Waters (United Kingdom)

Pyrrolizidine alkaloids (PAs) are plant toxins occurring in different foodstuffs, including teas, herbal infusions and species. Additionally, PAs may be transferred to honey and pollen when honeybees come into contact with contaminated plants. Due to their adverse effect, PAs occurrence in food must be controlled to ensure public health. Nevertheless, the presence of numeours PA epimers complicates their chromatographic separation and detection. In this regard, a method using liquid chromatography coupled with tandem mass spectrosmetry (LC-MS/MS) has been developed allowing the separation of 31 out of the 35 regulated PAs, which was sucessfully validated in different food matrices such as herbal infusions, spices and honey. Afterwards, travelling wave ion mobility spectrometry hyphenated with quadrupole time-of-flight mass spectrometry (TWIMS-QTOF) was evaluated to improve the analytical performance of PAs determination. Thus, collision cross section (CCS) values of PAs have been therefore obtained for the first time. The CCS library for PAs was also compared with predicted values by machine learning and with those meassured in real food matrices (bias <2 %). In addition, an in-house library was used in the suspect screening of PAs to complement the targeted analysis of the studied samples, all of which tested positive for several PAs.

ABSTRACT School attendance difficulties including emotionally based school avoidance (EBSA) are an ongoing concern. Over recent years, local authorities (LAs) have provided guidance for school staff and other professionals in addressing EBSA. Educational psychologists (EPs) have written or contributed significantly to guidance. In order to establish what guidance UK LAs are providing for schools and to support future refinement of EBSA guidance through a newly created evaluation tool, this current review analysed 48 UK LA EBSA guidance documents obtained between June and August 2023. Common elements were consideration of context, underlying principles, evidence base, practical support and resources. Implications for practice, limitations, and potential future research are discussed.

Kima pasir merupakan salah satu jenis kima yang masih dikonsumsi sampai saat ini oleh masyarakat pesisir di Negeri Sawai, dimakan segar maupun diolah lebih lanjut. Penelitian ini bertujuan untuk mengetahui karakteristik fisik dan komposisi kimia kima pasir segar dan olahan dari perairan Sawai Kecamatan Seram Utara, Maluku Tengah. Metode yang digunakan dalam penelitian ini adalah metode observasi terstruktur, mengamati setiap tahapan proses, mengambil sampel dan mengukur mutunya di laboratorium. Parameter fisik yang dianalisa meliputi pengukuran morfometrik. Parameter lingkungan berupa: suhu, pH dan salinitas. Komposisi kimia yang dianalisa meliputi kadar air, protein, lemak, abu karbohidrat dan susut bobot pada kima pasir segar dan kima pasir yang diolah dengan cara: kukus, goreng dan dikeringkan. Hasil penelitian menunjukkan bahwa kerang kima pasir dari perairan Sawai memiliki diameter 11- 36 cm dan berat 0,24-3,6 kg. Suhu air berkisar 29-30ºC, pH 7,5-7,8 dan salinitas 32-33 ppt. Rata-rata kadar protein, abu dan lemak daging kima pasir yang diolah dengan cara kukus, goreng, dan dikeringkan menjadi lebih tinggi dari daging kima segar sedangkan kadar air daging kima setelah kukus, goreng dan dikeringkan menjadi lebih rendah. Daging kima yang telah diolah juga mengalami penyusutan bobot dari bahan segarnya. Kadar protein dan abu tertinggi terdapat pada kima pasir yang dikeringkan sebesar 44,8% dan 4,83%, kadar lemak tertinggi pada kima pasir goreng sebesar 13,67%, dan kadar air terendah terendah pada kima pasir yang dikeringkan sebesar 45,02%, sedangkan susut bobot tertinggi terdapat pada kima yang dikeringkan dengan penyusutan sebesar 71,79% dan terendah pada kima goreng sebesar 46,21%.

