LC–MS and UPLC–Quadrupole Time-of-Flight MS for Identification of Photodegradation Products of Aflatoxin B1

UV irradiation of a solution of aflatoxin B₁ in acetonitrile resulted in three major degradation products which have been identified by LC–MS. Accurate masses and proposed molecular formulas of the degradation products—315.0868 (C₁₇H₁₅O₆), 285.0758 (C₁₆H₁₃O₅), and 275.0553 (C₁₄H₁₁O₆)—were obtained with low mass error and high matching property by ultra-performance liquid chromatography–quadrupole time-of-flight mass spectrometry (UPLC–Q-TOF MS). Structural formulas of the photodegradation products, and the degradation pathways leading to the compounds, are proposed on the basis of the molecular formulas and MS–MS spectra. UPLC–Q-TOF MS has been recognized as a powerful analytical tool for qualitative analysis of trace materials and degradation products.     

Modification of PVC. XXVI. Syntheses and photocrosslinking of polysulfide pendant poly(vinyl chloride)

Poly(vinyl chloride) pendant with polysulfide (PS–PVC) having various degrees of substitution, various S substituents, and various numbers of atoms in the sulfur chain has been synthesized by the reaction of poly(vinyl chloride) with a thiol, sulfur, and triethylamine in dimethylformamide at 30°C for 0.4–5 hr. The photocrosslinking reaction has been investigated under ultraviolet irradiation at 250–450 mμ. The photocrosslinking reaction of PS–PVC is influenced by the degree of substitution, the nature of the S substituent, and the number of atoms in the sulfur chain. The degree of photocrosslinking r increased in the order, n-C₄H₉? < n-C₈H₁₇? < C₆H₅CH₂? < i-C₃H₇? < t-C₄H₉? . On the photocrosslinking of PS–PVC having two different S substituents, r increases in the similar order for aliphatic substituents and in the order NO₂C₆H₄? < ClC₆H₄? < C₆H₅CH₂? < CH₃C₆H₄? < t-C₄H₉C₆H₄? < C₆H₅? for the aromatic substituents. Further, r increases markedly with the increase of sulfur chain number for all PS–PVC. The chemical structure of the crosslinks and the crosslinking mechanism are discussed on the basis of the results.     

Photodegradation kinetics and byproducts identification of the Aflatoxin B1 in aqueous medium by ultra‐performance liquid chromatography–quadrupole time‐of‐flight mass spectrometry

A photodegradation study of Aflatoxin B₁ (AFB₁) in water solution was performed under UV irradiation at different AFB₁ initial concentrations and UV irradiation intensities. The effect of UV intensity on the AFB₁ photodegradation ratio is dominative, when compared with AFB₁ initial concentration. The photodegradation of AFB₁ was proved to follow first‐order reaction kinetics (R² ≥ 0.99). Three photodegradation products, i.e. P₁ (C₁₇H₁₄O₇), P₂ (C₁₆H₁₄O₆) and P₃ (C₁₆H₁₂O₇), were identified on the basis of low mass error and high matching property by ultra‐performance liquid chromatography–quadrupole time‐of‐flight mass spectrometry (UPLC–Q‐TOF MS), and the degradation pathway was proposed. This study first reports the appearance of these photodegradation products and the proposed degradation pathway in aqueous media. Copyright © 2010 John Wiley & Sons, Ltd.     

Elucidation of phototransformation reactions of the X‐ray contrast medium iopromide under simulated solar radiation using UPLC‐ESI‐QqTOF‐MS

