Determination of alkylphosphonic acids by microcolumn liquid chromatography with gradient elution coupled on-line with flame photometric detection

Microcolumn liquid chromatography with gradient elution and on-line flame photometric detection has been used for the selective and rapid determination of non-volatile alkylphosphonic acids, which are hydrolysis products of nerve agents, in aqueous samples. A make-up of water was used to maintain stable introduction of the eluent during a gradient run. The detection limits are strongly dependent on quenching, which is determined by the mass flow of methanol in the eluent. Large-volume injections of 100 microl of aqueous solutions of short- and long-chain alkylphosphonic acids resulted in detection limits in the range 6-800 ng/ml. The repeatability of the retention times and analyte response - peak area or peak height were 0.7-0.9% and 4-11%, respectively. The method was successfully applied to a local tap water sample and an aqueous soil extract.     

Sensitive detection of phosphopeptides by matrix-assisted laser desorption/ionization mass spectrometry: use of alkylphosphonic acids as matrix additives

Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) has been one of the most powerful tools for analyzing protein phosphorylation. However, it is frequently difficult to detect phosphopeptides with high sensitivity by MALDI-MS. In our investigation of matrix/matrix-additive substances for improving the phosphopeptide ion response in MALDI-MS, we found that the addition of low-concentration alkylphosphonic acid to the matrix/analyte solution significantly enhanced the signal of phosphopeptides. In this study, the combination of methanediphosphonic acid and 2,5-dihydroxybenzoic acid gave the best results. In addition to enhancing the signal of the phosphopeptides, alkylphosphonic acid almost completely eliminated the signals of sodium and potassium ion adducts. We report herein sensitive detection of phosphopeptides by MALDI-MS with the use of alkylphosphonic acids as matrix additives.     

Separation and identification of isomeric acidic degradation products of organophosphorus chemical warfare agents by capillary electrophoresis-ion trap mass spectrometry

Capillary electrophoresis (CE) coupled to ion trap mass spectrometry (MS) was evaluated for the separation and identification of chemical warfare agent degradation products (alkylphosphonic acids and alkyl alkylphosphonic acids). Different analytical parameters were optimized in negative ionization mode such as electrolyte composition (15 mM CH(3)COONH(4), pH 8.8), sheath liquid composition (MeOH/H(2)O/NH(3), 75:25:2, v/v/v), nebulization and ion trapping conditions. A standard mixture of five alkylphosphonic (di)acids and five alkyl alkylphosphonic (mono)acids containing isomeric compounds was used in order to evaluate CE selectivity and MS identification capability. The obtained electropherograms revealed that CE selectivity was very limited in the case of alkyl alkylphosphonic acid positional isomers, whereas isomeric isopropylphosphonic and propylphosphonic acids were baseline-separated. CE-MS-MS experiments provided an unambiguous identification of each isomeric co-migrating alkyl alkylphosphonic acids thanks to the presence of specific fragment ions. On the other hand, CE separation was mandatory for the identification of isomeric alkylphosphonic acids, which led to the same fragment ion and could not be differentiated by MS-MS. The developed method was applied to the analysis of soil extracts spiked with the analytes (before or after extraction treatment) and appeared to be very promising since resolution and sensitivity were similar to those observed in deionized water. Especially, analytes were detected and identified in soil extract spiked at 5 microg mL(-1) with each compound before extraction treatment.     

Field-amplified sample stacking for the detection of chemical warfare agent degradation products in low-conductivity matrices by capillary electrophoresis-mass spectrometry

