An “Open Access”‐like mass spectrometric platform to fully utilize the simplicity of the manual open port sampling interface for rapid characterization of unprocessed samples by liquid introduction atmospheric pressure ionization mass spectrometry has been lacking. The in‐house developed integrated software with a simple, small and relatively low‐cost mass spectrometry system introduced here fills this void.
Methods
Software was developed to operate the mass spectrometer, to collect and process mass spectrometric data files, to build a database and to classify samples using such a database. These tasks were accomplished via the vendor‐provided software libraries. Sample classification based on spectral comparison utilized the spectral contrast angle method.
Results
Using the developed software platform near real‐time sample classification is exemplified using a series of commercially available blue ink rollerball pens and vegetable oils. In the case of the inks, full scan positive and negative ion ESI mass spectra were both used for database generation and sample classification. For the vegetable oils, full scan positive ion mode APCI mass spectra were recorded. The overall accuracy of the employed spectral contrast angle statistical model was 95.3% and 98% in case of the inks and oils, respectively, using leave‐one‐out cross‐validation.
Conclusions
This work illustrates that an open port sampling interface/mass spectrometer combination, with appropriate instrument control and data processing software, is a viable direct liquid extraction sampling and analysis system suitable for the non‐expert user and near real‐time sample classification via database matching. Published in 2016. This article is a U.S. Government work and is in the public domain in the USA.
The OPSI/MS analysis was carried out using Advion Expression® CMS.
Lieby Zborovsky, Alisa Smolyakova, Maria Baskin, Galia Maayan
Peptoids, N‐substituted glycine oligomers, are an important class of foldamers that can adopt polyproline‐type helices (PP‐I and PP‐II), given that the majority of their sequence consists of chiral, bulky side chains. Herein a new approach for the stabilization of a pure PP‐I‐like peptoid helix through metal coordination is introduced. A systematic spectroscopic study was performed on a series of peptoid heptamers bearing two 8‐hydroxyquinoline ligands at fixed positions, and a mixture of chiral benzyl and alkyl substituents in varied positions along the peptoid backbone. When the benzyl groups are located at the 3rd and 4th positions, the peptoid (7P6) gives upon Cu2+ binding a circular dichroism (CD) signal similar to that of a PP‐I helix. Exciton couplet CD spectroscopy and EPR spectroscopy, as well as modifications to the length of 7P6 and derivatization through acetylation provided insights into the unique folding of 7P6 upon Cu binding, showing that it is led by two competing driving forces, namely coordination geometry and sequence.
The MS analysis was carried out using Advion Expression® CMS.
Maria Baskin, Natalia Fridman, Monica Kosa,Galia Maayan
We describe the construction of synthetically challenging heteroleptic complexes by capitalizing on the solubility properties of their corresponding favored homoleptic complexes. We demonstrate that the formation of a heteroleptic Cu2+ complex based on 2,2′:6′,2′′-terpyridine (Terpy) and 8-hydroxyquinoline (HQ) is not possible due to the insolubility of (HQ)2Cu2+. Replacing HQ with 8-hydroxy-2-quinolinecarbonitrile (HQCN) enabled the solubility of (HQCN)2Cu2+ in acetonitrile, leading to the formation of the heteroleptic complex Terpy(HQCN)Cu2+, TQCu.Applying these conditions to the synthesis of the corresponding heteroleptic Co2+ complex resulted in TerpyCo2+(acetate)2, which is insoluble in acetonitrile. Upon changing the solvent to methanol, the carbonitrile group of HQCN was converted to carboxyimidate HQOMe yielding a heteroleptic complex Terpy(HQOMe)Co2+, TQ′Co. Using this method, we also generated the heteroleptic complex TQ′Ni and the polynuclear heteroleptic complex Q′4Q′′2Mn4 (Q′′ = HQO2Me). Detailed analysis of the complexes included characterization by X-ray diffraction, EPR, UV-Vis, high resolution ESI MS, DFT calculations and electrochemistry. X-ray analysis of TQCu revealed distorted square pyramidal geometry, while TQ′Co and TQ′Ni exhibit distorted octahedral geometry, which includes metal coordination via the carboxyimidate nitrogen site. Interestingly, Q′4Q′′2Mn4 was found to contain a [MnII4(μ3-O)2(μ2-O)4N10]2+ core, which adopts a distorted octahedral geometry, and two types of HQ chelators. Thus, Q′4Q′′2Mn4 is also heteroleptic even though it does not contain a Terpy ligand. Solution studies revealed that while TQCu is stable in solution, TQ′Co and TQ′Ni go through ligand exchange and are partially converted to their corresponding homoleptic complexes. Based on these data we could propose a mechanism for the formation of TQ′Co and TQ′Ni and show that TQ′Co can be prepared directly from Terpy and HQOMe.
