Phenylarsonic Acid Research Articles

Comparison of the anion inhibition profiles of the β- and γ-carbonic anhydrases from the pathogenic bacterium Burkholderia pseudomallei

We report the cloning, purification and characterization of BpsβCA, a β-class carbonic anhydrase (CA, EC 4.2.1.1) from the pathogenic bacterium Burkholderia pseudomallei, the etiological agent of melioidosis, and compare its activity and inhibition with those of the γ-CA from the same organism, BpsγCA, recently investigated by our groups. BpsβCA showed a significant catalytic activity for the physiologic, CO2 hydration reaction, with the following kinetic parameters, kcat of 1.6×105s−1 and kcat/Km of 3.4×107M−1×s−1. The inhibition of BpsβCA with a group of anions and small molecules was also investigated. The best inhibitors were sulfamide, sulfamic acid and phenylarsonic acid, which showed KIs in the range of 83–92µM, whereas phenylboronic acid, fluoride, cyanide, azide, bisulfite, tetraborate, perrhenate, perruthenate, peroxydisulfate, perchlorate, tetrafluoroborate, fluorosulfonate and hexafluorophosphate showed KIs>100mM. Other inhibitors of this new enzyme were bicarbonate, trithiocarbonate, some complex inorganic anions and N,N-diethyldithiocarbamate, which had inhibition constants of 0.32–8.6mM. As little is known of the life cycle and virulence of this bacterium, this type of study may bring information of interest for the development of novel strategies to fight bacterial infection and drug resistance to commonly used antibiotics.

Anion inhibition profiles of the γ-carbonic anhydrase from the pathogenic bacterium Burkholderia pseudomallei responsible of melioidosis and highly drug resistant to common antibiotics

Burkholderia pseudomallei is a Gram-negative saprophytic bacterium responsible of melioidosis, an endemic disease of tropical and sub-tropical regions of the world. A recombinant γ-CA (BpsγCA) identified in the genome of this bacterium was cloned and purified. Its catalytic activity and anion inhibition profiles were investigated. The enzyme was an efficient catalyst for the CO2 hydration showing a kcat of 5.3×105s−1 and kcat/Km of 2.5×107M−1×s−1. The best BpsγCA inhibitors were sulfamide, sulfamic acid, phenylboronic acid and phenylarsonic acid, which showed KI in the range of 49–83μM (these inhibitors showed millimolar inhibition constant against hCA II), followed by diethyldithiocarbamate, selenate, tellurate, perrhenate, selenocyanate, trithiocarbonate, tetraborato, pyrophosphate, stannate, carbonate, bicarbonate, azide, cyanide, thiocyanate and cyanate with KIs in the range of 0.55–9.1mM. In our laboratories, work is in progress to resolve the X-ray crystal structures of BpsγCA, which may allow the development of small molecule inhibitors with desired properties for targeting and inhibiting specifically the bacterial over the human CAs, considering the fact that B. pseudomallei is involved in a serious bacterial disease.

Anion inhibition profiles of the complete domain of the η-carbonic anhydrase from Plasmodium falciparum

We have cloned, purified and investigated the catalytic activity and anion inhibition profiles of a full catalytic domain (358 amino acid residues) carbonic anhydrase (CA, EC 4.2.1.1) from Plasmodium falciparum, PfCAdom, an enzyme belonging to the η-CA class and identified in the genome of the malaria-producing protozoa. A truncated such enzyme, PfCA1, containing 235 residues was investigated earlier for its catalytic and inhibition profiles. The two enzymes were efficient catalysts for CO2 hydration: PfCAdom showed a kcat of 3.8×105s−1 and kcat/Km of 7.2×107M−1×s−1, whereas PfCA showed a lower activity compared to PfCAdom, with a kcat of 1.4×105s−1 and kcat/Km of 5.4×106M−1×s−1. PfCAdom was generally less inhibited by most anions and small molecules compared to PfCA1. The best PfCAdom inhibitors were sulfamide, sulfamic acid, phenylboronic acid and phenylarsonic acid, which showed KIs in the range of 9–68μM, followed by bicarbonate, hydrogensulfide, stannate and N,N-diethyldithiocarbamate, which were submillimolar inhibitors, with KIs in the range of 0.53–0.97mM. Malaria parasites CA inhibition was proposed as a new strategy to develop antimalarial drugs, with a novel mechanism of action.