The highly polar, nonionic X‐ray contrast agent iopromide (C₁₈H₂₄N₃O₈I₃; 791 Da) is resistant to microbial degradation during the activated sludge process in wastewater treatment plants and hence is released into the aquatic environment. Against this background, the present study was conducted to evaluate the phototransformation, potentially constituting the most relevant removal mechanism in rivers and streams. The photolysis of the iodinated aromatic compound was investigated in a Suntest solar simulator using aqueous solutions. Following a 120‐min irradiation period, an almost complete primary degradation of iopromide gave rise to a series of photoproducts that were chromatographed on a reversed‐phase UPLC and subsequently characterized by a combination of accurate mass measurements on a ESI‐QqToF‐MS instrument and H/D‐exchange experiments. This analytical approach facilitated confident identification of eight prominent products with the following elemental compositions and molecular weights: C₁₈H₂₅N₃O₉I₂ (681 Da); C₁₈H₂₅N₃O₈I₂ (665 Da); C₁₇H₂₃N₃O₈I₂ (651 Da); C₁₈H₂₄N₃O₉I (553 Da); C₁₇H₂₄N₃O₈I (525 Da); C₁₅H₂₀N₃O₆I (465 Da); C₁₄H₁₈N₃O₆I (451 Da); and C₁₈H₂₅N₃O₉ (427 Da). Their formation was the result of four principal photoreactions: (1) gradual, and eventually complete, deiodination of the aromatic ring; (2) substitution of the halogen by a hydroxyl group; (3) N‐dealkylation of the amide in the hydroxylated side chain; and (4) oxidation of a methylene group in the hydroxylated side chain to the corresponding ketone. In conclusion, the findings of the artificial sunlight irradiation experiments indicated that in real environmental settings iopromide might suffer partial or even complete deiodination. Copyright © 2009 John Wiley & Sons, Ltd.     

The etching and optical response of Tuffak polycarbonate nuclear track detector to gamma irradiation

The effects of gamma irradiation in the dose range of 1.0–20.0 Mrad on the etching and optical characteristics of Tuffak polycarbonate (C₁₆H₁₄O₃)_n nuclear track detector have been studied by using etching and UV–visible spectroscopic techniques. The bulk etch rates increase and the activation energies for bulk etching decrease with the increase in gamma dose. The optical band gaps determined from the UV–visible spectra were found to decrease with the increase in gamma dose. These results have been explained on the basis of scission of the detector due to gamma irradiation.     

Enhanced formation of quercetin by combined use of gamma ray and H2O2 from cyanidin-3-O-xylosylrutinoside

Cyanidin-3-O-xylosylrutinoside (cya-3-O-xylrut), a major pigment in Schizandra chinensis Baillon, was effectively removed by gamma irradiation of greater than 2 kGy, whereas quercetin, the most abundant of the flavonoids and has anti-inflammatory and anti-allergic effects, could be generated by degradation of cya-3-O-xylrut. In the present study, we investigated the effect of combination treatment of gamma irradiation and hydrogen peroxide (H₂O₂) on the formation of quercetin through the degradation of cya-3-O-xylrut. Cya-3-O-xylrut was significantly degraded (～93%) by gamma irradiation at 2 kGy and it was completely removed by a combination treatment (0.2% H₂O₂ and 2 kGy gamma ray). The formation of quercetin was significantly appeared at 2 kGy of gamma ray, together with disappearance of cya-3-O-xylrut. The quercetin formation by gamma ray is 3.2 μg/ml and combination treatment is 7.7 μg/ml. Therefore, the combination treatment of H₂O₂ and gamma ray is more effective to convert cya-3-O-xylrut into quercetin than gamma irradiation only. In conclusion, gamma ray combined with H₂O₂ would be a promising tool for bio-conversion of organic compounds.     

Dimethyl phthalate (DMP) degradation in aqueous solution by gamma-irradiation/H<Subscript>2</Subscript>O<Subscript>2</Subscript>

This work includes the applications of radiation processing to decompose dimethyl phthalate (DMP) with gamma and gamma/H₂O₂ processes. Changes in amounts of DMP, dissolved oxygen, total acidity and formaldehyde with irradiation dose were followed. The qualitative analysis of the DMP and the intermediates were determined by using a gas chromatography combined to mass spectrometry and ion chromatography. The results indicated that degradation rate of DMP was affected by H₂O₂ concentration, irradiation dose and removal efficiency of 25 mg L^?1 DMP can reach 100% for 1.42 kGy irradiation dose in the concentration of 4.8 mM H₂O₂, respectively.     

