Search results for "Quadrupole"
showing 10 items of 460 documents
Homoleptic iron(II) complexes with the ionogenic ligand 6,6′-Bis(1H-tetrazol-5-yl)-2,2′-bipyridine: spin crossover behavior in a singular 2D spin cro…
2015
Deprotonation of the ionogenic tetradentate ligand 6,6′-bis(1H-tetrazol-5-yl)-2,2′-bipyridine [H2bipy(ttr)2] in the presence of FeII in solution has afforded an anionic mononuclear complex and a neutral two-dimensional coordination polymer formulated as, respectively, NEt3H{Fe[bipy(ttr)2][Hbipy(ttr)2]}·3MeOH (1) and {Fe[bipy(ttr)2]}n (2). The anions [Hbipy(ttr)2]− and [bipy(ttr)2]2– embrace the FeII centers defining discrete molecular units 1 with the FeII ion lying in a distorted bisdisphenoid dodecahedron, a rare example of octacoordination in the coordination environment of this cation. The magnetic behavior of 1 shows that the FeII is high-spin, and its Mössbauer spectrum is characteriz…
Direct Peel Monitoring of Xenobiotics in Fruit by Direct Analysis in Real Time Coupled to a Linear Quadrupole Ion Trap–Orbitrap Mass Spectrometer
2013
Study of xenobiotics present in fruit peel by exposing it (without any pretreatment) to direct analysis in real time coupled to a high-resolution orbitrap mass spectrometer (DART-HRMS) is reported for the first time. Variables such as DART gas heater temperature and pressure, source-to-MS distance, and sample velocity are investigated. The analysis of one sample by DART-MS lasts ca. 1 min, and the benefits of both high-resolution and tandem mass spectrometry to elucidate nontarget or unknown compounds are combined. Identification of postharvest fungicides, antioxidants, and sugars in fruit peel is performed in the positive ion mode. A possible elemental formula is suggested for marker compo…
Organotin(IV) complexes with tetraethyl ethylene- and propylene-diphosphonates
1995
The series of organotin halide complexes with tetraethyl ethylene- and propylene-diphosphonates R n SnX 4-n .L [n=0, X=Cl; n=1, R=Me, X=Cl, Br; n=1, R=Ph, X=Cl; n=2 R=Me, Et, Bu, X=Cl, Br; n=2, R=Ph, X=Cl; L=(EtO) 2 P(O)CH 2 CHR'P(O)(OEt) 2 , R'=H, Me] were synthesized and characterized by means of NMR and Mossbauer spectroscopy. The crystal structure of the complex of diphenyltin dichloride with propylenediphosphonate was determined. The complex consists of polymer chains with bridging bidentate ligands and an octahedral tin environment containing two types of phosphoryl fragments. All of the R 2 SnX 2 adducts have trans-R 2 SnX 4 geometries of tin coordination octahedra according to the q…
Characterization of complexes formed between [Me2Sn(IV)]2+ and carboxymethylcelluloses.
2006
Complexes formed between carboxymethylcellulose (CMC) and the [Me(2)Sn(IV)]2+ cation have been prepared in the solid state and characterized by FTIR and Mossbauer spectroscopy. The complexes contained CMC with varying molar weight and degree of carboxylation, and the complexes were isolated both from acidic and from neutral solutions at varying metal-to-ligand ratios. The characteristic vibration bands of the ligands were identified from their pH-dependent FTIR spectra. In the organotin(IV) complexes obtained at pH approximately 2, the -COO- moieties were found to be coordinated in a monodentate manner, and the band characteristic of the protonated (unbound) -COO- group(s) was also identifi…
Organometallic complexes with biological molecules II. Synthesis, solid-state characterization andin vivo Cytotoxicity of Diorganotin(IV)chloro and T…
1994
Several new diorganotin(IV)chloro and triorganotin(IV)chloro penicillin G derivatives have been prepared. The isolated compounds showed 1:1 stoichiometry, with formulae R2SnClpenG and R3SnClpenGNa, respectively (penG− = penicillin G− = 4- thia - 1 - azabicyclo[3.2.0]heptane-2-carboxylate, 3,3-dimethyl-7-oxo-6-(2-phenylacet-amido) anion; R = Me, Bu, Ph). The coordination environment around the the tin(IV) atom, in all of the complexes, was trigonal bipyramidal. Penicillin G behaved as a monoanionic, bismonodentate ligand in R2SnClpenG through the β-lactamic carbonyl and unidentate ester-type carboxylate anion, and as unidentate through the β-lactamic carbonyl in R3SnClpenGNa, as inferred on …