Abstract Background Primary aldosteronism (PA) is a common cause of hypertension, whereby uncontrollable amounts of aldosterone are produced by a benign tumour or hyperplasia of the adrenal glands. Excess aldosterone results in significant sodium reabsorption in the kidneys, increasing water retention and blood volume, thereby causing hypertension. The renin-angiotensin-aldosterone system (RAAS) regulates the production of aldosterone and in this system, renin and aldosterone should move in synchronicity with each other throughout the day. Therefore, these two components are used to assess the status of the RAAS, particularly in the evaluation of new therapies in clinical research studies. Historically, the assessments of aldosterone and plasma renin activity (PRA) have been performed using separate methods using immunoassay or more recently liquid chromatography - tandem mass spectrometry (LC-MS/MS) platforms. One of the benefits of using LC-MS/MS for clinical research is the ability to measure multiple analytes across the proteome and metabolome using the same system and even in the same analysis to provide more information in less time and save costs. Here we evaluate a single LC-MS/MS method for the combined measurement of plasma aldosterone and renin activity for clinical research purposes. Methods Aldosterone certified reference material (Merck, UK) and Angiotensin I (Cambridge BioScience, UK) were used to create calibrators in 2% Bovine Serum Albumin (BSA) in Phosphate Buffered Saline (PBS). In-house QC material prepared in both 2% BSA in PBS and K2EDTA plasma (BioIVT, UK), were used to evaluate method precision. Plasma samples were analyzed using the newly developed method and the quantified results were compared to separate independent LC-MS/MS methods for aldosterone and plasma renin activity. Plasma samples were treated with generation buffer (Sodium acetate, EDTA, acetic acid, SBTI and PMSF) and mixed for three hours at 37 °C. Samples were precipitated, diluted and centrifuged prior to SPE. Sample supernatant was transferred to a Waters Oasis™ µElution 96 Well Plate, followed by a wash and elution. Using an ACQUITY™ UPLC™ I-Class System, samples were injected onto a Waters XBridge™ C8, 2.5 µm, 2.1 × 50 mm Column using a water/methanol/ammonium fluoride gradient elution profile and quantified with a Waters Xevo™ TQ Absolute Mass Spectrometer. Results The method demonstrated no significant carryover or matrix effects and was shown to be linear from 10 - 2500 pg/mL for aldosterone and 0.1–25 ng/mL/h for PRA. Analytical sensitivity investigations indicate the analytical sensitivity of this method would allow precise quantification (&amp;lt;20%) at 10 pg/mL and 0.1 ng/mL/h, for aldosterone and PRA, respectively. Coefficients of variation (CV) for total precision and repeatability on 5 analytical runs for low, mid and high QCs were all &amp;lt;10% (n = 25) for aldosterone and PRA. Comparison with samples previously analyzed by an independent LC-MS/MS method demonstrated good agreement for aldosterone and PRA. Conclusions We have successfully quantified aldosterone and renin activity in plasma in a single method using an SPE protocol with LC-MS/MS analysis, for clinical research purposes. The method demonstrates excellent linearity and precision, with minimal matrix effects. For Research Use Only. Not for Use in Diagnostic Procedures.

Abstract Evaluating management strategies for fish catch development requires knowledge of movement patterns and their spatial distribution. The Caspian kutum (Rutilus kutum, Kamenskii, 1901) is an important commercial species throughout the southern coasts of the Caspian Sea. Stable isotope ratios are powerful indexes that simplify the understanding of the migration of aquatic animals. This research determined the stable isotope ratio of carbon (δ13C) and nitrogen (δ15N) for Rutilus kutum movement at 10 sites along the southern coastline of the Caspian Sea from January to December 2017. Spatial and temporal variations in stable isotope values of the coastal communities in the Caspian Sea remain poorly understood. These findings suggest that individual variation, but with a strong overall decline in δ13C and increasing in δ15N and δ13C/δ15N ratio with age, too. These isoscpes showed that the δ15N ratio increased and δ13C decreased from the east (Gomishan) to the west (Astara).