Two rhod­amine derivatives: 9‐[2‐(ethoxycarbonyl)phenyl]‐3,6‐bis(ethyl­amino)‐2,7‐di­methyl­xanthyl­ium chloride monohydrate and 3,6‐di­amino‐9‐[2‐(methoxy­carbonyl)­phenyl]xanthyl­ium chloride trihydrate

The title compounds, C₂₈H₃₁N₂O₃⁺·Cl^?·H₂O (common name rhod­amine‐6g), (I), and C₂₁H₁₇N₂O₃⁺·Cl^?·3H₂O (common name rhod­amine‐123), (II), both have planar xanthene skeletons with a formal +1 charge on the amino N atoms delocalized through the π‐electron system so that the N—Csp² bond distances indicate significant double‐bond character. The substituted planar phenyl groups make angles of 63.29 (8) and 87.96 (11)° with the xanthene planes in (I) and (II), respectively. In both mol­ecules, the carbonyl bond vectors point toward the xanthene rings. The ethyl­amine groups in (I) are oriented similarly with their CH₂–CH₃ bond vectors pointing nearly perpendicular to the xanthene plane. The chloride ions and water mol­ecules are disordered in both structures. In (I), the chloride ion and water mol­ecule are disordered between two sites. One water and chloride alternately occupy the same site with occupancy factors of 0.5. The other 0.5‐chloride and 0.5‐water occupy two distinct positions separated by 0.747 (8) Å. In (II), the chloride ion is disordered between three sites and one of the waters is disordered about two other sites. Both crystal structures are stabilized by hydrogen bonds involving the chloride ions, amino groups and water mol­ecules, as well as by π–π stacking between xanthene planes.     

The anilinium chloride adduct of 4‐bromo‐N‐phenylbenzene­sulfonamide

The title compound anilinium chloride–4‐bromo‐N‐phenyl­benzene­sulfonamide (1/1), C₆H₈N⁺·Cl⁻·C₁₂H₁₀BrNO₂S, displays a hydrogen‐bonded ladder motif with four independent N—H⋯Cl bonds in which both the NH group of the sulfonamide molecule and the NH₃ group of the anilinium ion [N⋯Cl = 3.135 (3)–3.196 (2) Å and N—H⋯Cl = 151–167°] are involved. This hydrogen‐bonded chain contains two independent R₄²(8) rings and each chloride ion acts as an acceptor of four hydrogen bonds.     

Monolayer cuprous chloride dispersed on pillared clays for olefin-paraffin separations by π-complexation

New adsorbents containing cuprous chloride dispersed on pillared interlayered clays (PILC) have been prepared and studied for olefin-paraffin separations. High surface-area PILC's were synthesized with different metal oxide (Al₂O₃, Fe₂O₃, TiO₂ and ZrO₂) as the intercalating pillars. Cuprous chloride was dispersed in a submonolayer form on these PILC's. Pure-component isotherms were measured for C₂H₄, C₂H₆, C₃H₆ and C₃H₈ at 25°C and 60°C. All sorbents exhibited high C₂H₄/C₂H₆ and C₃H₆/C₃H₈ ratios with significantly high amounts of olefins adsorbed. The best sorbent was CuCl/TiO₂-PILC which showed a C₂H₄/C₂H₆ ratio of 5.3 and C₃H₆/C₃H₈=2.9 at 25°C. In all cases, olefins adsorbed by -complexation with Cu(I) ion, reflected by heats of adsorption in the range 10.7–13.7 kcal/mol, as compared to 4.8–6.9 kcal/mol for the physical adsorption of the paraffins. The -complexation was fully reversible, limited only by the rates of pore diffusion. Diffusion of C₂'s was rapid while for C₃'s the diffusion reached 60% completion in approximately 6 min. Comparing these results with those of CuCl/-Al₂O₃, the olefin/paraffin adsorption ratios were not as high as those of the later. However, the olefin isotherms on the PILC-supported CuCl displayed the desirable feature of having a steeper portion above the knee of the isotherm (the knee occurred at below 0.1 atm). This was a useful feature for separation because it yielded a larger working capacity. The steeper isotherm was attributed to a higher degree of energy heterogeneity as the PILC contained both surfaces of pillars and clay layers as opposed to only -Al₂O₃.     

Oxidation of benzalkonium chloride by gamma irradiation: kinetics and decrease in toxicity

The gamma degradation of toxic non-oxidizing biocide dodecyl dimethyl benzyl ammonium chloride (DDBAC) was investigated. The degradation of DDBAC achieved 70–100% depending on the initial concentration and the absorbed dose, but only 10–33% dissolved organic carbon was removed. The presence of NO₃ ^?, HCO₃ ^?, 2-propanol and tert-butanol inhibited the degradation of DDBAC. The DDBAC degradation rate constant ratios of ·OH, ·H and e _aq ^? was calculated as 7.4:1.4:1. The acute toxicity of 10 mg L^?1 DDBAC was removed by 60% at absorbed doses of 0.5–3.0 kGy. The results showed that gamma irradiation was effective to remove DDBAC and its toxicity.     

