Use of high‐pH (basic/alkaline) mobile phases for LC–MS or LC–MS/MS bioanalysis

Tan, Aimin; Fanaras, John C.

doi:10.1002/bmc.4409

Cited by 30 publications

(14 citation statements)

References 80 publications

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“…To improve the detection of the low abundance peptides and enhance the depth of the proteome, different off-line fractionation methods have been used to reduce the complexity of peptide mixtures in samples prior to LC-MS/MS analysis. Methods including two-dimensional gel electrophoresis 20 , 21 , strong cation exchange (SCX), electrostatic repulsion-hydrophilic interaction chromatography (ERLIC) 22 , and high-pH reversed-phase chromatography 23 , 24 are used to increase peptide identification by separating peptides in an orthogonal dimension 25 . With the advancement of multiplex isobaric tandem mass tags (TMT), off-line fractionation and high-resolution MS, proteomic datasets are beginning to rival the depth and breadth of transcriptomic datasets 22 , 26 .…”

Section: Background and Summarymentioning

confidence: 99%

Global quantitative analysis of the human brain proteome and phosphoproteome in Alzheimer’s disease

et al. 2020

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Alzheimer’s disease (AD) is characterized by an early, asymptomatic phase (AsymAD) in which individuals exhibit amyloid-beta (Aβ) plaque accumulation in the absence of clinically detectable cognitive decline. Here we report an unbiased multiplex quantitative proteomic and phosphoproteomic analysis using tandem mass tag (TMT) isobaric labeling of human post-mortem cortex (n = 27) across pathology-free controls, AsymAD and symptomatic AD individuals. With off-line high-pH fractionation and liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) on an Orbitrap Lumos mass spectrometer, we identified 11,378 protein groups across three TMT 11-plex batches. Immobilized metal affinity chromatography (IMAC) was used to enrich for phosphopeptides from the same TMT-labeled cases and 51,736 phosphopeptides were identified. Of these, 48,992 were quantified by TMT reporter ions representing 33,652 unique phosphosites. Two reference standards in each TMT 11-plex were included to assess intra- and inter-batch variance at the protein and peptide level. This comprehensive human brain proteome and phosphoproteome dataset will serve as a valuable resource for the identification of biochemical, cellular and signaling pathways altered during AD progression.

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Section: Background and Summarymentioning

confidence: 99%

Global quantitative analysis of the human brain proteome and phosphoproteome in Alzheimer’s disease

et al. 2020

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“…For LC separation, ACE super C 18 was chosen for its use over a wide pH range. Both acidic and basic mobile phases were evaluated (Tan & Fanaras, ). Additionally, both methanol and acetonitrile were used as organic modifiers in the mobile phases.…”

Section: Resultsmentioning

confidence: 99%

Simultaneous quantification of candesartan and irbesartan in rabbit eye tissues by liquid chromatography–tandem mass spectrometry

Tan

Gui

Wong

et al. 2020

Biomedical Chromatography

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Diabetic retinopathy is a major cause of vision loss in adults. Novel eye-drop formulations of candesartan and irbesartan are being developed for its cure or treatment. To support a preclinical trial in rabbits, it was critical to develop and validate a new LC-MS/MS method for simultaneous quantification of candesartan and irbesartan in rabbit eye tissues (cornea, aqueous humor, vitreous body and retina/choroid). Eye tissue samples were first homogenized in H 2 O-diluted rabbit plasma. The candesartan and irbesartan in the supernatants together with their respective internal standards (candesartan-d 4 and irbesartan-d 4 ) were extracted by solid-phase extraction. The extracted samples were injected onto a C 18 column for gradient separation. The MS detection was in the positive electrospray ionization mode using the multiple reaction monitoring transitions of m/z 441 ! 263, 445 ! 267, 429 ! 207, and 433 ! 211 for candesartan, candesartan-d 4 , irbesartan and irbesartan-d 4 , respectively. For the validated concentration ranges (2-2000 and 5-5000 ng/g for candesartan and irbesartan, respectively), the within-run and between-run accuracies (% bias) were within the range of −8.0-10.0. The percentage CV ranged from 0.6 to 7.3. There was no significant matrix interference nor matrix effect from different eye tissues and different rabbits. The validated method was successfully used in the Good Laboratory Practice (GLP) study of rabbits. K E Y W O R D S candesartan, eye tissue, irbesartan, LC-MS, rabbit

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“…We found 10 mM of ammonium acetate suitable for the complete resolution of all target analytes with improved sensitivity, though concentrations ranging from 1–5 mM of ammonium acetate as mobile phase modifier are mostly reported in the literature for the chromatographic separation of PFAS [ 3 , 4 , 36 ]. The improved chromatographic peak shape, selectivity and higher signal to noise ratio obtained is attributed to the well-known advantages of high pH mobile phases in negative electrospray ionization MS [ 37 ].…”

Section: Discussionmentioning

confidence: 99%

Confirmatory Analysis of Per and Polyfluoroalkyl Substances in Milk and Infant Formula Using UHPLC–MS/MS

2021

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An ultra-high performance liquid chromatography tandem mass spectrometry method was developed and validated for the sensitive determination and unambiguous confirmation of residues of per and polyfluorinated alkyl substances (PFAS) in breastmilk, retail milk and infant formulas following two sample preparation methods. Sample pre-treatment was carried out by a simplified QuEChERS method without requiring dSPE or any further clean-up. The method was validated in accordance with the requirements of Commission Decision 657/2002/EC with slight modifications. The method displayed good linearity with R2 ranging from 0.9843–0.9998 for all target PFAS. The recovery and within-laboratory reproducibility of the method (n = 63) were in the range 60–121% and 5–28%, respectively. The decision limit, detection capability and limit of quantitation ranged from 30–60 ng kg−1 to 40–100 ng kg−1 and 5–50 ng kg−1, respectively. Acceptable matrix effect values in the range −45–29% were obtained with uncertainty of measurement lower than 25% for all target PFAS. The method displays its suitability for the sensitive and high-throughput confirmatory analysis of C4–C14 PFAS in breastmilk, dairy milk and infant formulas.

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Use of high‐pH (basic/alkaline) mobile phases for LC–MS or LC–MS/MS bioanalysis

Cited by 30 publications

References 80 publications

Global quantitative analysis of the human brain proteome and phosphoproteome in Alzheimer’s disease

Global quantitative analysis of the human brain proteome and phosphoproteome in Alzheimer’s disease

Simultaneous quantification of candesartan and irbesartan in rabbit eye tissues by liquid chromatography–tandem mass spectrometry

Confirmatory Analysis of Per and Polyfluoroalkyl Substances in Milk and Infant Formula Using UHPLC–MS/MS

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