| 11. |
- Liigand, Piia, et al.
(author)
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30 Years of research on ESI/MS response : Trends, contradictions and applications
- 2021
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In: Analytica Chimica Acta. - : Elsevier BV. - 0003-2670 .- 1873-4324. ; 1152
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Journal article (peer-reviewed)abstract
- The variation of ionization efficiency for different compounds has puzzled researchers since the invention of the electrospray mass spectrometry (ESI/MS). Ionization depends on the properties of the compound, eluent, matrix, and instrument. Despite significant research, some aspects have remained unclear. For example, research groups have reached contradicting conclusions regarding the ionization processes. One of the best-known is the significance of the logP value for predicting the ionization efficiency. In this tutorial review, we analyse the methodology used for ionization efficiency measurements as well as the most important trends observed in the data. Additionally, we give suggestions regarding the measurement methodology and modelling strategies to yield meaningful and consistent ionization efficiency data. Finally, we have collected a wide range of ionization efficiency values from the literature and evaluated the consistency of these data. We also make this collection available for everyone for downloading as well as for uploading additional and new ionization efficiency data. We hope this GitHub based ionization efficiency repository will allow a joined community effort to collect and unify the current knowledge about the ionization processes.
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| 12. |
- Liu, Chaolong, et al.
(author)
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A Ruthenium(II) complex-based probe for colorimetric and luminescent detection and imaging of hydrogen sulfide in living cells and organisms
- 2021
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In: Analytica Chimica Acta. - : Elsevier BV. - 0003-2670 .- 1873-4324. ; 1145, s. 114-123
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Journal article (peer-reviewed)abstract
- The development of reliable bioanalytical probes for sensitive and specific detection of hydrogen sulfide (H2S) plays important role for better understanding the roles of this biomolecule in living cells and or-ganisms. Taking advantages of unique photophysical properties of ruthenium(II) (Ru(II)) complex, this work presents the development of a responsive Ru(II) complex probe, Ru-PNBD, for colorimetric and luminescent analysis of H2S in living cells and organisms. In aqueous solution, Ru-PNBD is yellow color and non-luminescent because of the photoinduced electron transfer (PET) process from Ru(II) complex luminophore to NBD moiety. The H2S-triggered specific nucleophilic substitution reaction with Ru-PNBD cleaves the NBD moiety to form pink NBD-SH and highly luminescent Ru-PH. The color of the solution thus changes from yellow to pink for colorimetric analysis and the emission intensity is about 65-fold increased for luminescent analysis. Ru-PNBD has high sensitivity and selectivity for H2S detection, low cytotoxicity and good permeability to cell membrane, which allow the application of this probe for H2S imaging in living cells, Daphnia magna, and larval zebrafish. Collectively, this work provides a useful tool for H2S analysis and expands the scope of transition metal complex probes.
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| 13. |
- Marrubini, Giorgio, et al.
(author)
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Experimental designs for solid-phase microextraction method development in bioanalysis : A review
- 2020
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In: Analytica Chimica Acta. - : Elsevier. - 0003-2670 .- 1873-4324. ; 1119, s. 77-100
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Research review (peer-reviewed)abstract
- This review is an update of a previous review in 2009 and covers publications from 2009 to 2019. The review focuses on experimental design, referred to as the design of experiments (DoE), used in developing bioanalytical solid-phase microextraction (SPME) methods. Characteristics of different SPME approaches are illustrated and critically discussed. The literature selection evidences that two-level full factorial designs, with a limited number of factors (<5), are most frequently used for preliminary factors screening. When applying the response surface methodology for the quantitative assessment of factorial effects, few quadratic models were used. The most popular were the rotatable central composite and Box-Benkhen designs. Models including more than four factors, such as fractional factorial designs (including the Plackett-Burman and Taguchi designs), were rarely used. Definitive screening and D-Optimal designs were not reported anywhere in the literature selection. When examining the diagnostic criteria used to evaluate different model's quality and validity, it was apparent the researchers relied heavily on commercial software for experimental design, analysis, and reporting of the results.
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| 14. |
- Mullin, L., et al.
