P-nitrobenzenediazonium Fluoroborate Research Articles

Thin-layer chromatographic detection of carbosulfan by 4-aminoantipyrine reagent

Carbosulfan [2,3-dihydro-2,2-dimethy1-7 benzofuranyl {(dibutylamino) thio} methyl carbamate] is a carbamate pesticide, which is largely used against a variety of pests on cereal, fruits, and vegetables crops. Easy availability and low price of carbamate pesticides, particularly carbaryl, propoxur, methomyl, carbofuran, and carbosulfan, have resulted in their misuse as poison in India, and large number of cases related to their poisoning are received in Forensic Science Laboratories across the country. Therefore, their detection and identification are important in frequently encountered forensic samples. Various chromogenic reagents have been described for the detection and identification of carbamate pesticides by thinlayer chromatography. These include diazophenol after alkaline hydrolysis [1], Tollen’s reagent [2], alkaline fast blue-B [3], p-nitrobenzene diazonium fluoroborate [4], zinc chloride– diphenylamine [5], diazotized p-nitroaniline and diazotized p-aminoacetophenone [6], phenylhydrazine hydrochloride in alkaline media [7], ceric ammonium nitrate [8], diphenylamine–formaldehyde [9], and zinc (II) hexacyanoferrate (III) [10]. But the majority of above reagents are mainly meant for the detection of carbaryl and propoxur. No reference was found for the thin-layer chromatographic detection of sulfur-containing carbamate, namely carbosulfan, in the literature surveyed. However, high-performance liquid chromatography (HPLC) [11], gas chromatography (GC) [12], gas chromatography–mass spectrometry (GC–MS) [13], and spectrophotometric methods [14] are reported for determination of carbosulfan, but these are not good for initial screening of complex forensic samples. This study describes alkaline hydrolysis of carbosulfan followed by spray of 4-aminoantipyrine and potassium hexacyanoferrate (III) on thin-layer chromatographic (TLC) plate, producing redcolored spot at its R F value. 2 Experimental

High-performance liquid chromatography determination of ketone bodies in human plasma by precolumn derivatization with p-nitrobenzene diazonium fluoroborate

We developed and validated a sensitive and convenient high-performance liquid chromatography (HPLC) method for the specific determination of ketone bodies (acetoacetate and d-3-hydroxybutyrate) in human plasma. p-Nitrobenzene diazonium fluoroborate (diazo reagent) was used as a precolumn derivatization agent, and 3-(2-hydroxyphenyl) propionic acid was used as an internal standard. After the reaction, excess diazo reagent and plasma proteins were removed by passing through a solid-phase cartridge (C 18). The derivatives retained on the cartridge were eluted with methanol, introduced into the HPLC system, and then detected with UV at 380 nm. A calibration curve for acetoacetate standard solution with a 20-μl injection volume showed good linearity in the range of 1 to 400 μM with a 0.9997 correlation coefficient. For the determination of d-3-hydroxybutyrate, it was converted to acetoacetate before reaction with the diazo reagent by an enzymatic coupling method using d-3-hydroxybutyrate dehydrogenase and lactate dehydrogenase. A calibration curve for d-3-hydroxybutyrate standard solution also showed good linearity in the range of 1.5 to 2000 μM with a 0.9988 correlation coefficient. Analytical recoveries of acetoacetate and d-3-hydroxybutyrate in human plasma were satisfactory. The method was successfully applied to samples from diabetic patients, and results were consistent with those obtained using the thio-NAD enzymatic cycling method used in clinical laboratories.

Application of a Micro Multiphase Laminar Flow on a Microchip for Extraction and Determination of Derivatized Carbamate Pesticides

Determination of carbamate pesticides such as carbaryl, carbofuran, propoxur and bendiocarb was demonstrated on a microchip with newly designed microchannels developed for efficient solvent extraction. The pesticides were hydrolyzed to corresponding naphthols, coupled with p-nitrobenzenediazonium fluoroborate reagent, and then extracted into 1-butanol as colored azo derivatives and detected with a thermal lens microscope. Optimum flow rates for the aqueous and organic phases were evaluated in the continuous-flow chemical process established in the microchip. The calibration lines showed good linearity in the range of concentrations of 0.03 - 3 ppm (10(-7) - 10(-5) M) and a mass detection limit down to a nanogram level was achieved that is at least two orders of magnitude lower than the LODs for conventional spectrophotometric methods. Azo derivatives of the pesticides were successfully separated and identified by micellar electrokinetic chromatography (MEKC) using a sample prepared on a bulk scale.