Legionella pneumophila Carbonic Anhydrases: Underexplored Antibacterial Drug Targets.

Carbonic anhydrases (CAs, EC 4.2.1.1) are metalloenzymes which catalyze the hydration of carbon dioxide to bicarbonate and protons. Many pathogenic bacteria encode such enzymes belonging to the α-, β-, and/or γ-CA families. In the last decade, enzymes from some of these pathogens, including Legionella pneumophila, have been cloned and characterized in detail. These enzymes were shown to be efficient catalysts for CO2 hydration, with kcat values in the range of (3.4–8.3) × 105 s−1 and kcat/KM values of (4.7–8.5) × 107 M−1·s−1. In vitro inhibition studies with various classes of inhibitors, such as anions, sulfonamides and sulfamates, were also reported for the two β-CAs from this pathogen, LpCA1 and LpCA2. Inorganic anions were millimolar inhibitors, whereas diethyldithiocarbamate, sulfamate, sulfamide, phenylboronic acid, and phenylarsonic acid were micromolar ones. The best LpCA1 inhibitors were aminobenzolamide and structurally similar sulfonylated aromatic sulfonamides, as well as acetazolamide and ethoxzolamide (KIs in the range of 40.3–90.5 nM). The best LpCA2 inhibitors belonged to the same class of sulfonylated sulfonamides, together with acetazolamide, methazolamide, and dichlorophenamide (KIs in the range of 25.2–88.5 nM). Considering such preliminary results, the two bacterial CAs from this pathogen represent promising yet underexplored targets for obtaining antibacterials devoid of the resistance problems common to most of the clinically used antibiotics, but further studies are needed to validate them in vivo as drug targets.

Anion inhibition profiles of α-, β- and γ-carbonic anhydrases from the pathogenic bacterium Vibrio cholerae

Among the numerous metalloenzymes known to date, carbonic anhydrase (CA, EC 4.2.1.1) was the first zinc containing one, being discovered decades ago. CA is a hydro-lyase, which catalyzes the following hydration–dehydration reaction: CO2+H2O⇋HCO3−+H+. Several CA classes are presently known, including the α-, β-, γ-, δ-, ζ- and η-CAs. In prokaryotes, the existence of genes encoding CAs from at least three classes (α-, β- and γ-class) suggests that these enzymes play a key role in the physiology of these organisms. In many bacteria CAs are essential for the life cycle of microbes and their inhibition leads to growth impairment or growth defects of the pathogen. CAs thus started to be investigated in detail in bacteria, fungi and protozoa with the aim to identify antiinfectives with a novel mechanism of action. Here, we investigated the catalytic activity, biochemical properties and anion inhibition profiles of the three CAs from the bacterial pathogen Vibrio cholera, VchCA, VchCAβ and VchCAγ. The three enzymes are efficient catalysts for CO2 hydration, with kcat values ranging between (3.4−8.23)×105s−1 and kcat/KM of (4.1−7.0)×107M−1s−1. A set of inorganic anions and small molecules was investigated for inhibition of these enzymes. The most potent VchCAγ inhibitors were N,N-diethyldithiocarbamate, sulfamate, sulfamide, phenylboronic acid and phenylarsonic acid, with KI values ranging between 44 and 91μM.