(author)
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Liquid chromatography-ion mobility-high resolution mass spectrometry for analysis of pollutants in indoor dust : Identification and predictive capabilities
- 2020
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In: Analytica Chimica Acta. - : Elsevier. - 0003-2670 .- 1873-4324. ; 1125, s. 29-40
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Journal article (peer-reviewed)abstract
- Dust analysis provides a means to assess the degree of exposure of humans in an indoor environment to various contaminant classes such as flame retardants, pesticides and others. There is increasing interest in non-targeted acquisitions using high resolution mass spectrometry (HRMS) to better capture the contaminant profile. However, these studies are confronted with the challenge of assessing confidence in proposed identifications, particularly when authentic standards are not available. Here, we demonstrate the analysis of dust extracts representing various indoor environments (industrial e-waste processing and domestic) for high-abundance environmental contaminants using a data-independent LC-HRMS approach, incorporating ion mobility spectrometry (IMS) to provide additional characterization capability for the complex samples. Twenty-nine xenobiotic compound identifications were made based on both targeted and non-targeted processing approaches using accurate mass precursor and product ion measurement combined with an ion mobility derived collision-cross section (TWCCSN2) determination. Characterization of the repeatability of TWCCSN2 value measurements and their average relative error to compared authentic standards of 0.38% were consistent with various published studies and represent a robust measurement property. TWCCSN2 values were particularly useful in cases where confirmation after the initial dust analysis was performed using a different chromatographic method, due to the gas-phase measurement being unaffected by such changes. Observed compound TWCCSN2 values were then compared to predicted CCSN2 values obtained using two different machine-learning based predictive techniques. Results from one of the predictive programs indicates a promising avenue for use of these models for supporting compound identification in non-targeted analyses.
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| 15. |
- Mäkelä, Mikko, et al.
(author)
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Hyperspectral near infrared image calibration and regression
- 2020
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In: Analytica Chimica Acta. - : Elsevier BV. - 0003-2670 .- 1873-4324. ; 1105, s. 56-63
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Journal article (peer-reviewed)abstract
- Reference materials are used in diffuse reflectance imaging for transforming the digitized camera signal into reflectance and absorbance units for subsequent interpretation. Traditional white and dark reference signals are generally used for calculating reflectance or absorbance, but these can be supplemented with additional reflectance targets to improve the accuracy of reflectance transformations. In this work we provide an overview of hyperspectral image regression and assess the effects of reflectance calibration on image interpretation using partial least squares regression. Linear and quadratic reflectance transformations based on additional reflectance targets decrease average measurement errors and make it easier to estimate model pseudorank during image regression. The lowest measurement and prediction errors were obtained with the column and wavelength specific quadratic transformations which retained the spatial information provided by the line-scanning instrument and reduced errors in the predicted concentration maps. (C) 2020 Elsevier B.V. All rights reserved.
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| 16. |
- Ross, Georgina M. S., et al.
(author)
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Interconnectable solid-liquid protein extraction unit and chip-based dilution for multiplexed consumer immunodiagnostics
- 2020
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In: Analytica Chimica Acta. - : ELSEVIER. - 0003-2670 .- 1873-4324. ; 1140, s. 190-198
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Journal article (peer-reviewed)abstract
- While consumer-focused food analysis is upcoming, the need for multiple sample preparation and handling steps is limiting. On-site and consumer-friendly analysis paradoxically still requires laboratory based and skill-intensive sample preparation methods. Here, we present a compact, inexpensive, and novel prototype immunosensor combining sample preparation and on-chip reagent storage for multiplex allergen lateral flow immunosensing. Our comprehensive approach paves the way for personalized consumer diagnostics. The prototype allows for handheld solid-liquid extraction, pipette-free on-chip dilution, and adjustment of sample concentrations into the appropriate assay dynamic working range. The disposable and interconnectable homogenizer unit allows for the extraction and 3D-sieve based filtration of allergenic proteins from solid bakery products in 1 min. The homogenizer interconnects with a 3D-printed unibody lab-on-a-chip (ULOC) microdevice, which is used to deliver precise volumes of sample extract to a reagent reservoir. The reagent reservoir is implemented for on-chip storage of carbon nanoparticle labeled antibodies and running buffer for dilution. The handheld prototype allows for total homogenization of solid samples, solid-liquid protein extraction, 3D-printed sieve based filtration, ULOCenabled dilution, mixing, transport, and smartphone-based detection of hazelnut and peanut allergens in solid bakery products with limited operational complexity. The multiplex lateral flow immunoassay (LFIA) detects allergens as low as 0.1 ppm in real bakery products, and the system is already consumer operable, demonstrating its potential for future citizen science approaches. The designed system is suitable for a wide range of analytical applications outside of food safety, provided an LFIA is available. (C) 2020 Elsevier B.V. All rights reserved.