Synthesis and structural characterization of a new polysiloxane with second-order nonlinear optical effect

A new polysiloxane (P2), with a high density of the indole-based chromophore and carbazolyl side groups, was prepared. Thus a polysiloxane (P1), with indole and carbazolyl groups as side chains, was first synthesized through a hydrosilylation reaction, and then the post-azo coupling of p-nitrobenzenediazonium fluoroborate toward the indole ring gave the mulifunctional indole-based chromophore-functionalized polysiloxane (P2). Molecular structural characterization for the polymers was determined by 1H-NMR, IR, and UV–visible spectra, gel permeation chromatography, and differential scanning calorimetry. The polymers were easily soluble in common organic solvents. The poled film of P2 revealed a resonant d33 value of 27 pm/V by second-harmonic generation measurements. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 769–774, 2004

Polysilanes with NLO chromophores as pendant groups by utilizing different synthetic strategies

This paper summarizes our research on the synthesis and properties of several kinds of functionalized polysilanes (FPSs) containing nonlinear optic (NLO) chromophores in the side chain. They have been synthesized successfully through utilizing different synthetic strategies: chloromethylation of poly(methylphenylsilanes) and the following etherification with the hydroxy-containing NLO chromophore in water–chloroform two-phase system with Brij35 as a phase-transfer catalyst; hydrosilylation of polyhydrosilanes with the NLO chromophore containing the terminal double bond; etherification of chlorine-containing polysilanes with the hydroxy-containing NLO chromophore; and post-functionalization of phenyl group-containing polysilanes through azo coupling with p-nitrobenzenediazonium fluoroborate or tricyanovinylation with the oxidant tetracyanoethylene. FPSs were characterized with FT-IR, UV–vis spectra, differential scanning calorimetry (DSC), gel permeation chromatography (GPC), and elemental analysis. The second-order optical nonlinear properties of the polysilanes were determined by in situ second harmonic generation (SHG) experiments.

Second-Order Nonlinear Optical Property of Polysiloxane Containing Indole-Based Multifunctional Chromophore

A new strategy to develop polysiloxane ( P2 ) with a high density of the multifunctional indole-based chromophore is presented. Thus a polysiloxane ( P1 ) with indole as side chains was first synthesized through hydrosilylation reaction, and then the post azo coupling of p-nitrobenzenediazonium fluoroborate toward the indole ring afforded a mulifunctional indole-based chromophore-functionalized polysiloxane ( P2 ). The polymers exhibit excellent solubility in common organic solvents and are thermally stable. The poled lilm of P2 reveals a resonant d 33 value of 25 pm/V by second harmonic generation ( SHG ) measurements.

High performance liquid chromatographic determination of acetoacetate by post-column derivatization with p-nitrobenzene diazonium fluoroborate.

We have applied a color-developing reagent, p-nitrobenzene diazonium fluoroborate (diazo reagent) as a post-column derivatization tool for the specific determination of acetoacetate (AcAc) in high performance liquid chromatography (HPLC). A mobile phase consisting of 50 mM KH(2)PO(4), 4 mM tetra-n-butylammonium phosphate (TBAP) as an ion-pair reagent and 2 v/v% methanol, pH 3.5, diazo reagent solution with 0.2% triton X-100, and alkaline solution of 1.5 mol/l NaOH were pumped using three independent pumps. Specific color development on-line was monitored at 645 nm. A calibration curve for AcAc standard solution with an injection volume of 20 microl showed a good linearity in the range 0.01-2.5 mM with a correlation coefficient of 0.999. For the determination of 3-hydroxybutyrate (3-HOBA), 3-HOBA was converted to AcAc by an enzymatic-coupling method using 3-HOBA dehydrogenase and lactate dehydrogenase. Analytical recoveries of AcAc and 3-HOBA added to serum and urine were satisfactory.