Mechanism, kinetics, and pathways of self-sensitized sunlight photodegradation of phenylarsonic compounds

Being highly water-soluble, phenylarsonic feed additives discharged in animal wastes can easily accumulate in surface water bodies. The photodegradation mechanism, kinetics, and pathways of p-arsanilic acid (p-ASA), 4-hydrophenylarsonic acid (4-HPAA), and phenylarsonic acid (PAA) in water under simulated and natural sunlight irradiation were investigated. The -AsO(OH)2 group was cleaved from the aromatic ring during photodegradation, and p-benzoquinone and p-hydroquinone were formed as the major organic degradation intermediates. Experimental results did not indicate any significant direct photolysis of the phenylarsonic compounds under simulated and natural sunlight irradiation, but consistently showed that they sensitized the formation of singlet oxygen, which was responsible for their photodegradation and oxidation of the As(III) released. A simple 1O2-based “heterogeneous” model was developed, which could well describe the kinetics of 1O2 formation and phenylarsonic compound photodegradation under various conditions. Indirect photolysis caused by inorganic ions commonly present in natural waters was negligible, while natural organic matter could significantly inhibit their photodegradation. The half-lives of p-ASA, 4-HPAA, and PAA photodegradation under simulated sunlight irradiation (765 W m−2, 25 °C) were 11.82 ± 0.19, 20.06 ± 0.10, and 135 ± 6.0 min, respectively, while their degradation rates under natural sunlight in the Pearl River Delta of southern China were 5 times slower due to lower irradiation intensity and water temperatures (19–23 °C).

Anion inhibition studies of the β-carbonic anhydrase from the pathogenic bacterium Vibrio cholerae.

The genome of the pathogenic bacterium Vibrio cholerae encodes for three carbonic anhydrases (CAs, EC 4.2.1.1) belonging to the α-, β- and γ-classes. Here we report and anion inhibition study of the β-CA, VchCAβ with anions and other small molecules which inhibit metalloenzymes. The best VchCAβ anion inhibitors were sulfamide, sulfamate, phenylboronic acid and phenylarsonic acid, which showed KIs in the range of 54-86μM. Diethyldithiocarbonate was also an effective VchCAβ inhibitor, with an inhibition constant of 0.73mM. The halides, cyanate, thiocyanate, cyanide, bicarbonate, carbonate, nitrate, nitrite, stannate, selenate, tellurate, divanadate, tetraborate, perrhenate, perruthenate, peroxydisulfate, selenocyanide, trithiocarbonate, and fluorosulfonate showed affinity in the low millimolar range, with KIs of 2.3-9.5mM. Identification of selective inhibitors of VchCAβ (over the human CA isoforms) may lead to pharmacological tools useful for understanding the physiological role(s) of this under-investigated enzyme.

Cloning, characterization and anion inhibition studies of a γ-carbonic anhydrase from the Antarctic bacterium Colwellia psychrerythraea

We have cloned, purified and characterized the γ-carbonic anhydrase (CA, EC 4.2.1.1) present in the genome of the Antarctic bacterium Colwellia psychrerythraea, which is an obligate psychrophile. The enzyme shows a significant catalytic activity for the physiologic reaction of CO2 hydration to bicarbonate and protons, with the following kinetic parameters: kcat of 6.0×105s−1 and a kcat/Km of 4.7×106M−1×s−1. This activity was inhibited by the sulfonamide CA inhibitor (CAI) acetazolamide, with a KI of 502nM. A range of anions was also investigated for their inhibitory action against the new enzyme CpsCA. Perchlorate, tetrafluoroborate, fluoride and bromide were not inhibitory, whereas cyanate, thiocyanate, cyanide, hydrogensulfide, carbonate and bicarbonate showed KIs in the range of 1.4–4.4mM. Diethyldithiocarbamate was a better inhibitor (KI of 0.58mM) whereas sulfamide, sulfamate, phenylboronic acid and phenylarsonic acid were the most effective inhibitors detected, with KIs ranging between 8 and 38μM. The present study may shed some more light regarding the role that γ-CAs play in the life cycle of psychrophilic bacteria as the Antarctic one investigated here.