Preconcentration of chemical warfare agent degradation products (alkylphosphonic acids and alkyl alkylphosphonic acids) in low-conductivity matrices (purified water, tap water and local river water) by field-amplified sample stacking (FASS) was developed for capillary electrophoresis (CE) coupled to ion trap mass spectrometry. FASS was performed by adding a mixture of HCOONH(4) and NH(4)OH in appropriate concentrations to the sample. This allowed to control the conductivity and the pH of the sample in order to obtain FASS performances that are independent of analyte concentration. The influence of different parameters on FASS (sample to background electrolyte (BGE) conductivity ratio, injection volume and concentration of BGE) was studied to determine the optimal conditions and was rationalized by using the theoretical model developed by Burgi and Chien. A good correlation was obtained between the bulk electroosmotic velocity predicted by this model and the experimental value deduced from the migration time of the electroosmotic flow marker detected by mass spectrometry (MS). This newly developed method was successfully applied to the analysis of tap water and local river water fortified with the analytes and provided a 10-fold sensitivity enhancement in comparison to the signal obtained without preconcentration procedure. The quite satisfactory repeatability and linearity for peak areas obtained in the 0.5-5 microg mL(-1) concentration range allow quantitative analysis to be implemented. Limits of detection of 0.25-0.5 microg mL(-1) for the alkyl alkylphosphonic acids and of 0.35-5 microg mL(-1) for the alkylphosphonic acids were reached in tap water and river water.     

Direct detection of alkylphosphonic acids in environmental matrices by proton coupled phosphorus NMR

A simple, convenient, and direct one‐dimensional (1D) ³¹P NMR technique is demonstrated for the detection of alkylphosphonic acids (marker of nerve agents). The results of detection were validated after conducting various in‐house exercises. The confidence generated by this study was found very useful in detection of different alkylphosphonic acids spiked in various official interlaboratory proficiency tests conducted by Organisation for the Prohibition of Chemical Weapons (OPCW). Copyright © 2009 John Wiley & Sons, Ltd.     

Selective enrichment of the degradation products of organophosphorus nerve agents by zirconia based solid-phase extraction

Selective extraction and enrichment of nerve agent degradation products has been achieved using zirconia based commercial solid-phase extraction cartridges. Target analytes were O-alkyl alkylphosphonic acids and alkylphosphonic acids, the environmental markers of nerve agents such as sarin, soman and VX. Critical extraction parameters such as modifier concentration, nature and volume of washing and eluting solvents were investigated. Amongst other anionic compounds, selectivity in extraction was observed for organophosphorus compounds. Recoveries of analytes were determined by GC-MS which ranged from 80% to 115%. Comparison of zirconia based solid-phase extraction method with anion-exchange solid-phase extraction revealed its selectivity towards phosphonic acids. The limits of detection (LOD) and limit of quantification (LOQ) with selected analytes were achieved down to 4.3 and 8.5 ng mL(-1), respectively, in selected ion monitoring mode.     

Chemical modification of alumina and silica with alkylphosphonic acids and their esters

Alumina and silica were modified with alkylphosphonic acids and diethyl butylphosphonate. The boundaries of hydrolytic stability of the obtained surface-modified materials were determined.     

A Convenient Synthesis of ω-[(Arylphosphonomethyl)Amino] Alkylphosphonic and Carboxylic Acids via in Situ–Generated Arylideneaminoalkyl- Phosphonic or Carboxylic Acids

ω-[(Arylphosphonomethyl)amino]alkylphosphonic and carboxylic acids are prepared in an easy work-up procedure, by addition of diethyl phosphite to in situ–generated arylideneaminoalkylphosphonic or carboxylic acids followed by hydrolysis with hydrochloric acid     

A Convenient Synthesis of ω-(2-Aryl-4-oxothiazolidin-3-Yl)alkylphosphonic Acids via In Situ–Generated Arylideneaminoalkylphosphonic Acids

ω-(2-Aryl-4-oxothiazolidin-3-yl)alkylphosphonic acids are prepared in an easy workup procedure by the addition of methyl mercaptoacetate to in situ–generated arylideneaminoalkyl phosphonic acids.     

Determination of pentafluorobenzyl derivatives of phosphonic and phosphonothioic acids by gas chromatography-mass spectrometry

A method based on gas chromatography-mass spectrometry (GC/MS) has been evaluated and standardized for the analysis of pentafluorobenzyl (PFB) derivatives of alkylphosphonic, O-alkyl alkylphosphonic and phosphonothioic acids. The pentafluorobenzyl (PFB) derivatives are much more stable as compared to the conventionally used trimethylsilyl derivatives. The conditions for the derivatization and analysis have been optimized to achieve the best detection limits in negative chemical ionization (NCI) mode.     

