No abstract

Collision cross section (CCS, Ω) values determined by ion mobility mass spectrometry (IM-MS) provide the study of ion shape in the gas phase and use of these as further identification criteria in analytical approaches. Databases of CCS values for a variety of molecules determined by different instrument types are available. In this study, the comparability of CCS values determined by a drift tube ion mobility mass spectrometer (DTIM-MS) and a traveling wave ion mobility mass spectrometer (TWIM-MS) was investigated to test if a common database could be used across IM techniques. A total of 124 substances were measured with both systems and CCS values of [M + H] and [M + Na] adducts were compared. Deviations <1% were found for most substances, but some compounds show deviations up to 6.2%, which indicate that CCS databases cannot be used without care independently from the instrument type. Additionally, it was found that for several molecules [2M + Na] ions were formed during electrospray ionization, whereas a part of them disintegrates to [M + Na] ions after passing through the drift tube and before reaching the TOF region, resulting in two signals in their drift spectrum for the [M + Na] adduct. Finally, the impact of different LC-IM-MS settings (solvent composition, solvent flow rate, desolvation temperature, and desolvation gas flow rate) were investigated to test whether they have an influence on the CCS values or not. The results showed that these conditions have no significant impact. Only for karbutilate changes in the drift spectrum could be observed with different solvent types and flow rates using the DTIM-MS system, which could be caused by the protonation at different sites in the molecule.

The anthropogenic entry of organic micropollutants into the aquatic environment leads to a potential risk for drinking water resources and the drinking water itself. Therefore, sensitive screening analysis methods are needed to monitor the raw and drinking water quality continuously. Non-target screening analysis has been shown to allow for a more comprehensive investigation of drinking water processes compared to target analysis alone. However, non-target screening is challenging due to the many features that can be detected. Thus, data processing techniques to reduce the high number of features are necessary, and prioritization techniques are important to find the features of interest for identification, as identification of unknown substances is challenging as well. In this study, a drinking water production process, where drinking water is supplied by a water reservoir, was investigated. Since the water reservoir provides surface water, which is anthropogenically influenced by wastewater treatment plant (WWTP) effluents, substances originating from WWTP effluents and reaching the drinking water were investigated, because this indicates that they cannot be removed by the drinking water production process. For this purpose, ultra-performance liquid chromatography coupled with an ion-mobility high-resolution mass spectrometer (UPLC-IM-HRMS) was used in a combined approach including target, suspect and non-target screening analysis to identify known and unknown substances. Additionally, the role of ion-mobility-derived collision cross sections (CCS) in identification is discussed. To that end, six samples (two WWTP effluent samples, a surface water sample that received the effluents, a raw water sample from a downstream water reservoir, a process sample and the drinking water) were analyzed. Positive findings for a total of 60 substances in at least one sample were obtained through quantitative screening. Sixty-five percent (15 out of 23) of the identified substances in the drinking water sample were pharmaceuticals and transformation products of pharmaceuticals. Using suspect screening, further 33 substances were tentatively identified in one or more samples, where for 19 of these substances, CCS values could be compared with CCS values from the literature, which supported the tentative identification. Eight substances were identified by reference standards. In the non-target screening, a total of ten features detected in all six samples were prioritized, whereby metoprolol acid/atenolol acid (a transformation product of the two β-blockers metoprolol and atenolol) and 1,3-benzothiazol-2-sulfonic acid (a transformation product of the vulcanization accelerator 2-mercaptobenzothiazole) were identified with reference standards. Overall, this study demonstrates the added value of a comprehensive water monitoring approach based on UPLC-IM-HRMS analysis. Graphical abstract