Determination of residual arsenic compounds in chicken muscle by ultra-performance liquid chromatography coupled with ultraviolet detection after pre-column derivatization with toluene-3,4-dithiol.

A simple and sensitive derivatization method using toluene-3,4-dithiol as a derivatization reagent for the simultaneous analysis of seven arsenic compounds (roxarsone, nitarsone, p-arsanilic acid, o-arsanilic acid, phenylarsonic acid, phenylarsine oxide, and mono-methylarsonic acid) in chicken muscle was developed and validated by ultra-performance liquid chromatography coupled with ultraviolet detection (UPLC-UV). The structure of the derivatized arsenic compounds was confirmed by liquid chromatography-ion trap mass spectrometry or gas chromatography-mass spectrometry. Optimization of the derivatization reaction conditions was carried out by investigating the influence of reagent concentration, buffer or additive acids, temperature, and time. The optimized conditions were a derivatization reagent concentration of 20mg/mL with 0.05mol/L HCl as an additive acid at 60°C for 15min. In this study, baseline separation of arsenic compounds could be achieved within 13min, except for phenylarsonic acid and phenylarsine oxide whose derivatized products are equal. The developed method was successfully validated and applied to 12 chicken muscle samples from Korean districts and other countries.

Anion inhibition studies of the dandruff-producing fungus Malassezia globosa β-carbonic anhydrase MgCA.

The genome of the fungal parasite Malassezia globosa, the causative agent of dandruff, contains a single gene annotated as encoding a carbonic anhydrase (CAs, EC 4.2.1.1) belonging to the β-class (MgCA). In an earlier work (J. Med. Chem. 2012, 55, 3513) we have validated this enzyme as an anti-dandruff drug target, reporting that sulfonamide inhibitors show in vitro and in vivo effects, in an animal model of Malassezia infection. However, few classes of compounds apart the sulfonamides, were investigated for their activity against MgCA. Here we present an anion inhibition study of this enzyme, reporting that metal complexing anions such as cyanate, thiocyanate, cyanide, azide are weak MgCA inhibitors (KIs ranging between 6.81 and 45.2 mM) whereas bicarbonate (KI of 0.59 mM) and diethyldithiocarbamate (KI of 0.30 mM) together with sulfamide, sulfamate, phenylboronic acid and phenylarsonic acid were the most effective inhibitors detected so far, with KIs ranging between 83 and 94 μM. This study may help a better understanding of the inhibition profile of this enzyme and may offer the possibility to design new such modulators of activity belonging to different chemical classes.

Cloning, characterization and anion inhibition studies of a new γ-carbonic anhydrase from the Antarctic bacterium Pseudoalteromonas haloplanktis

A new γ-class carbonic anhydrase (CA, EC 4.2.1.1) was cloned, purified and characterized from the Antarctic bacterium Pseudoalteromonas haloplanktis, PhaCAγ. The enzyme has a medium-low catalytic activity for the physiologic reaction of CO2 hydration to bicarbonate and protons, with a kcat of 1.4×105s−1 and a kcat/Km of 1.9×106M−1s−1. An anion inhibition study of PhaCAγ with inorganic anions and small molecule inhibitors is also reported. Many anions present in sea water, such as chloride, fluoride, sulfate, iodide, but also others such as azide, perchlorate and tetrafluoroborate did not inhibit this enzyme. Pseudohalides such as cyanate, thiocyanate, cyanide, selenocyanide, and also bicarbonate, nitrate, nitrite and many complex inorganic anions showed inhibition in the millimolar range (KI in the range of 1.7–9.3mM). The best PhaCAγ inhibitors detected in this study were diethyldithiocarbamate (KI of 0.96mM) as well as sulfamide, sulfamate, phenylboronic acid and phenylarsonic acid (KI in the range of 82–91μM). Since γ-CAs are poorly understood at this moment, being present in carboxysomes and thus involved in photosynthesis, this study may be relevant for a better understanding of these processes in Antarctic bacteria/cyanobacteria.