Phase equilibria in a ternary fullerenol-d(C<Subscript>60</Subscript>(OH)<Subscript>22–24</Subscript>)–SmCl<Subscript>3</Subscript>–H<Subscript>2</Subscript>O system at 25°C

The solubility in a ternary fullerenol-d (C₆₀(OH)_22–24)–SmCl₃–H₂O system at 25°C is studied via isothermal saturation in ampules. The solubility diagram is shown to be a simple eutonic one that consists of two branches corresponding to the crystallization of fullerenol-d (C₆₀(OH)_22–24 · 30H₂O) and samarium(III) chloride SmCl₃ · 6H₂O crystallohydrates and contains one nonvariant eutonic point corresponding to saturation with both crystallohydrates. The long branch of C₆₀(OH)_22–24 · 30H₂O crystallization shows the effect of fullerenol-d salting out of saturated solutions; in contrast, the short branch of SmCl₃ · 6H₂O crystallization shows the pronounced salting-in effect of samarium(III) chloride.     

Poly­[[aqua­neodymium(III)]‐μ3‐decane‐1,10‐di­carboxyl­ato‐μ3‐9‐carboxy­nonane­carboxyl­ato]

The title compound, [Nd(C₁₀H₁₆O₄)(C₁₀H₁₇O₄)(H₂O)]_n, has a novel Nd–organic framework constructed from sebacic acid (C₁₀H₁₈O₄) linkers, the longest aliphatic ligand used to date in lanthanide metal–organic framework compounds. The structure contains edge‐shared chains of NdO₈(H₂O) tricapped trigonal prisms that propagate in the [100] direction, with Nd—O distances in the range 2.414 (4)–2.643 (4) Å.     

A 119Sn Mössbauer study of the thermal degradation of organotin stabilisers in PVC

^119mSn Mössbauer studies of the thermal degradation of PVC containing the stabilisers dibutyltinbis ($\text{iso}$octylthioglycollate) (1.2% by weight of the polymer), dioctyltinbis ($\text{iso}$octylthioglycollate (4% by weight of the polymer) and dibutyltinbis ($\text{iso}$octylmaleate) (2% by weight of the polymer) indicate that in each case the stabiliser is converted into the dialkylmonochlorotin ester R₂SnCl(X) (X  SCH₂CO₂C₈H₁₇ or O₂C.CH  CHCO₂C₈H₁₇), and not into the dialkyltin dichloride, R₂SnCl₂, as recently suggested by other workers. Comparison of the Mössbauer data for organotin-stabilised PVC samples prepared by both hot-milling and room temperature solvent casting processes indicates that there is little degradation of the polymer (and stabiliser) during the initial hot-milling process.     

Tris(dimethylamido)bis(dimethylamine)titanium(IV) chloridobis(dimethylamine)[tris(pentafluorophenyl)boron–amido][tris(pentafluorophenyl)boron–nitrido]titanate(IV) toluene solvate

The title ionic solid, [Ti(C₂H₆N)₃(C₂H₇N)₂][Ti(C₁₈BF₁₅N)(C₁₈H₂BF₁₅N)Cl(C₂H₇N)₂]·C₇H₈, (I), comprises a cation with three dimethylamide ligands in the equatorial plane and two dimethylamine ligands positioned axially in a trigonal–bipyramidal geometry about the central Ti^IV atom. The anion has a highly distorted octahedral structure. The two dimethylamine ligands are coordinated mutually trans. The chloride is trans to the tris(pentafluorophenyl)boron–amide, while the sixth coordination site is occupied by an ortho‐F atom of the tris(pentafluorophenyl)boron–amide group in a trans disposition with respect to the tris(pentafluorophenyl)boron–nitride ligand. The most significant feature of the anion is the presence of an unprecedented terminal Ti[triple‐bond]N moiety [1.665 (2) Å], stabilized by coordination to B(C₆F₅)₃, with a Ti[triple‐bond]N—B angle of 169.50 (19)°.     