Unambiguous identification of distinct proteoforms and their biological functions is a significant analytical challenge due to the many combinations of post-translational modifications (PTM) that generate isomeric proteoforms. Resulting chimeric tandem mass spectra hinder detailed structural characterization of individual proteoforms for mixtures with more than two isomers. Large isomeric peptides and intact isomeric proteins are extremely difficult to distinguish with traditional chromatographic separation methods. Gas-phase ion separation techniques such as ion mobility spectrometry (IMS) methods now offer high resolving power that may enable separation of isomeric biomolecules, such as peptides and proteins. We explored novel high-resolution cyclic ion mobility spectrometry (cIM) combined with an electro-magnetostatic cell for "on-the-fly" electron capture dissociation (ECD) for separation and sequencing of large isomeric peptides. We demonstrate the effectiveness of this approach on ternary mixtures of mono- and trimethylated isomers of histone H3 N-tails (∼5.4 kDa), achieving a complete separation of these isomers with an average resolving power of ∼400 and a resolution of 1.5 and with nearly 100% amino acid sequence coverage. Our results demonstrate the potential of the cIM-MS/MS(ECD) technology to enhance middle-down and top-down proteomics workflows, thereby facilitating the identification of near-identical proteoforms with essential biological functions in complex mixtures.

Background & AimsLipid metabolism plays an important role in liver pathophysiology. The liver lobule asymmetrically distributes oxygen and nutrition, resulting in heterogeneous metabolic functions. Periportal and pericentral hepatocytes have different metabolic functions, which lead to generating liver zonation. We developed spatial metabolic imaging using desorption electrospray ionisation mass spectrometry to investigate lipid distribution across liver zonation with high reproducibility and accuracy. MethodsFresh frozen livers from healthy mice with control diet were analysed using desorption electrospray ionisation mass spectrometry imaging. Imaging was performed at 50 μm × 50 μm pixel size. Regions of interest (ROIs) were manually created by co-registering with histological data to determine the spatial hepatic lipids across liver zonation. The ROIs were confirmed by double immunofluorescence. The mass list of specific ROIs was automatically created, and univariate and multivariate statistical analysis were performed to identify statistically significant lipids across liver zonation. ResultsA wide range of lipid species was identified, including fatty acids, phospholipids, triacylglycerols, diacylglycerols, ceramides, and sphingolipids. We characterised hepatic lipid signatures in three different liver zones (periportal zone, midzone, and pericentral zone) and validated the reproducibility of our method for measuring a wide range of lipids. Fatty acids were predominantly detected in the periportal region, whereas phospholipids were distributed in both the periportal and pericentral zones. Interestingly, phosphatidylinositols, PI(36:2), PI(36:3), PI(36:4), PI(38:5), and PI(40:6) were located predominantly in the midzone (zone 2). Triacylglycerols and diacylglycerols were detected mainly in the pericentral region. De novo triacylglycerol biosynthesis appeared to be the most influenced pathway across the three zones. ConclusionsThe ability to accurately assess zone-specific hepatic lipid distribution in the liver could lead to a better understanding of lipid metabolism during the progression of liver disease. Impact and ImplicationsZone-specific hepatic lipid metabolism could play an important role in lipid homoeostasis during disease progression. Herein, we defined the zone-specific references of hepatic lipid species in the three liver zones using molecular imaging. The de novo triacylglycerol biosynthesis was highlighted as the most influenced pathway across the three zones.

Properly implemented, metabolic and lipidomic profiling can provide a deeper understanding of mammalian, plant and bacterial biology. These omics-tools have developed and matured over the last 40-years and are now being deployed to provide valuable information in epidemiological studies, drug toxicology and pharmacology, disease biology and progression and patient stratification. LC/MS has become the technology of choice for both metabolic and lipid profiling, due to its speed, sensitivity and structural elucidation capabilities. In the preceding two decades there have been many technological and methodological advances in LC/MS that have facilitated the evolution of the technology into a rugged, reliable, and easily deployed tool. These advances include, but are not limited to, improvements in chromatography (phases, columns, and delivery system), instruments for mass spectrometry, optimization of sample preparation, the introduction of ion mobility, data analysis tools, metabolite databases, harmonized protocols, and the more widespread use of quality control methods and reference standards/matrices. Here, recent developments and advances in high throughput liquid chromatography/high resolution mass spectrometry for metabolic phenotyping are described. These advances which may provide improved feature detection, increased laboratory efficiency and data quality, as well as “biomarker” identification, are discussed in relation to their potential application to the analysis of large clinical studies, or biobank collections.