Structure and inhibition studies of a type II beta-carbonic anhydrase psCA3 from Pseudomonas aeruginosa

Carbonic anhydrases (CAs) are metallo-enzymes that catalyze the reversible hydration of carbon dioxide into bicarbonate and a proton. The β-class CAs (β-CAs) are expressed in prokaryotes, fungi, plants, and more recently have been isolated in some animals. The β-CA class is divided into two subclasses, termed type I and II, defined by pH catalytic activity profile and active site structural configuration. Type I β-CAs display catalytic activity over a broad pH range (6.5–9.0) with the active site zinc tetrahedrally coordinated by three amino acids and a hydroxide/water. In contrast, type II β-CAs are catalytically active only at a pH 8 and higher where they adopt a functional active site configuration like that of type I. However, below pH 8 they are conformationally self-inactivated by the addition of a fourth amino acid coordinating the zinc and thereby displacing the zinc bound solvent. We have determined the structure of psCA3, a type II β-CA, isolated from Pseudomonas aeruginosa (P. aeruginosa) PAO1 at pH 8.3, in its open active state to a resolution of 1.9Å. The active site zinc is coordinated by Cys42, His98, Cys101 and a water/hydroxide molecule. P. aeruginosa is a multi-drug resistant bacterium and displays intrinsic resistance to most of the currently used antibiotics; therefore, there is a need for new antibacterial targets. Kinetic data confirm that psCA3 belongs to the type II subclass and that sulfamide, sulfamic acid, phenylboronic acid and phenylarsonic acid are micromolar inhibitors. In vivo studies identified that among six tested inhibitors representing sulfonamides, inorganic anions, and small molecules, acetazolamide has the most significant dose-dependent inhibitory effect on P. aeruginosa growth.

Silica sequentially modified with polyhexamethylene guanidine and Arsenazo I for preconcentration and ICP–OES determination of metals in natural waters

Silica based sorbent sequentially modified with polyhexamethylene guanidine and 2-(1,8-dihydroxy-3,6-disulfo-2-naphthylazo)benzenearsonic acid (Arsenazo I) was developed and studied in the present work. Conditions for immobilizing Arsenazo I on the aminated silica surface were studied: optimal equilibration time was 10min, and a maximum reagent extraction was achieved between pHs4 and 7. The stability of the sorbent in highly saline and weakly acidic solutions was examined: it was found that the reagent had not been desorbed from the surface by treatment with dilute solutions of HNO3 and NaCl solutions up to a concentration of 10g/L. Maximum recovery of Al(III), Ca(II), Cd(II), Co(II), Cu(II), Fe(II), Fe(III), Mg(II), Ni(II), Pb(II), and Sr(II) was observed in the pH range of 5–7. Metals were desorbed from the surface with 1M HNO3. Sorption-inductively coupled plasma optical emission method for the determination of metal ions had been developed, including group sorption preconcentration of metal ions from aqueous solutions at pH7 in the hydrocarbonate buffer medium, their desorption with 1M HNO3, and inductively coupled plasma optical emission determination. The proposed method was used to determine metal concentration in river waters of Krasnoyarsk Krai.

