2 alkyl 1- to 15-mole ethoxylates ethoxy distribution Merck Silica Gel 60 F-254, 0.25 mm, activated at 120-C for 15 min 80 14 10 ethyl acetate/HOAc/HzO Eosin modified Dragendorff reagent barium chloride/triio-dide solution 9... 

C12-C16 alkyl 3- to 14-mole ethoxy- Silica Gel 60 F254 2-Butanone, saturated with H2O Modified Dragendorff reagent 96... 

C)2 alkyl 9-mole ethoxylates incomplete resolution of ethoxy distribution identification and determination in pharmaceuticals Merck silica gel 150 20 2 CH2Cl2/MeOH/H20 Modified Dragendorff reagent 98... 

Cg-Cis alkyl 6-mole ethoxylates alkyl chain distribution RP-8 WF 254 S 88 12 MeOH/HzO Modified Dragendorff reagent 96... 

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