Synthese und Eigenschaften von Metallocen‐ und Halbsandwich‐Komplexen mit pyridinhaltigen Brücken bzw. Seitenketten

Synthesis and Properties of Metallocene and Half Sandwich Complexes with Pyridine‐containing Bridges or Side Chains 2,6‐Bis(chlormethyl)pyridine ( 1 ) reacts with 4 equivalents of indenyllithium with formation of 2,6bis(methylenindenyl)pyridine‐dilitihium ( 2 ) from which with MCl₄ · 2 thf (M = Zr, Hf) the corresponding metallocene dichlorides 3 and 4 can be obtained. At reaction of 1 with 2 equivalents of C₅H₅Na only one Cl atom is replaced by a C₅H₅Na unit. Following reactions with indenyl lithium and ZrCl₄ · 2 thf give the unsymmetric complex [C₅H₃N–2,6‐CH₂‐(2‐C₅H₄)–(6‐C₉H₆)ZrCl₂] ( 7 ). – Picolylcyclopentadiene ( 8 ) and 1‐(picolyl)‐indene ( 9 ) are synthesized from 2‐chlomethyl‐pyridinium chloride and C₅H₅Na or indenyl lithium respectively, which are transferred in the half sandwich complexes (C₅H₄N–CH₂C₅H₄)MCl₃ (M = Ti 10 , Zr 11 ) and (C₅H₄–CH₂C₉H₆)ZrCl₃ ( 12) . The compounds were characterized by elemental analysis, ¹H n.m.r., ms, ir, and raman spectra. N → M interactions are discussed.     

Transformations of the chameleon ligand 1,10‐phenanthroline‐5,6‐dione/diol: cis‐dichlorido(1,10‐phenanthroline‐5,6‐dione‐κ2N,N′)‐trans‐dipyridinecobalt(II) pyridine disolvate prepared from the diol

The title compound, [CoCl₂(C₅H₅N)₂(C₁₂H₆N₂O₂)]·2C₅H₅N, is a neutral Co^II complex with two chloride anions coordinated in a cis fashion, two pyridine ligands in trans positions and a chelating 1,10‐phenanthroline‐5,6‐dione ligand that completes the octahedral coordination geometry. Two pyridine solvent molecules reside in channels (about 7 × 4 Å wide; the closest atom–atom distance within the channel is 10 Å). The three‐dimensional structure supporting these channels is held together by C—H...Cl [3.466 (8)–3.670 (9) Å] and C—H...O [3.014 (9)–3.285 (8) Å] hydrogen bonds, and can be viewed as a CsCl or bcu (body‐centred cubic) net.     

Die Synthese aliphatischer Organophosphorverbindungen mit Hilfe von Diäthylaminodichlorphosphin

Zusammenfassung Diäthylaminodichlorohosphin, (C₂H₅)₂NPCl₂, hergestellt aus PCl₃ und Diäthylamin, reagierte mit C₈H₁₇MgBr zu Dioctylphosphinigsäure, (C₈H₁₇)₂P(O)H, die mit H₂O₂ zur Phosphinsäure oxydiert wurde. Polyoctamethylenphosphinsäure wurde in 67% Ausbeute als eine in organischen Lösungsmitteln unlösliche weiße Substanz in ähnlicher Weise, unter Verwendung von BrMg(CH₂)₈MgBr, erhalten. *** DIRECT SUPPORT *** A3615144 00016

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Synthesis of Aliphatic Organophosphorus compounds

Diethylaminodichlorophosphine, prepared from PCl₃ and diethylamine, reacted with C₈H₁₇MgBr to give dioctylphosphinous acid, (C₈H₁₇)₂P(O)H. Oxidation of this compound with H₂O₂ produced dioctylphosphinic acid, (C₈H₁₇)₂P(O)OH. In an analogous reaction sequence employing BrMg(CH₂)₈MgBr polyoctamethylenephosphinic acid was obtained in 67% yield. This polymer is insoluble in organic solvents.