Cloning, characterization and anion inhibition study of a β-class carbonic anhydrase from the caries producing pathogen Streptococcus mutans

The oral pathogenic bacterium involved in human dental caries formation Streptococcus mutans, encodes for two carbonic anhydrase (CA, EC 4.2.1.1) one belonging to the α- and the other one to the β-class. This last enzyme (SmuCA) has been cloned, characterized and investigated for its inhibition profile with a major class of CA inhibitors, the inorganic anions. Here we show that SmuCA has a good catalytic activity for the CO2 hydration reaction, with kcat 4.2×105s−1 and kcat/Km of 5.8×107M−1×s−1, being inhibited by cyanate, carbonate, stannate, divannadate and diethyldithiocarbamate in the submillimolar range (KIs of 0.30–0.64mM) and more efficiently by sulfamide, sulfamate, phenylboronic acid and phenylarsonic acid (KIs of 15–46μM). The anion inhibition profile of the S. mutans enzyme is very different from other α- and β-CAs investigated earlier. Identification of effective inhibitors of this new enzyme may lead to pharmacological tools useful for understanding the role of S. mutans CAs in dental caries formation, and eventually the development of pharmacological agents with a new mechanism of antibacterial action.

Photoluminescent lead(II) coordination polymers stabilised by bifunctional organoarsonate ligands

Four lead(II) coordination polymers were isolated under hydro(solvo)thermal conditions. The applied synthetic methodology takes advantage of the coordination behaviour of a new bifunctional organoarsonate ligand, 4-(1, 2, 4-triazol-4-yl)phenylarsonic acid (H2TPAA) and involves the variation of lead(II) reactants, metal/ligand mole ratios, and solvents. The constitutional composition of the four lead(II) coordination polymers can be formulated as [Pb2(TPAA)(HTPAA)(NO3)]·6H2O (1), [Pb2(TPAA)(HTPAA)2]·DMF·0.5H2O (DMF = N, N-Dimethylformamide) (2), [Pb2Cl2(TPAA)H2O] (3), and [Pb3Cl(TPAA)(HTPAA)2H2O]Cl (4). The compounds were characterized by single-crystal and powder x-ray diffraction techniques, thermogravimetric analyses, infra-red spectroscopy, and elemental analyses. Single-crystal x-ray diffraction reveals that 1 and 2 represent two-dimensional (2D) layered structures whilst 3 and 4 form three-dimensional (3D) frameworks. The structures of 1, 2, and 4 contain one-dimensional (1D) {PbII/AsO3} substructures, while 3 is composed of 2D {PbII/AsO3} arrays. Besides their interesting topologies, 1–4 all exhibit photoluminescence properties in the solid state at room temperature.

Cloning, characterization and anion inhibition studies of a γ-carbonic anhydrase from the Antarctic cyanobacterium Nostoc commune.

We report the cloning and catalytic activity of a γ-carbonic anhydrase (CA, EC 4.2.1.1) isolated from the Antarctic cyanobacterium Nostoc commune, NcoCA. The enzyme has a significant catalytic activity for the physiologic reaction, CO2 hydration to bicarbonate and protons, with a k(cat) of 9.5×10(5) s(-1) and a k(cat)/K(m) of 8.3×10(7) M(-1) × s(-1), being the most catalytically efficient γ-CA investigated so far. An anion inhibition study of NcoCA with inorganic/organic anions is also reported here. Fluoride, sulfate, perchlorate and tetrafluoroborate did not inhibit appreciably NcoCA, whereas the other halides, pseudohalides, bicarbonate, nitrate, nitrite and many complex inorganic anions showed inhibition in the millimolar range. The best NcoCA inhibitors detected so far were diethyldithiocarbamate (K(I) of 0.80 mM) as well as sulfamide, sulfamate, phenylboronic acid and phenylarsonic acid (K(I)s in the range of 70-90 μM). Since γ-CAs are present in carboxysomes, being involved in photosynthesis, this study may be relevant for a better understanding of such processes in some Antarctic organisms.