The MS analysis was carried out using Advion Expression® CMS ESI.
CN-modified host materials, 9-(2-(9-phenyl-9H-carbazol-3-yl)phenyl)-9H-carbazole-3-carbonitrile (o-CzCN) and 9-(3-(9-phenyl-9H-carbazol-3-yl)phenyl)-9H-carbazole-3-carbonitrile (m-CzCN), which can improve the external quantum efficiency and lifetime of both blue phosphorescent and thermally activated delayed fluorescent (TADF) emitters were developed. A molecular design approach to stabilize the molecular structure and reduce the energy gap produced two high triplet energy host materials of o-CzCN and m-CzCN compatible with the phosphorescent and TADF emitters. The new host materials lowered operation voltage, increased quantum efficiency, and elongated lifetime of both phosphorescent and TADF devices.
The MS analysis was carried out using Advion Expression® CMS.
Negative polaron stabilizing host materials for blue phosphorescence organic light‐emitting diodes are synthesized by modifying carbazolylcarbazole with dibenzothiophene or 9‐phenylcarbazole. The host materials show high triplet energy above 2.95 eV and work as hole transport type hosts. Operational lifetime analysis of the blue devices with the two hosts demonstrates that the dibenzothiophene modified carbazolylcarbazole host functions better than the 9‐phenylcarbazole modified carbazolylcarbazole host. Improved negative polaron stability from bond dissociation energy calculation and single carrier aging test results is the main factor for the lifetime extension in the dibenzothiophene modified carbazolylcarbazole host based blue phosphorescent organic light‐emitting diodes.
The MS analysis was carried out using Advion Expression® CMS.
Claudia Schmidt, Bianka Karge, Rainer Misgeld, Aram Prokop, Mark Brönstrup,Ingo Ott
A series of gold(I) complexes with two N-heterocyclic carbene ligands (biscarbene gold complexes) were prepared and evaluated for their effects against cancer cells and pathogenic bacteria. Proliferation inhibition was observed in cancer cells and in Gram-positive bacteria, whereas Gram-negative bacteria were less sensitive towards the compounds. The protein binding and cellular uptake were quantified and the combined results indicated a strong correlation between cellular bioavailability and antiproliferative effects. The biscarbene gold complexes inhibited bacterial and mammalian TrxRs with low to moderate potency. However, based on the obtained structure–activity-relationships and the high cellular accumulation levels, TrxR inhibition can be considered as a relevant contributor to the cellular pharmacology of biscarbene gold(I) complexes.
The MS analysis was carried out using Advion Expression® CMS.
Damien Ertz, Ulrick Søchting, Alice Gadea, Maryvonne Charrier, Roar S. Poulsen
The new genus and species Ducatina umbilicata is described from Îles Crozet and Îles Kerguelen. This lichen is characterized by an umbilicate thallus with a black verrucose lower surface and a greyish to dark olivaceous smooth upper surface having large verrucae, large semiimmersed cephalodia, semi-immersed apothecia with a prominent thalline margin, simple, mainly ellipsoid ascospores of 23–42Å~12–25 μm and the presence of unknown chemical compounds. Phylogenetic analyses using nuLSU and mtSSU sequences place Ducatina in the Trapeliaceae (Baeomycetales). The new taxon is closely related to Orceolina antarctica and O. kerguelensis, two other lichens endemic to these subantarctic islands, differing by its morphology and the lack of chemical compounds. Ducatina is the only genus in the Trapeliaceae to develop a large umbilicate thallus.