Flow-injection determination of paraoxon by inhibition of immobilized acetylcholinesterase

Two flow-injection methods (continuous-flow and stopped-flow) are proposed for the determination of paraoxon, applying the dual-injection technique and spectrophotometric detection. They are based on the inhibition of the acetylcholinesterase-catalysed hydrolysis of α-naphthyl acetate and subsequent reaction of the α-naphthol produced with p-nitrobenzenediazonium fluoroborate. For the continuous-flow system the calibration graph was linear from 5 × 10 −7 to 1.5 × 10 −5 M, the relative standard deviation (r.s.d.) ( n=6) for an 8 × 10 −6 M standard was 1.4%, the limit of detection (3σ) was 4 × 10 −7 M and the sample throughput was ca. 60 h −1. For the stopped-flow system the linear range was from 1 × 10 −8 to 4 × 10 −7 M, the r.s.d. for a 2.5 × 10 −7 M standard was 0.9%, the limit of detection was 8 × 10 −9 M and the sample throughput was 30 h −1.

ChemInform Abstract: Electrophilic Substitution in Indoles. Part 14. Azo‐Coupling of Indoles with p‐Nitrobenzenediazonium Fluoroborate.

ChemInformVolume 19, Issue 4 Heterocyclic Compounds ChemInform Abstract: Electrophilic Substitution in Indoles. Part 14. Azo-Coupling of Indoles with p-Nitrobenzenediazonium Fluoroborate. A. H. JACKSON, A. H. JACKSON Dep. Chem., Univ. Coll., Cardiff CF1 1XL, UKSearch for more papers by this authorP. P. LYNCH, P. P. LYNCH Dep. Chem., Univ. Coll., Cardiff CF1 1XL, UKSearch for more papers by this author A. H. JACKSON, A. H. JACKSON Dep. Chem., Univ. Coll., Cardiff CF1 1XL, UKSearch for more papers by this authorP. P. LYNCH, P. P. LYNCH Dep. Chem., Univ. Coll., Cardiff CF1 1XL, UKSearch for more papers by this author First published: January 26, 1988 https://doi.org/10.1002/chin.198804193Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume19, Issue4January 26, 1988 RelatedInformation

Electrophilic substitution in indoles. Part 15. The reaction between methylenedi-indoles and p-nitrobenzenediazonium fluoroborate

p-Nitrobenzenediazonium fluoroborate (2 mol equiv.) reacts under aqueous conditions with 3,3′methylenedi-indole (9a) and N,N-dimethyl-3,3′-methylenedi-indole (9c) to give, in each instance, high yields of the corresponding 3-p-nitrophenylazoindoles (13a) and (13c). When 1 mol equiv. of diazonium salt is used, the methylenedi-indole (9a) gives < 1 mol equiv. of the 3-(p-nitrophenylazo)indole (13a) and some methylenedi-indole is recovered. In dry acetonitrile, 3,3′methylenedi-indole gives, with 1 mol equiv. of diazonium salt, a mixture of 3-(p-nitrophenylazo)indole (13a)(0.45 mol equiv.) and the unstable 3-(p-nitrophenylazo)-2,3′-methylenedi-indole (16a)(0.42 mol equiv.). The latter was also synthesized from indole-2,3-dione and chloroacetylindole via indol-2-yl, indol-3-yl, and 2,3′methylenedi-indole. Essentially similar results were obtained with N,N-dimethyl-3,3′-methylenedi-indole (9c) and the diazonium salt. The unsymmetrical compounds 3-indol-3-ylmethyl-1,2-dimethylindole (9d) and 3-indol-3-ylmethyl-2-methylindole (9e), with 2 mol equiv: of diazonium salt in aqueous solution, each give high yields of the two possible 3-p-nitrophenylazoindoles. With 1 mol equiv. of the diazonium salt only the 2-methyl-3-p-nitrophenylazo derivatives are obtained, together with 3,3′methylenedi-indole. In dry acetonitrile, with either 1 or 2 mol equiv. of diazonium salt, the unsymmetrical methylenedi-indoles each give only the 2-methyl-3-p-nitrophenylazoindoles. The displacement of an indolylmethyl residue from methylenedi-indoles by the diazonium salt, and the formation of the azo coupled rearrangement product (16a) provides firm evidence that azo coupling of 3-alkylindoles to give the 2,3-disubstituted indoles proceeds by initial attack at the 3-position followed by rearrangement, rather than by direct substitution at the 2-position.

