Ion Mode Research Articles

UHPLC-QTOFMS Urine Drug Screening With Dilute-and-Shoot Sample Preparation and Vacuum-Insulated Probe-Heated Electrospray Ionization.

We developed a method for comprehensive urine drug screening by applying dilute-and-shoot extraction and vacuum-insulated probe-heated electrospray ionization with ultra-high performance liquid chromatography high-resolution quadrupole time-of-flight mass spectrometry (DS-UHPLC-VIP-HESI-QTOFMS). The method involved five-fold post-hydrolysis dilution of urine samples and chromatography on a C18 UHPLC column prior to QTOFMS analysis. The recently introduced VIP-HESI ion source was chosen due to its enhanced ionization efficiency and compatibility with UHPLC-QTOFMS. Extensive data was acquired in positive ion mode with a low collision energy (7 eV) and an elevated collision energy (30 eV), using the broadband collision-induced dissociation data acquisition scan mode that continuously generated high-resolution and accurate mass for parent and fragment qualifier ions, and parent ion isotopic patterns. Compound identification was performed against an in-house database with 1263 compound entries, using an automated post-run reverse target database search with preset identification criteria. Method validation with 56 different drugs showed acceptable results for the limit of identification (median 5 ng/mL), matrix effects (70-130%), repeatability of retention times (< 1%), mass accuracy (< 1 mDa), as well as for specificity and stability. As compared with an established UHPLC-QTOFMS method relying on solid-phase extraction and conventional electrospray ionization, DS-UHPLC-VIP-HESI-QTOFMS produced comparable results from authentic clinical urine samples for most drugs, but showed clearly improved detectability for pregabalin, gabapentin, and ritalinic acid. We anticipate that the new method will be a step forward for laboratories performing routine urine drug screening due to its fast turnaround time, reduced manual workload, cost efficiency, and broad substance coverage.

Insights into the Chemical Exposome during Pregnancy: A Non-Targeted Analysis of Preterm and Term Births.

Human-made chemicals are ubiquitous, leading to chronic exposure to complex mixtures of potentially harmful substances. We investigated chemical exposures in pregnant women in New York City by applying a non-targeted analysis (NTA) workflow to 95 paired prenatal urine and serum samples (35 pairs of preterm birth) collected as part of the New York University Children's Health and Environment Study. We analyzed all samples using liquid chromatography coupled with Orbitrap high-resolution mass spectrometry in both positive and negative electrospray ionization modes, employing full scan and data-dependent MS/MS fragmentation scans. We detected a total of 1524 chemical features for annotation, with 12 chemicals confirmed by authentic standards. Two confirmed chemicals dodecyltrimethylammonium and N,N-dimethyldecylamine N-oxide appear to not have been previously reported in human blood samples. We observed a statistically significant differential enrichment between urine and serum samples, as well as between preterm and term birth (p < 0.0001) in serum samples. When comparing between preterm and term births, an exogenous contaminant, 1,4-cyclohexanedicarboxylic acid (tentative), showed a statistical significance difference (p = 0.003) with more abundance in preterm birth in serum. An example of chemical associations (12 associations in total) observed was between surfactants (tertiary amines) and endogenous metabolites (fatty acid amides).

Medium-chain fatty acid triglycerides improve feed intake and oxidative stress of finishing bulls by regulating ghrelin concentration and gastrointestinal tract microorganisms and rumen metabolites

BackgroundAs a feed additive, medium-chain fatty acids (MCFAs)/medium-chain fatty acid triglycerides (MCTs) have been used in ruminant production, but mostly added in the form of mixed esters. Studies have shown that MCTs may have a positive effect on feed intake or oxidative stress in animals, but it is unclear which MCT could play a role, and the mechanism has not been elucidated. In this study, the effects of individual MCT on growth performance, serum intake-related hormones, and oxidative stress indices in finishing bulls were investigated and further studied the effects of MCT supplementation on gastrointestinal tract bacteria and rumen fluid metabolomics.ResultsFour ruminally fistulated Yanbian cattle (bulls) were selected in 4 × 4 Latin square designs and allocated to four treatment groups: a control group (CON) fed a basal diet (total mixed ration, TMR), three groups fed a basal diet supplemented with 60 g/bull/day glycerol monocaprylin (GMC, C8), glycerol monodecanoate (GMD, C10), and glycerol monolaurate (GML, C12), respectively. Compared with the CON group, GMD tended to increase the dry matter intake (DMI) of finishing bulls (P = 0.069). Compared with the CON group, GMD significantly increased the concentration of ghrelin O-acyl transferase (GOAT), total ghrelin (TG), acylated ghrelin (AG), and orexins (P < 0.05) and significantly decreased the concentrations of hydrogen peroxide (H2O2), malondialdehyde, reactive oxygen species (ROS), and lipopolysaccharides (LPS) in the serum of finishing bulls (P < 0.05). Compared with the CON group, GMD and GML significantly increased the concentrations of total antioxidant capacity (T-AOC), catalase, glutathione peroxidase (GSH-PX), glutathione reductase (GR), and nitric oxide (NO) in the serum of finishing bulls (P < 0.05). Compared with the CON group, there were 5, 14, and 6 significantly different bacteria in the rumen digesta in the C8, C10, and C12 groups, respectively; there were 3, 10, and 5 significantly different bacteria in the rumen fluid in the C8, C10, and C12 groups, respectively; and only one differential bacteria (genus level) in the feces among the four treatment groups. Compared with the CON group, there were 3, 14, and 15 significantly differential metabolites identified under positive ionization mode in the C8, C10, and C12 groups, respectively, while under negative ionization mode were 3, 11 and 14, respectively. Correlation analysis showed that there was a significant correlation between DMI, GOAT, AG, GSH-PX, LPS, gastrointestinal tract bacteria, and rumen fluid metabolites.ConclusionsOur findings revealed that different types of MCTs have different application effects in ruminants. Among them, GMD may improve the feed intake of finishing bulls by stimulating the secretion of AG. GMD and GML may change gastrointestinal tract microorganisms and produce specific rumen metabolites to improve the oxidative stress of finishing bulls, and ghrelin may also be involved. This study enlightens the potential mechanisms by which MCT improves feed intake and oxidative stress in finishing bulls.5d9kULzJFQsQ3ajLfa--XDVideo