Structural characterization of triorganotin(IV) complexes with sodium fusidate and DFT calculations
2010
Abstract Three new complexes of the steroid sodium fusidate (sodium 2-[(1 S ,2 S ,5 R ,6 S ,7 S ,10 S ,11 S ,13 S , 14 Z ,15 R ,17 R )-13-(acetyloxy)-5,17-dihydroxy-2,6,10,11-tetramethyl tetracyclo[8.7.0.0 2,7 .0 11,15 ] heptadecan-14-ylidene]-6-methylhept-5-enoate = (NaFusidate, Na FA )]), with triorganotin(IV) moieties have been prepared and investigated by conventional techniques as FTIR, Mossbauer, ESI-MS and NMR spectroscopy. The isolated compounds showed stoichiometries organotin(IV)/fusidate 1/1, R 3 Sn(IV) FA (R = Me, FA1 ; Bu, FA2 ; Ph, FA3 ). The ligand coordination sites were determined by FTIR spectroscopic measurements. In the complexes, the carboxylate group of the fusidate li…
Determination of fungicide residues in fruits and vegetables by liquid chromatography–atmospheric pressure chemical ionization mass spectrometry
2002
Abstract A liquid chromatography (LC) method for the quantitative determination of five fungicide residues (dichloran, flutriafol, o -phenylphenol, prochloraz and tolclofos methyl) in oranges, lemons, bananas, peppers, chards and onions is described. The residues were extracted by matrix solid-phase dispersion (MSPD) using C 8 . Quantitative analysis was performed by isocratic LC coupled to quadrupole mass spectrometer using atmospheric pressure chemical ionization in the negative ionization mode. The limit of quantification was 0.01 mg kg −1 for flutriafol, o -phenylphenol and dichloran, and 0.1 mg kg −1 for prochloraz and tolclofos methyl. The MSPD method is also suitable for LC–UV analys…
Multiple-stage mass spectrometric analysis of six pesticides in oranges by liquid chromatography–atmospheric pressure chemical ionization–ion trap ma…
2004
Abstract Six pesticides were determined by liquid chromatography (LC) with positive ion (PI) atmospheric pressure chemical ionization quadrupole ion-trap tandem mass spectrometry (APCI–MS–MS). Ion fragmentation was studied by MS, MS 2 and MS 3 . Fragmentation of the pesticides produced ions formed by various losses from the side-chains and through heterocyclic ring opening, but without any common fragmentation pathway. Multiple reaction monitoring (MRM) of MS, MS 2 and MS 3 was used to identify and quantify the pesticides. The samples were extracted with ethyl acetate and dried over anhydrous sodium sulfate. Comparison of the three MS modes showed that MS 3 is slightly less sensitive but mu…
Improvement of the detection limit for determination of 129I in sediments by quadrupole inductively coupled plasma mass spectrometer with collision c…
2004
The previously developed sample introduction device for the hot extraction of iodine from environmental samples (soils or sediments) and on-line introduction of analyte via the gas phase in quadrupole inductively coupled plasma mass spectrometry with hexapole collision cell (ICP-CC-QMS) was equipped with a cooling finger, which allowed intermediate iodine enrichment and improved the detection limits for I-129 down to 0.4 pg g(-1) without any additional sample preparation. A mixture of oxygen and helium as reaction gases in the hexapole collision cell was used for reducing the disturbing background intensity of Xe-129(+). Oxygen was also used as the carrier gas for iodine thermal desorption …
Determination of amitraz and its transformation products in pears by ethyl acetate extraction and liquid chromatography-tandem mass spectrometry.
2008
A method has been developed for identification and quantification of the acaricide amitraz and its transformation products, 2,4-dimethylaniline (DMA), 2,4-dimethylformamidine (DMF) and N-2,4-dimethylphenyl-N-methylformamidine (DMPF) in pears. The analytes were extracted using ethyl acetate and anhydrous sodium sulphate. Analysis was performed by liquid chromatography-electrospray tandem mass spectrometry (LC-ESI-MS/MS) in the positive ion mode using a triple quadrupole (QqQ) instrument. Two precursor-product ion transitions were monitored for each compound in the selected reaction monitoring (SRM) mode. The method was validated with pears taken from the orchard before the amitraz treatment …