The HPLC/MS analysis was carried out using Advion Expression® CMS ESI.
The design of a bioreversibly protected lipophilic sugar nucleotide as a potential membrane‐permeable precursor of adenosine diphosphate ribose (ADPR) is described. ADPR is the most potent activator of the transient receptor potential melastatin 2 (TRPM2) ion channel. Membrane‐permeable, lipophilic derivatives of ADPR are of great interest as tools for study of the mechanism of TRPM2. The approach described here was based on our recently disclosed “DiPPro” and “TriPPPro” prodrug approaches developed for the intracellular delivery of nucleotides. A lipophilic, bioreversibly masked ADPR analogue containing an enzymatically cleavable 4‐pentanoyloxybenzyl (PB) mask at the phosphate moiety next to the 5′‐position of adenosine, together with O‐acetyl groups, was prepared in high yields. Chemical and enzymatic hydrolysis studies in phosphate buffer (pH 7.3) were performed to assess chemical stability and possible (selective) enzymatic demasking of the ADPR analogue. HPLC‐MS revealed that the PB group was readily cleaved enzymatically. In addition, the formation of partially deacetylated ADPR compounds and also of fully unprotected ADPR was observed.
The MS analysis was carried out using Advion Expression® CMS.
J. A. H. Inkster, S. Zhang, V. Akurathi, A. Belanger, S. Dubey, S. T. Treves, A. B. Packard
New chemical and radiochemical syntheses are described for the preparation of [18F]Rho6G-DEG-F, an 18F-labeled analogue of the fluorescent dye rhodamine 6G, which has shown promise as myocardidal perfusion imaging agent. Tosylated precursors of [18F]Rho6G-DEG-F amenable to 18F-labeling were obtained either through a two-step synthesis from rhodamine 6G lactone (33% yield), or in one step from rhodamine 575 (64% yield), then purified by preparative C18 chromatography. Manual synthesis of [18F]Rho6G-DEG-F was achieved in a single radiochemical step from either the tosylate salt or the tosylate/formate double salt in DMSO under standard nucleophillic aliphatic 18F-fluorination conditions (K[18F]F/K2CO3/Kryptofix 2.2.2.). Incorporation of the [18F]F− was found to be satisfactory (≥34% by TLC), despite the protic character of the precursor molecules. [18F]Rho6G-DEG-F was manually synthesized in final decay-corrected radiochemical yields of 11–26% (tosylate salt) and 9–21% (tosylate/formate double salt). The protocol was transferred to an automated synthesis unit, where the product was obtained in 3–9% radiochemical yield (n = 3) decay corrected to start-of-synthesis, >99% radiochemical purity, and a molar activity of 122–267 GBq μmol−1 (3.3–7.2 Ci μmol−1).
The MS analysis was carried out using Advion Expression® CMS.
CN-modified host materials, 9-(2-(9-phenyl-9H-carbazol-3-yl)phenyl)-9H-carbazole-3-carbonitrile (o-CzCN) and 9-(3-(9-phenyl-9H-carbazol-3-yl)phenyl)-9H-carbazole-3-carbonitrile (m-CzCN), which can improve the external quantum efficiency and lifetime of both blue phosphorescent and thermally activated delayed fluorescent (TADF) emitters were developed. A molecular design approach to stabilize the molecular structure and reduce the energy gap produced two high triplet energy host materials of o-CzCN and m-CzCN compatible with the phosphorescent and TADF emitters. The new host materials lowered operation voltage, increased quantum efficiency, and elongated lifetime of both phosphorescent and TADF devices.