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| 17. |
- Souihi, Amina, et al.
(author)
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Mobile phase and column chemistry selection for high sensitivity non-targeted LC/ESI/HRMS screening of water
- 2023
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In: Analytica Chimica Acta. - 0003-2670 .- 1873-4324. ; 1274
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Journal article (peer-reviewed)abstract
- Systematic selection of mobile phase and column chemistry type can be critical for achieving optimal chromatographic separation, high sensitivity, and low detection limits in liquid chromatography electrospray high resolution mass spectrometry (LC/MS). However, the selection process is challenging for non-targeted screening where the compounds of interest are not preselected nor available for method optimization. To provide general guidance, twenty different mobile phase compositions and four columns were compared for the analysis of 78 compounds with a wide range of physicochemical properties (logP range from -1.46 to 5.48), and analyte sensitivity was compared between methods. The pH, additive type, column, and organic modifier had significant effects on the analyte response factors, and acidic mobile phases (e.g. 0.1% formic acid) yielded highest sensitivity. In some cases, the effect was attributable to the difference in organic modifier content at the time of elution, depending on the mobile phase and column chemistry. Based on these findings, 0.1% formic acid, 0.1% ammonia and 5.0 mM ammonium fluoride were further evaluated for their performance in non-targeted LC/ESI/ HRMS analysis of wastewater treatment plan influent and effluent, using a data dependent MS2 acquisition and two different data processing workflows (MS-DIAL, patRoon 2.1) to compare number of detected features and sensitivity. Both data-processing workflows indicated that 0.1% formic acid yielded the highest number of features in full scan spectrum (MS1), as well as the highest number of features that triggered fragmentation spectra (MS2) when dynamic exclusion was used.
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| 18. |
- Thai, Nguyen Xuan, et al.
(author)
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Multi gas sensors using one nanomaterial, temperature gradient, and machine learning algorithms for discrimination of gases and their concentration
- 2020
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In: Analytica Chimica Acta. - : ELSEVIER. - 0003-2670 .- 1873-4324. ; 1124, s. 85-93
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Journal article (peer-reviewed)abstract
- In this work, four identical micro sensors on the same chip with noble metal decorated tin oxide nanowires as gas sensing material were located at different distances from an integrated heater to work at different temperatures. Their responses are combined in highly informative 4D points that can qualitatively (gas recognition) and quantitatively (concentration estimate) discriminate all the tested gases. Two identical chips were fabricated with tin oxide (SnO2) nanowires decorated with different metal nanoparticles: one decorated with Ag nanoparticles and one with Pt nanoparticles. Support Vector Machine was used as the "brain" of the sensing system. The results show that the systems using these multisensor chips were capable of achieving perfect classification (100%) and good estimation of the concentration of tested gases (errors in the range 8-28%). The Ag decorated sensors did not have a preferential gas, while Pt decorated sensors showed a lower error towards acetone, hydrogen and ammonia. Combination of the two sensor chips improved the overall estimation of gas concentrations, but the individual sensor chips were better for some specific target gases. (C) 2020 Elsevier B.V. All rights reserved.
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| 19. |
- Ugolini, Valentina, et al.