Thin -layer Chromatographic Separation and Identification of Carbofuran and Two Carbamate Metabolites and their Dinitrophenyl Ethers

Abstract Residues of carbofuran and its 2 carbamate metabolites in fortified fresh water, a sandy loam soil, and plant tissues were extracted with HCl, partitioned into methylene chloride and cleaned up on deactivated Florisil. Aliquots of extracts were chromato-graphed on silica gel G and GF plates and carbofuran, 3-hydroxycarbofuran, and 3-ketocarbofuran were hydrolysed into their 7-phenols with KOH spray. Spots were visualized with either p-nitrobenzenediazonium fluoroborate or 2,6-dibromobenzo-quinone-4-chloroimine. The characteristic color of spots before and after spraying with KOH or with either of the chromogenic reagents in ordinary light and under UV light helped in identification and differentiation of the compounds. As low as 0.05ppm in water and 0.2ppm in soil or strawberry, lettuce, carrots, peas and potatoes could be detected. 3-Hydroxycarbofuran in the remaining extracts was converted into 3-ethoxycarbofuran and the compounds were converted into their dinitrophenols and chromatographed on silica gel GF. Good separation of compounds was obtained but the limit of detection was 0.1 ppm in water and 0.3 ppm in soil and plant tissues. The procedures were applicable to field-treated rutabaga samples and useful in identity confirmation.

Sensitive and simplified method for the differential determination of serum levels of ketone bodies

A highly sensitive and simplified method for the differential determination of serum ketone bodies has been developed. Serum was deproteinized with perchloric acid, and acetoacetate contained in the supernate was reacted with newly syntheized p-nitrobenzene diazonium fluoroborate at 37°C for 10 min. The formed hydrazo compound was converted by alkali to the more stable azo compound which has a peak absorbance at 645 nm. For the determination of 3-hydroxybutyrate, this was enzymatically converted to acetoacetate using 3-hydroxybutyrate dehydrogenase, LDH, NAD and pyruvate. Using 0.2 ml serum, acetoacetate and 3-hydroxybutyrate could be quantitated in 30 min. The described method is five times more sensitive than the enzymatic photometric method and can detect individual ketone bodies at concentrations as low as 20 μmol/l. Differential determination of serum levels of ketone bodies is clinically useful for the diagnosis of type 1 diabetes and in monitoring diabetic control.

Colorimetric determination of dimethoate or omethoate

A simple, sensitive and rapid colorimetric method is described for determining dimethoate [ O,O-dimethyl- S-( N-methylcarbanoylmethyl)phosphorodithioate] and omethoate by an enzymatic method using pig liver acetone powder as enzyme source and p-nitrobenzenediazonium fluoroborate as the chromogenic reagent. This colorimetric method is more sensitive than non-enzymatic methods. Inhibition can be detected at ng levels and amounts ranging from 50 to 1000 ng of omethoate and from 1 to 10 μg of dimethoate can be estimated.

Colorimetric Determination of Methyl Parathion and Oxygen Analog

A simple, sensitive, and rapid colorimetric method is described for determining methyl parathion (O,O-dimethyl-O-p-nitrophenyl phosphorothioate) and methyl paraoxon (O,O-dimethyl-O-p-nitrophenyl phosphate), using p-nitrobenzene diazonium fluoroborate as the chromogenic salt. This colorimetric method is more sensitive than are other colorimetric methods based on non-enzymatic reactions. Pig liver acetone powder cholinesterase was found to be sensitive to methyl parathion. Inhibition can be detected at picogram levels, and 50-80 ng methyl paraoxon and 1-9 micrograms methyl parathion can be estimated.

