2.4.6- Trinitrobenzenesulfonic acid

Other tests for the detection of amino functionalities on solid supports include the TNBS (2,4,6-trinitrobenzenesulfonic acid, picrylsulfonic acid) [Hancock and Battersby Anal Biochem 71 260 ]976], the DABITC [Shah et al. Anal. Commun. 34 325 7997] and the NF31 [Madder et al. Eur J Org Chem 2787 7999] tests. 

TRINITROBENZENE TRINITROBENZENESULFONIC ACID TRINITROBENZOIC ACID TRINITROCHLOROBENZENE TRINITROFLUORENONE... 

Dipping solution Dissolve 100 mg 2,4,6-trinitrobenzenesulfonic acid in a mixture of 20 ml acetone, 20 ml ethanol and 10 ml water. 

On heating primary amines form colored Meissenheimer complexes with trinitrobenzenesulfonic acid. 

Trimethylaniline lb 268 Trimethyltin chloride lb 319 Trimipramine lb 352,354,355 Trinitrobenzenesulfonic acid, reagent... 

Lysine Acid anhydrides, succinimidyl esters, iso thiocyanates, trinitrobenzenesulfonic acid... 

A 0.5 M NaCl in 0.1 M borate buffer, pH 9.5 2,4,6-trinitrobenzenesulfonic acid glacial acetic acid... 

Rodriguez-Cabezaz, M. E., ]. Galvez, M. D. Lorente, et al. Dietary fiber down-regulates colonic tumor necrosis factor alpha and nitric oxide production in trinitrobenzenesulfonic acid-induced colitis rats. J Nutr 2002 132(11) 3263-3271. 

The extent of succinylation and acetylation was determined by the trinitrobenzenesulfonic acid (TNBS) method as described by Hall et al. (31) Protein (5 mg) isolated from chemically modified and control soy flour in 0.8 ml of aqueous solution was added to 1 ml of 4% NaHCOg, followed by addition of 0.2 ml of 2,4,6-trinitrobenzenesulfonic acid (12.5 mg/ml). The reaction mixture was incubated at 4O C for 2 hr, and 3.5 ml of 36% HCl was added. The tubes were stoppered and kept at 110 C for 4 hr. After cooling to room temperature (24 C), volume of solution was made up to 10 ml with distilled water, and contents were extracted twice with anhydrous diethyl ether. 

Trinitrobenzenesulfonic acid has been also used for the prechromato-graphic derivatization of aminoglycosides in alkaline media (228, 229). A major advantage of this label is the fact that hydroxyl groups cannot be concurrently derivatized, thus increasing, the selectivity. Unlike prementioned labels, 4-fluoro-... 

Trinitrobenzenesulfonic Acid(called Pikryl sulfonylsaure in Ger), (O2N)3C6H2.S03H mw 293-17, N 14.33% crysts of the trihydrate, mp-sinter ca 100° and the anhyd acid melts ca 185° sol in w, ale eth diffc sol in chlf insol in benz. Can be prepd by heating an ale soln of picryl chloride with an excess of Na sulfite. Its expl props were not investigated. The Sodium salt,... 

Trinitrobenzenesulfonic acid hydrate (TNBS) reacts with amino acids, yielding a yellow product (Fig. B2.2.3) whose absorbance is measured at 340 nm. TNBS reacts only with amino groups in their unprotonated state. TNBS binds to amino acids in two steps (1) a fast reaction with low affinity, and (2) a slow reaction with relatively high affinity. For practical purposes, the two-step reaction should be considered as one. TNBS reacts with primary amines under slightly alkaline conditions, and lowering the pH stops the reaction. 

Adler-Nissen, J. 1979. Determination of the degree of hydrolysis of food protein hydrolysates by trinitrobenzenesulfonic acid. J. Agric. Food Chem. 27 1256-1262. 

TMCS trimethylchlorosilane imidazole TMG tetramethylguanidine TMP 1,1,3,3-tetramethoxypropane TMS trimethylsilyl TNBS trinitrobenzenesulfonic acid TOCSY total correlation spectroscopy TPA texture profile analysis TPCK Af-tosyl-L-phenylalanine chloromethyl ketone... 

Cyclamate can also be determined after its oxidation to cyclohexylamine. Cyclohexy-lamine can be quantified by HPLC with trinitrobenzenesulfonic acid precolumn derivatization and UV detection (72). Cyclohexylamine can also be converted into a fluorescent derivative, separated on a Cl8 reversed-phase column with acetonitrile Na2HP04 buffer (64 36, v/v), and quantified at 350 and 440-650 nm of excitation and emission, respectively (73). 

Trinitrobenzenesulfonic acid (14.7 g., 0.050 mole) (Note 2), previously dried for at least 1 hour at 80-100° (1 mm.), is placed in flask B, which is then immersed to the level shown in Fig. 2 in a bath of acetone maintained at —35° to —40° by addition of small amounts of dry ice (Note 3). About 200 ml. of dimethyl ether is rapidly poured from an ampoule into flask B (Note 3). Flasks A and B are connected as shown in Fig. 2, and magnetic stirring is started in flask B. When most of the sulfonic acid has dissolved, gaseous dimethyl ether is introduced through C at such a rate that a rapid stream of individual bubbles passes through the diazomethane solution in flask A. In the course of the reaction all the acid goes into soution and is replaced by a fluffy precipitate of the oxonium salt. The introduction of dimethyl ether is discontinued as soon as the supernatant solution in flask B turns yellow (Notes 5 and 6). 

Trinitrobenzenesulfonic acid from Nutritional Biochemical Corp., Cleveland, Ohio, can be used without any purification other than drying. The checkers observed m.p. 174-177° for the dried acid. 

Diazomethane reacts with 2,4,6-trinitrobenzenesulfonic acid with ring opening similar to that observed with 1,3,5-trinitrobenzene.6 Hence an excess of the reagent is to be avoided. The yellow color is not due to the presence of diazomethane itself. The reaction time is highly sensitive to the temperature of the xylene solution and to the flow rate of gaseous dimethyl ether. The reaction time is usually 20-40 minutes. 

Primary aliphatic Kaiser (ninhydrin)/ c trinitrobenzenesulfonic acid (TNBSA)/... 

Alam et al. (2001) studied the inhibitory action of CNBR fragments of the RATI on amylase 2 purified from porcine pancreas and reported that the fragment comprising the first 10 amino acids of the N-terminal segment inhibited amylase competitively. NH2-Ser-Val-Gly-Thr-Ser-Cys-Ile-Pro-Gly-OH was most effective. A serine to alanine transformation diminished the inhibitory effect. Blocking the N-terminus abolished the a-amylase inhibitory activity. It may be presumed that the abolition of the a-amylase inhibitory activity with 2,4,6-trinitrobenzenesulfonic acid as observed by Shivraj and Pattabhiraman (1981) may have been due to its interaction with cysteine. Figure 6.9 shows a representation of this ragi protein with its ability to bind both a-amylase and trypsin with its two arms. 

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