(author)
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Novel, alternative analytical methodology for determination of antimicrobial chemicals in aquatic environments and public use assessment: Extraction sorbent, microbiological sensitivity, stability, and applicability
- 2024
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In: Analytica Chimica Acta. - 0003-2670 .- 1873-4324. ; 1286
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Journal article (peer-reviewed)abstract
- Background: Assessing antimicrobial chemicals from wastewater source to recipient water systems is crucial in planning effective, policy-related interventions for antimicrobial resistance (AMR) risk mitigation. However, the capability of related analytical methods for AMR assessment has not been explored previously. There is also a lack of knowledge on the effectiveness of alternative extraction sorbents with ion-exchange functions, and little information on chemical stability from sampling to analysis as well as preservative options. Hence, our study aims to address the clear need for advanced, broad-range and microbiologically-sensitive methodologies, paired with thorough stability assessments.Results: Oasis (R) WCX ion-exchange was for the first time employed in solid-phase extraction (SPE) for antibacterials, antifungals, antivirals and human metabolites in various water matrices. Analysis was performed using liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) on a biphenyl analytical column. The optimized and validated method provided satisfactory accuracy, precision, and recovery for 53 compounds via LC-MS/MS direct injection and for up to 35 compounds via SPE-LC-MS/MS. Method quantification limits (MQLs) were determined in groundwater (0.33-54 ng L-1), surface water (0.53-75 ng L-1), effluent wastewater (2.5-470 ng L-1), and influent wastewater (11-650 ng L-1). As a novel approach, MQLs were compared with minimum inhibitory concentrations, to confirm our method's microbiological sensitivity for studying AMR. Stability assessment revealed that most compounds remained stable in standard solution at-80 degrees C for six months, in various waters at-20 degrees C for eight weeks, and during 24-h sampling at 4 degrees C. Sodium azide was a better preservative than sodium metabisulfite.Significance: Our study is an added value to the analytical methodology for water measurements of antimicrobial chemicals, in which it provides a novel, alternative method that is robust and overall more sensitive than others using generic Oasis (R) HLB sorbents and C18 analytical columns in SPE-LC-MS/MS. Also, the comprehensive data on antimicrobial stability helps reduce methodological uncertainty for future studies. Our method shows sufficient microbiologically-sensitivity and thus is suitable for future (inter)national regulatory water monitoring of AMR.
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| 20. |
- Xiao, Chi, et al.
(author)
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Print-and-stick unibody microfluidics coupled surface plasmon resonance (SPR) chip for smartphone imaging SPR (Smart-iSRP)
- 2022
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In: Analytica Chimica Acta. - : Elsevier. - 0003-2670 .- 1873-4324. ; 1201
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Journal article (peer-reviewed)abstract
- The design of a smartphone imaging surface plasmon resonance (Smart-iSPR) system integrated with an affordable 3D-printed microfluidic SPR chip fabricated via a facile manufacturing approach could pave the way towards the development of miniaturized and integrated smartphone iSPR biosensors for emerging point-of-use applications. Conventional smartphone-based SPR systems using soft photolithography for the fabrication of microfluidics SPR chips are costly, labour-intensive and required a specially-equipped light-controlled environment, that is inadequate and mismatched with the consumer-based smartphone detection platform. Herein, we report the design, fabrication and testing of an innovative print-and-stick unibody microfluidics coupled SPR chip for smartphone iSPR. The 3Dprinted microfluidics (~V0.006) is assembled via an aptly-sized adhesive tape with the gold SPR sensing surface. Such a simple integrated microfluidic SPR chip with the print-and-stick configuration has a high resistance to fluid leakages at the channel-to-sensor interface with pressure up to 66.9 Pa and the tubingto-inset interfaces with pressure up to 86.9 Pa. The smartphone iSPR platform weighs 138 g and with a dimension of around 70 x 60 x 40 mm3, and its performance was characterized using a standard Biacore (R) 02-microglobulin calibration kit. The sensorgrams obtained by the smartphone iSPR show all the typical characteristics for surface functionalization, association and dissociation events. The smartphone iSPR responds linearly to 02-microglobulin within the range of 10-200 nM (R2 = 0.986) with a limit-ofdetection (LOD) of 1.5 nM. Given the miniaturized feature and simple camera-based imaging smartphone iSPR, the analytical performance is satisfactory when compared with the analytical dynamic range of 2 -32 nM described in the Biacore (R) protocol.(c) 2022 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
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