Determination of hydrolytic degradation products of nerve agents by injection port fluorination in gas chromatography/mass spectrometry for the verification of the Chemical Weapons Convention

Retrospective detection and identification of markers of chemical warfare agents are important aspects of verification of the Chemical Weapons Convention. Alkyl alkylphosphonic acids (AAPAs) and alkylphosphonic acids (APAs) are important markers of nerve agents. We describe the development and optimization of a new gas chromatography/mass spectrometry (GC/MS) injection port fluorination method for the derivatization of AAPAs and APAs. The process involved the injection of acids with trifluoroacetic anhydride in GC/MS, where acids are converted into their corresponding volatile fluorides. Various reaction conditions such as fluorinating agent, injection port temperature and splitless time were optimized. The maximum reaction efficiency of the acids with trifluoroacetic anhydride was observed at 230 degrees C injection port temperature with a splitless time of 2 min. APAs showed best analytical efficiencies at 400 degrees C injection port temperature, while the other conditions were similar to those of AAPAs. The linearities of response for APAs and AAPAs were in the range of 1-25 and 5-100 microg mL(-1), respectively, with limits of detection ranging from 500 pg to 800 ng mL(-1).     

Highly-ordered layered organo-mineral materials prepared via reactions of n-alkylphosphonic acids with apatite

This work describes a novel class of layered organo-mineral materials manufactured via a single-step solution-phase reaction of n-alkylphosphonic acids (CnH(2n+1)P(O)(OH)2) with calcium hydroxyapatite mineral (CaHAP). TEM, SAXS, WAXS, FTIR, and Vapor Phase Adsorption data suggest that these alkyl-CaHAP materials present a surface-modified CaHAP matrix coated with ordered layers of calcium alkylphosphonates that are strongly adhered to the surface. Interlayer spacing increases from 1.47 (C3-CaHAP) to 4.77 nm (C18-CaHAP). According to FTIR, ordering of alkyl chains improves with the alkyl chain length. The organic loads in these alkyl-CaHAP can be controlled over a wide range (up to approximately 60%) by varying alkyl chain and the concentration of alkylphosphonic acids in the solution.     

Mild and efficient esterification of alkylphosphonic acids using polymer-bound triphenylphosphine

Mild and efficient esterification of alkylphosphonic acids using primary alcohols, iodine, imidazole and polymer-bound triphenylphosphine is developed.     

Study of mechanism retention of nonvolatile alkylphosphonic acids on unmodified selected polymer-based ion exchanger columns

The retention of alkylphosphonic acids (MPA, EPA, PPA, and BPA) and inorganic anions (Cl⁻, NO₃⁻, and SO₄²⁻) were studied on two anion exchangers, e.g., Dionex IonPac AS4A-SC (250 ± 4 mm I.D.) and Satisfaction P 4000-SAX (50 ± 4.6 mm I.D.) under isocratic elution conditions with evaporative light scattering detector. The plots of retention factors, k, of organic anions vs. the reciprocal of eluent ion concentration show good linearity. The major retention mechanisms are interpreted as ion exchange and some others interactions. The C effect of organic modifier added to the aqueous buffered mobile phase is also investigated.     

Polyfluoroalkoxy phosphonic and phosphinic acid derivatives: II. Reversible esterase inhibitors

Polyfluoroalkyl esters of phosphoric, alkylphosphonic and 1-hydroxypolyfluoroalkylphosphonic acids exhibited significant antiesterase activity against various esterases of animal and microbial origin. Moreover, with some compounds reversible inhibition of enzymes was observed due to the specific influence of hydrophobic fragments of the target products.     