     

Low‐dimensional compounds containing bioactive ligands. IV. Unusual ionic forms of 5‐chloroquinolin‐8‐ol

Bis(5‐chloro‐8‐hydroxyquinolinium) tetrachloridopalladate(II), (C₉H₇ClNO)₂[PdCl₄], (I), catena‐poly[dimethylammonium [[dichloridopalladate(II)]‐μ‐chlorido]], {(C₂H₈N)[PdCl₃]}_n, (II), ethylenediammonium bis(5‐chloroquinolin‐8‐olate), C₂H₁₀N₂²⁺·2C₉H₅ClNO⁻, (III), and 5‐chloro‐8‐hydroxyquinolinium chloride, C₉H₇ClNO⁺·Cl⁻, (IV), were synthesized with the aim of preparing biologically active complexes of Pd^II and Ni^II with 5‐chloroquinolin‐8‐ol (ClQ). Compounds (I) and (II) contain Pd^II atoms which are coordinated in a square‐planar manner by four chloride ligands. In the structure of (I), there is an isolated [PdCl₄]²⁻ anion, while in the structure of (II) the anion consists of Pd^II atoms, lying on centres of inversion, bonded to a combination of two terminal and two bridging Cl⁻ ligands, lying on twofold rotation axes, forming an infinite [–μ₂‐Cl–PdCl₂–]_n chain. The negative charges of these anions are balanced by two crystallographically independent protonated HClQ⁺ cations in (I) and by dimethylammonium cations in (II), with the N atoms lying on twofold rotation axes. The structure of (III) consists of ClQ⁻ anions, with the hydroxy groups deprotonated, and centrosymmetric ethylenediammonium cations. On the other hand, the structure of (IV) consists of a protonated HClQ⁺ cation with the positive charge balanced by a chloride anion. All four structures are stabilized by systems of hydrogen bonds which occur between the anions and cations. π–π interactions were observed between the HClQ⁺ cations in the structures of (I) and (IV).     

Pyrromethene–BF2 complexes as laser dyes:1.

Condensations between 3-X-2,4-dimethylpyrroles (X = H, CH₃, C₂H₅, and CO₂C₂H₅) and acyl chlorides gave derivatives of 3,5,3′,5′-tetramethylpyrromethene (isolated as their hydrochloride salts): 6-methyl, 6-ethyl, 4,4′,6-trimethyl, 4,4′-diethyl-6-methyl, and 4,4′-dicarboethoxy-6-ethyl derivatives for conversion on treatment with boron trifluoride to 1,3,5,7-tetramethylpyrromethene–BF₂ complex (TMP–BF₂) and its 8-methyl (PMP–BF₂), 8-ethyl, 2,6,8-trimethyl (HMP–BF₂),2,6,-diethyl-8-methyl (PMDEP–BF₂), and 2,6-dicarboethoxy-8-ethyl derivatives. Chlorosulfonation converted, 1,3,5,7,8-pentamethylpyrromethene–BF₂ complex to its 2,6-disulfonic acid isolated as the lithium, sodium (PMPDS–BF₂), potassium, rubidium, cesium, ammonium, and tetramethylammonium disulfonate salts and the methyl disulfonate ester. Sodium 1,3,5,7-tetramethyl-8-ethylpyrromethene-2,6-disulfonate–BF₂ complex was obtained from the 8-ethyl derivative of TMP–BF₂. Nitration and bromination converted PMP–BF₂ to its 2,6-dinitro-(PMDNP–BF₂) and 2,6-dibromo- derivatives. The time required for loss of fluorescence by irradiation from a sunlamp showed the following order for P–BF₂ compounds (10⁻³ to 10⁻⁴ M) in ethanol: PMPDS–BF₂, 7 weeks; PMP–BF₂, 5 days; PMDNP–BF₂, 72 h; HMP–BF₂, 70 h; and PMDEP–BF₂, 65 h. Under similar irradiation PMPDS–BF₂ in water lost fluorescence after 55 h. The dibromo derivative was inactive, but each of the other pyrromethene–BF₂ complexes under flashlamp excitation showed broadband laser activity in the region λ 530–580 nm. In methanol PMPDS–BF₂ was six times more resistant to degradation by flashlamp pulses than was observed for Rhodamine-6G (R-6G). An improvement (up to 66%) in the laser power efficiency of PMPDS–BF₂ (10⁻⁴ M in methanol) in the presence of caffeine (a filter for light <300 nm) was dependent on flashlamp pulse width (2.0 to 7.0 μsec).