A reliable quantification by LC-ESI-MS/MS as the most suitable analytical method for polar substances in the aquatic environment is usually hampered by matrix effects from co-eluting compounds, which are unavoidably present in environmental samples. The standard addition method (SAM) is the most appropriate method to compensate matrix effects. However, when performed manually, this method is too labour- and time-intensive for routine analysis. In the present work, a fully automated SAM using a multi-purpose sample manager "Open Architecture UPLC®-MS/MS" (ultra-performance liquid chromatography tandem mass spectrometry) was developed for the sensitive and reliable determination of 29 polar pesticide metabolites in environmental samples. A four-point SAM was conducted parallel to direct-injection UPLC-ESI-MS/MS determination that was followed by a work flow to calculate the analyte concentrations including monitoring of required quality criteria. Several parameters regarding the SAM, chromatography and mass spectrometry conditions were optimised in order to obtain a fast as well as reliable analytical method. The matrix effects were examined by comparison of the SAM with an external calibration method. The accuracy of the SAM was investigated by recovery tests in samples of different catchment areas. The method detection limit was estimated to be between 1 and 10 ng/L for all metabolites by direct injection of a 10-μL sample. The relative standard deviation values were between 2 and 10% at the end of calibration range (30 ng/L). About 200 samples from different water bodies were examined with this method in the Rhine and Ruhr region of North Rhine-Westphalia (Germany). Approximately 94% of the analysed samples contained measurable amounts of metabolites. For most metabolites, low concentrations ≤0.10 μg/L were determined. Only for three metabolites were the concentrations in ground water significantly higher (up to 20 μg/L). In none of the examined drinking water samples were the health-related indication values (between 1 and 3 μg/L) for non-relevant metabolites exceeded.

Heating Re2(CO)s(ax-L)2 (1) [L = P(C&5)3] in xylene solution in a sealed glass tube at 180-230 OC gives six products of two (CO)&,L, (m = 1, ax-L, n = 0, 4; m = n = 1, ax-L, 5; m = 1, eq-L, n = 1, ax-L, 6 m = 0, n = 2, ax-L, 7). At 160 "C only 2 and 3 are observed. The complex Re2(CO)s(r-H)(r-P(C6H5)2) (8) is obtained by thermolysis of Re,(CO),(ax-L) (9) in xylene solution at 180 OC. Thermolysis of 2 in decalin solution at 240 "C leads to Re3(CO)&-P(C6H5)2)3 (10). 'H and ,'P NMR data have been measured for the newly synthesized compounds. The molecular structures of 2,4, and 10 have been determined from X-ray data collected on an automated diffractometer with monochromatized Mo Ka radiation. Compounds 2 and 4 crystallize in the monoclinic space group P2Jn (No. 14), and 10 crystallizes in P 2 J a (No. 14), with 2 = 4: 2, a = 13.431 (9) A, b = 11.804 (5) A, c = 23.072 (12) A, @ = 102.78 (6)"; 4, a = 16.800 (2) A, b = 12.077 (3) A, c = 23.048 (3) A, @ = 92.82 (1)O; 10, a = 11.670 (3) A, b = 23.151 (14) A, c = 16.327 (3) A, @ = 90.08 (3)". The molecular structure of the diamagnetic compound 2 contains two octahedrally coordinated rhenium atoms with a hydrido-and diphenylphosphido-bridged Re-Re bond (Re-Re = 3.152 (1) A). The p-H position could not be evaluated from a Fourier map. Therefore, the presence of the monohydride compound was shown by the results of 'H high-field NMR measurements. The eq-L ligand in 2 is trans-positioned to the p-P(C,H,), group. The molecular structure of the secondary metalation product 4 possesses two rhenium atoms, each with an essentially octahedral arrangement of the ligands. One rhenium atom is coordinated by four carbonyl groups while the other is coordinated by three carbonyl groups and a triphenylphosphine. The two rhenium atoms are bridged by a quadridentate ligand that is bidentate to each metal atom. The molecule has an extended planar tricyclic ring system that includes the bridging ligand and both metal atoms. A comparison of its bond parameters with those of related rhenium and manganese compounds is given. The molecular structure of 10 shows as a central fragment a three-membered ring of rhenium atoms [average Re-Re = 2.914 (4) A] edged-bridged by diphenylphosphido groups. Each rhenium coordination sphere contains, besides the two trans-positioned p-P ligand atoms, three additional CO groups having a meridional ligand arrangement.types: first, Re2(CO)8,L.(r-H)(p-P(C,H,)2) (n = 1, eq-L, 2; n 2, eq-L, 3); second, (C6H5)2PC6H3(C=O)Re(co)~mLmRe-