3-烷基取代吡咯单体的合成

通过电聚合沉积在基底上的聚吡咯膜容易剥离的问题可以通过粘合增强剂解决。我们设计并合成一类新化合物w-3-吡咯烷基磷酸将聚吡咯膜 通过化学键键合到金属基底上。本文描述了合成含有表面反应功能团的3-取代吡咯的过程。1-苯磺酰吡咯作为起始物经付-克反应得到3-取代吡咯。两种方法可以合成w-3-吡咯烷基磷酸酯。一种路线是：先磷酸化然后脱保护基最后还原羰基。这种方法适用于含有六个碳及以上的取代基。另一种路线是：先还原羰基然后磷酸化及脱保护。这种方法适用于短链及长链取代基。最后水解得到w-3-吡咯烷基磷酸。     

ω-substituted long chain alkylphosphonic acids – their synthesis and deposition on metal oxides and subsequent functional group conversion of the deposited compounds

The crystal structure and the surface of alumina layers on silicon wafers were investigated by means of GIWAXS, WAXS, and AFM. Self-assembled monolayers of ω-substituted long-chain alkylphosphonic acids were deposited on alumina and the layer thickness and homogeneity were determined by ellipsometry revealing a dependency of thickness and homogeneity on the nature of the substituent. During the adsorption process surface etching by the phosphonic acid was observed causing an increase in surface roughness. Furthermore, ex post functional group conversions were carried out yielding surface bound azides and rhodanides.     

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

On-site verification of the chemical weapon convention (CWC) requires provision for the detection and identification of alkyl phosphonic acids as well as some organic acids that are amenable to GC-MS only after derivatisation. Various derivatisation methods have been used for the identification of these acids and for many cases the methyl derivatives are less prone to artifacts possibly leading to false positive identification. Methylation with diazomethane is widely used but, especially for on-site analysis it has limitation due to the potential explosive and health hazards. Other methylation procedures like trimethylsilyldiazomethane (TMSD), thermally assisted methylation (TAM) by trimethylphenylammonium hydroxide (TMPAH) and trimethylsulfonium hydroxide (TMSH) are evaluated. Data for methylation for the alkyl alkylphosphonic acids, alkylphosphonic acids and benzilic acid are reported. In addition, TAM followed by the silylation in the same sample without any additional sample preparation is also reported. Several parameters such as solvent, temperature, amount of reagents, time, etc. were studied. The two commercially available reagents namely, TMPAH and TMSH for TAM and subsequent silylation were evaluated. The LOD with TMPAH was below 0.5 ng per injection since all of the acids were detected by GC-MS with the S/N of >3 in full scan mode by AMDIS and their inter day relative standard deviation was from 4.7% to 10.8%.     

Microsynthesis and mass spectral study of Chemical Weapons Convention related 2‐alkyl‐1,3,6,2‐dioxathiaphosphocane‐2‐oxides

Chemical Weapons Convention (CWC)‐related compounds where the phosphorus atom is part of a ring have very limited representation in mass spectral libraries and the open literature. Here we report electron ionization (EI), chemical ionization (CI) and electrospray ionization tandem mass spectrometry (ESI‐MSⁿ) spectra and retention indices for 2‐alkyl‐1,3,6,2‐dioxathiaphosphocane‐2‐oxides (alkyl C₁ to C₃) which are new cyclic chemicals covered under the CWC. The EI mass spectra show a pattern of ion fragmentation that is similar to that of other cyclic phosphonates in that loss of the alkylphosphonic acid as a neutral loss is more important than the presence of the protonated alkylphosphonic acid. In contrast to other cyclic phosphonates, the 2‐alkyl‐1,3,6,2‐dioxathiaphosphocane‐2‐oxides show almost no protonated alkylphosphonic acid and as a result the spectra do not carry the same distinctive signature of the phosphorus–carbon bond that is required for the chemical to be covered under the CWC. Copyright © 2008 John Wiley & Sons, Ltd.     

Polyfluoroalloxy phosphonic and phosphinic acid derivatives: I. 1-Hydroxy-2,2,2-trichloroethylphosphinates

Polyfluoroalkyl esters of phosphoric, alkylphosphonic and 1-hydroxypolyfluoroalkylphosphonic acids exhibited significant antiesterase activity against various esterases of animal and microbial origin. Moreover, with some compounds reversible inhibition of enzymes was observed due to the specific influence of hydrophobic fragments of the target products.