Thin Layer Chromatography of Parathion as Paraoxon with Cholinesterase Inhibition Detection

A simple, sensitive, and rapid method is described for the quantitative estimation of ng amounts of parathion (O,O-diethyl O-p-nitrophenyl phosphorothioate) as paraoxon (O,O-diethyl O-p-nitrophenyl phosphate) on thin layer chromatograms. Paraoxon is detected by inhibition, using p-nitrobenzenediazonium fluoroborate as the chromogenic reagent. This chromogenic reagent is more sensitive than Fast Blue B or indoxyl acetate; 0.1 ng may be detected and amounts from 5 to 50 ng may be estimated. The method is a viable alternative to gas chromatographic analysis for parathion.

Studies of heterocyclic compounds. Part XX. Substitution of 1-oxa-6,-6a-dithiapentalenes with arenediazonium fluoroborates: rearrangement into 6,6a-dithia-1,2-diazapentalenes

1-Oxa-6,6a-dithiapentalenes unsubstituted at position 3 couple with arenediazonium fluoroborates with accompanying rearrangement. 1-Oxa-6,6a-dithiapentalene and its 5-t-butyl and 5-phenyl derivatives gave 1-aryl-3-formyl-6,6a-dithia-1,2-diazapentalenes and the corresponding 5-substituted analogues, respectively. 1-Oxa-6,6a-dithiapentalenes in which the reactive position 3 is blocked, couple with p-nitrobenzenediazonium fluoroborate with accompanying deformylation. 3,4-Dimethyl- and 3-methyl-5-phenyl-1-oxa-6,6a-dithiapentalene gave 3,4-dimethyl-1-p-nitrophenyl- and 3-methyl-1-p-nitrophenyl-5-phenyl-6,6a-dithia-1,2-diazapentalene, respectively, and 4,5-dihydro-3H-1-oxa-7,7a-dithiacyclopent[cd]indene gave 6,7-dihydro-2-p-nitrophenyl-5H-2a,3-dithia-1,2-diazacyclopent[cd]indene. 4,5,6,7-Tetrahydro-2-t-butyl-8-oxa-1,8a-dithia-cyclopent[a]indene reacted with p-nitrobenzenediazonium fluoroborate (i) in acetonitrile to give 5-(1-p-nitro-phenyl-5-t-butyl-6,6a-dithia-1,2-diazapentalen-3-yl)pentanoic acid, and (ii) in methanol to give methyl 5-(1–p-nitrophenyl-5-t-butyl-6,6a-dithia-1,2-diazapentalen-3-yl)pentanoate. These results are accounted for by a previously proposed mechanism of electrophillic substitution of 1-oxa-6,6a-dithiapentalenes and related heterocyclic systems.

Interactions of p-nitrobenzene diazonium fluoroborate and analogs with the active sites of acetylcholine-receptor and -esterase.

p-Nitrobenzene diazonium fluoroborate (NDF) is a potent inhibitor of the carbamylcholine-induced depolarization of the electroplax and of acetylcholinesterase. It probably forms covalent bonds with the acetylcholine-receptor and -esterase at the active site of the proteins. Its inhibitory strength is at least the same as that of trimethylammonium diazonium fluoroborate (TDF). The p-acetoxy analog, with its weaker electron-withdrawing group, is about ten times weaker as an inhibitor than the trimethylammonium or p-nitro analogs, both of which have strong electron-withdrawing groups. After treatment of the electroplax preparation with dithiothreitol, NDF remains an irreversible receptor-inhibitor, while TDF becomes a potent reversible receptor-activator. TDF is self-inhibitory: applied before reduction, it no longer depolarizes. Although the first observations on TDF suggested that the compound labels both proteins by virtue of the steric complementary of its trimethylammonium group to a negative subsite in the proteins, the present study indicates that it is the positively charged diazonium group that reacts with the active sites of the proteins to form a covalent bond with an appropriate amino-acid residue.

Analysis of Phenols (III)

The color reactions of 75 samples of of phenols with p-nitrobenzenediazonium fluoroborate in alkaline methanolic solution were studied spectrophotometrically (see Table 1, 2, 3 and 4). The wavelengths at maximum absorption were ranged from 445 to 616mμ.The coloring matters formed by the color reactions between 8 samples of phenols and p-nitrobenzenediazonium fluoroborate were separated on Silica gel plate. The Rf values of the coloring matters were shown in Table 5.