Thermally assisted methylation and subsequent silylation of scheduled acids of chemical weapon convention for on-site analysis and its comparison with the other methods of methylation

Amphaisri, Kanchanavadee; Palit, Meehir; Mallard, W. Gary

doi:10.1016/j.chroma.2010.12.065

Cited by 19 publications

(13 citation statements)

References 27 publications

(35 reference statements)

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“…The parameters investigated were the excess of the derivatization reagent (which ranged from 10‐ to 200‐fold), the reaction temperature (20–60 °C) and the reaction time (5–90 min). The ranges for the parameters were selected based on values found in the literature in methods using other diazomethane‐based reagents . A three‐factor central composite face‐centered design was adopted, and a total of 17 experimental runs were performed (including a triplicate at the center point).…”

Section: Methodsmentioning

confidence: 99%

“…However, phosphonic acids are polar and non‐volatile, and therefore must be derivatized prior to GC analysis . Silylation, methylation and pentafluorobenzylation are the most widely used methods for derivatizing APAs. However, derivatization can be problematic since the derivatization process may be water sensitive, the derivatized products may be relatively unstable and purification may be required prior to analysis.…”

Section: Introductionmentioning

confidence: 99%

“…Recently, methods based on new water‐tolerant derivatizing agents have been developed to overcome some of these problems. These new reagents include trimethylsilyldiazomethane and 3,5‐bis(trifluoromethyl)‐phenyldiazomethane . The EI spectra of alkylphosphonic acid derivatives are often very similar and/or their molecular peaks are often very weak or absent.…”

Section: Introductionmentioning

confidence: 99%

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Structural determination of nerve agent markers using gas chromatography mass spectrometry after derivatization with 3‐pyridyldiazomethane

2013

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Nerve agents are a class of organophosphorous chemicals that are prohibited under the Chemical Weapons Convention. Their degradation products, phosphonic acids, are analyzed as markers of nerve agent contamination and use. Because the phosphonic acids are non-volatile and very polar, their identification by GC-MS requires a derivatization step prior to analysis. Standard derivatization methods for gas-chromatography electron-impact mass-spectrometry analysis give very similar spectra for many alkyl phosphonic acid isomers, which complicates the identification process. We present a new reagent, 3-pyridyldiazomethane, for preparing picolinyl ester derivatives of alkyl methylphosphonic acids facilitating the determination of their structure by enhancing predictable fragmentation of the O-alkyl chain. This fragmentation is directed by the nitrogen nucleus of the pyridyl moiety that abstracts hydrogen from the O-alkyl chain, inducing radical cleavage of the carbon-carbon bonds and thereby causing extensive fragmentation that can be used for detailed structure elucidation of the O-alkyl moiety. The separability of related isomers was tested by comparing the spectra of the picolinyl esters formed from twelve hexyl methylphosphonic acid isomers. Spectral library matches and principal component analysis showed that the picolinyl esters were more effectively separated than the corresponding trimethylsilyl derivatives used in the standard operating procedures. The suggested method will improve the unambiguous structural determination process for phosphonic acids.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Structural determination of nerve agent markers using gas chromatography mass spectrometry after derivatization with 3‐pyridyldiazomethane

2013

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“…220-223 C), thus requiring their prior derivatization for their analysis and detection. 6,9,10 Therefore, much interest has rapidly developed in the detection of these products due to the fact that GC/MS is a heavily preferred analytical tool over LC/MS due to its cost-efficient operation, maintenance and advanced positioning in relation to LC/MS in the development of portable and fielddeployable units. 11 Highly efficient methods exist for the derivatization of polar compounds for their subsequent analysis by GC/MS; some of the most common ones like silylation and methylation have not displayed their usually encountered success with other analytes when it comes to 3Q.…”

Section: Introductionmentioning

confidence: 99%

Trocylation of 3‐quinuclidinol, a key marker for the chemical warfare agent 3‐quinuclidinyl benzilate, for its enhanced detection at low levels in complex soil matrices by electron ionization gas chromatography–mass spectrometry