Crystal Growth, Structural Analysis, Characterization, Conformational Stability and Quantum Chemical Calculation of the Pharmaceutical Compound ? P-Arsanilic Acid

p-Arsanilic acid ,which is otherwise known as 4-amino phenyl arsonic acid, is a bioactive compound. Single crystals of p-Arsanilic acid (pAsA) are grown successfully under slow evaporation technique. The crystallinity and parameters of the grown crystal are determined with the powder x-ray diffraction result. The functional groups are characterized by FTIR and FT-RAMAN spectra. The UV spectrum reveals its application in the optoelectronic field. The molecular structure of the title compound is studied using density functional theory (DFT). The vibrational frequencies and the potential energy distribution (PED) are calculated using DFT/B3LYP 6-31+G** basis set. The stability of the molecule is determined by various conformers in the computational method. The HOMO-LUMO (Highest Occupied Molecular Orbital – Lowest Unoccupied Molecular Orbital) charge transfer and Non-Linear Optical (NLO) property determination were carried out. The electrophilic and nucleophilic attack of the molecule is studied using the MEP (Molecular Electrostatic Potential). The theoretical prediction of the thermodynamic properties helps in analysing the future application of the title compound.

Theoretical Inhibition Efficiency Study of Schiff Base (E)-2-(2-hydroxybenzylideneamino)phenylarsonic Acid and its Isomers

Theoretical Inhibition Efficiency Study of Schiff Base (E)-2-(2-hydroxybenzylideneamino)phenylarsonic Acid and its Isomers

(E)-2-[(2-hydroxybenzylidene)amino]phenylarsonic acid Schiff base: Synthesis, characterization and theoretical studies

The structure of the Schiff base (E)-2-[(2-hydroxybenzylidene)amino]phenylarsonic [(E)-HBAPhAA], synthesized from salicylaldehyde and o-aminophenylarsonic acid in the presence of HCl, was characterized by FTIR, 1H NMR, EI-MS, UV–Vis spectroscopy, and X-ray crystallography. The crystal belonged to the monoclinic space group P21/c. Two molecules formed a dimer via intermolecular interactions due to the attachment of H atoms to O1, O3 and O4 with OH bond distances within reasonable ranges, ca. 0.84(3)Å. The structure also showed two intramolecular interactions of 2.634(2) and 3.053(2)Å for NH⋯O hydrogen bonds, which caused the structures to be almost planar. We performed a theoretical analysis using DFT theory at B3LYP/6-31+G(d,p) level to determine the stability of the E and Z conformers. The geometry analysis of the E- and Z-isomers revealed an interconversion energy barrier between E/Z isomers of 22.72kcalmol−1. We also theoretically analyzed the keto form of the E-isomer and observed a small energy barrier for the tautomerization of 6.17kcalmol−1.

Selectively adsorptive extraction of phenylarsonic acids in chicken tissue by carboxymethyl α-cyclodextrin immobilized Fe3O4 magnetic nanoparticles followed ultra performance liquid chromatography coupled tandem mass spectrometry detection.

Carboxymethyl α-cyclodextrin immobilized Fe3O4 magnetic nanoparticles (CM-α-CD-Fe3O4) were synthesized for the selectively adsorptive extraction of five phenylarsonic acids including p-amino phenylarsonic acid, p-nitro phenylarsonic acid, p-hydroxy phenylarsonic acid, p-acylamino phenylarsonic acid and p-hydroxy-3-nitro phenylarsonic acid in chicken tissue. Using ultra performance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS), a highly sensitive analytical method was proposed for the determination of five phenylarsonic acids. It was shown that CM-α-CD-Fe3O4 could extract the five phenylarsonic acids in complex chicken tissue samples with high extraction efficiency. Under the optimal conditions, a high enrichment factor, ranging from 349 to 606 fold, was obtained. The limits of detection (LODs) (at a signal-to-noise ratio of 3) were in the range of 0.05–0.11 µg/kg for the five phenylarsonic acids. The proposed method was applied for the determination of five target phenylarsonic acids in chicken muscle and liver samples. Recoveries for the spiked samples with 0.2 µg/kg, 2.0 µg/kg and 20 µg/kg of each phenylarsonic acids were in the range of 77.2%–110.2%, with a relative standard deviation (RSD) of less than 12.5%.