Valdez

Leif

et al. 2021

Rapid Comm Mass Spectrometry

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Rationale: Detection of 3-quinuclidinol (3Q), a marker for the chemical warfare agent 3-quinuclidinyl benzilate, is very difficult by gas chromatography-mass spectrometry (GC/MS), providing low, broad signals even when analyzed in isolated form.Therefore, a method that can convert 3Q into a substrate with enhanced detectability by GC/MS would be an important tool for its analysis.Methods: 2,2,2-Trichloroethoxycarbonyl chloride (TrocCl) was used in the derivatization of 3Q in three different soils of varying composition and total organic content (Virginia type A soil, Nebraska EPA standard soil and Ottawa sand) when present at a 10 μg g À1 concentration in each. A direct derivatization protocol and one involving the pre-extraction of the analyte were evaluated for their individual efficiencies and subsequent analysis using electron ionization GC/MS. Results:The practical derivatization of 3Q, when present at low levels (10 μg g À1 ) in three different soil matrices, was found to be rapid (1 h) and to take place smoothly at ambient temperature (and as low as 4 C). The method detection limit was determined to be 30 ng mL À1 for the Virginia type A soil, 49 ng mL À1 for the Nebraska EPA standard soil and 72 ng mL À1 for the Ottawa sand sample.Conclusions: An expedient and practical derivatization method for 3Q, a chemical warfare degradation product difficult to detect by GC/MS, has been realized using trichloroethyl chloroformate. The reaction provides 3Q-Troc, a derivative with better detectability than 3Q by electron ionization GC/MS such as peak sharpness and a unique mass spectrum for its unambiguous identification.

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“…The polar acidic chemicals extracted from the matrixes are usually derivatized by variety of derivatizing methods and most important among them are silylation with silylating agents such as N , O ‐bis(trimethylsilyl)trifluoroacetamide and t ‐butyldimethyl silyl chloride and methylation with diazomethane, dimethyl acetals, and phenyltrimethyl ammonium hydroxides. Apart from these methods many other alternative alkylation methods were reported . Alternatively, ion‐pair (IP) extraction methods were developed using the reverse phase adsorbents and the interfering substances could be removed successfully .…”

Section: Introductionmentioning

confidence: 99%

Quantitative determination of acidic hydrolysis products of Chemical Weapons Convention related chemicals from aqueous and soil samples using ion‐pair solid‐phase extraction and in situ butylation

Anagoni

Kauser

Maity

et al. 2017

J of Separation Science

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Chemical warfare agents such as organophosphorus nerve agents, mustard agents, and psychotomimetic agent like 3-quinuclidinylbenzilate degrade in the environment and form acidic degradation products, the analysis of which is difficult under normal analytical conditions. In the present work, a simultaneous extraction and derivatization method in which the analytes are butylated followed by gas chromatography and mass spectrometric identification of the analytes from aqueous and soil samples was carried out. The extraction was carried out using ion-pair solid-phase extraction with tetrabutylammonium hydroxide followed by gas chromatography with mass spectrometry in the electron ionization mode. Various parameters such as optimum concentration of the ion-pair reagent, pH of the sample, extraction solvent, and type of ion-pair reagent were optimized. The method was validated for various parameters such as linearity, accuracy, precision, and limit of detection and quantification. The method was observed to be linear from 1 to 1000 ng/mL range in selected ion monitoring mode. The extraction recoveries were in the range of 85-110% from the matrixes with the limit of quantification for alkyl phosphonic acids at 1 ng/mL, thiodiglycolic acid at 20 ng/mL, and benzilic acid at 50 ng/mL with intra- and interday precisions below 15%. The developed method was applied for the samples prepared in the scenario of challenging inspection.

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Thermally assisted methylation and subsequent silylation of scheduled acids of chemical weapon convention for on-site analysis and its comparison with the other methods of methylation

Cited by 19 publications

References 27 publications

Structural determination of nerve agent markers using gas chromatography mass spectrometry after derivatization with 3‐pyridyldiazomethane

Structural determination of nerve agent markers using gas chromatography mass spectrometry after derivatization with 3‐pyridyldiazomethane

Trocylation of 3‐quinuclidinol, a key marker for the chemical warfare agent 3‐quinuclidinyl benzilate, for its enhanced detection at low levels in complex soil matrices by electron ionization gas chromatography–mass spectrometry

Quantitative determination of acidic hydrolysis products of Chemical Weapons Convention related chemicals from aqueous and soil samples using ion‐pair solid‐phase extraction and in situ butylation

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