Development and validation of HPLC-UV and LC-MS/MS methods for the quantitative determination of a novel aminothiazole in preclinical samples

Aminothiazoles are the important class of chemical groups which have proven their broad range of biological activities. A novel aminothiazole (21MAT) was quantified in analytical solutions using a high-performance liquid chromatography (HPLC) approach that was developed and partially validated for the analysis of in vitro experimental samples. An isocratic elution on reverse phase Phenomenex® Luna C18 (50 mm × 4.6 mm, 5 μm) column with 55% 0.1% v/v orthophosphoric acid in water and 45% of orthophosphoric acid in acetonitrile at a flow rate of 1 mL/min was used. The analyte was detected at 272 nm. Similar to this, a robust bioanalytical technique, LC-mass spectrometry (LC-MS/MS) was created and verified to measure 21MAT in rat plasma for use in in vitro screening study samples and early-stage pharmacokinetic research. The protein precipitation method was used to extract 21MAT from plasma. The mixture of 95: 5% v/v methanol: acetonitrile and 0.1% v/v formic acid, along with 15% of 5 mM ammonium formate solution, was used to separate the mixture on a reverse phase Waters Xterra RP® C18 (150 mm × 4.6 mm, 5 μm) column at a flow rate of 1 mL/min. Using electro spray ionisation mode in multiple reaction monitoring mode, the analyte and internal standard (a structural analogue) were both identified. According to current criteria, all validation parameters (specificity, selectivity, accuracy, precision, recovery, matrix factor, hemolysis effect, and stability) were evaluated in rat plasma. The area response of 21MAT was found to be linear over the concentration range of 1.25–1250 ng/mL in rat plasma. Both techniques are suitable for use in any format of preclinical research and were sufficiently reliable to measure 21MAT precisely in various matrices. In silico prediction helped in understanding absorption, distribution, metabolism, excretion, and toxicity (ADMET) behaviour of the molecule. Both developed LC-MS/MS and HPLC-UV methods were successfully used to quantify the analyte in in vitro screening study samples.

Systematic Characterisation of the Fragmentation of Flavonoids Using High-Resolution Accurate Mass Electrospray Tandem Mass Spectrometry

Flavonoids are a class of polyphenolic secondary metabolites found in plants. Due to their ubiquity in our daily dietary intake and their major anti-oxidative, anti-inflammatory and anti-mutagenic activities, they have been a major focus of wide-ranging research for the past two decades. Mass spectrometry combined with liquid chromatography is one of the most popular techniques for the analysis of flavonoids. In this study, high-resolution accurate mass electrospray tandem mass spectrometry was used to study 30 flavonoids in both positive and negative ionisation modes. From the data obtained, common losses were summarised and compiled. Dominating neutral losses were tabulated. The radical loss of CH3· was observed in flavonoids containing methoxy groups and three key diagnostic product ions were identified. These were m/z 153 (indicative of two OH groups on ring A) m/z 167 (indicative of one OH and one methoxy group on ring A) and m/z 151 (a flavanol, with no ketone oxygen but two OH groups on ring A). These will be useful in structural elucidation of unknown flavonoids and flavonoid metabolites. Energy breakdown graphs were utilised to distinguish between three pairs of structural isomers, and to help rationalise proposed fragmentation pathways. Lastly, a competition of loss of CH3· and methane was reported for rhamnetin and isorhamnetin in the negative ion mode for the first time. Proposed fragmentation pathways were given to rationalise the differences in peak intensities for this competitive process.

Peroxydisulfate Activation by Biochar from Banana Peel Promoted with Copper Phosphide for Bisphenol S Degradation in Aqueous Media

In this work, the decomposition of bisphenol S (BPS) by biochar derived from banana peel (BPB) promoted by copper phosphide (Cu3P) was examined. Different materials with Cu3P loadings from 0.25 to 4.00 wt.% on biochar were synthesized, characterized using the Brunauer–Emmett–Teller (BET) method, X-ray diffraction (XRD) and a scanning electron microscope (SEM) equipped with an energy dispersive spectrometer (EDS), and evaluated. Nearly all of the synthesized materials exhibited low to moderate adsorption capacity, attributable to their limited surface area (&lt;3.1 m2/g). However, in the presence of sodium persulfate (SPS), the 2%Cu3P/ΒPB/SPS system was capable of removing 90% of 500 μg/L BPS in less than 10 min. The system’s performance was enhanced under inherent pH, and the reaction rate followed pseudo-first-order kinetics with respect to BPS and persulfate concentrations. Interestingly, the presence of 250 mg/L of sodium chloride had a negligible effect, while low to moderate inhibition was observed in the presence of bicarbonates and humic acid. In contrast, significant retardation was observed in experiments performed in real matrices, such as secondary effluent (WW) and bottled water (BW). According to scavenging experiments, both radical and non-radical mechanisms participated in the BPS degradation. Four transformation products were identified using the UHPLC/TOF-MS system in negative ionization mode, with two of them having higher molecular weights than BPS, while the other two TBPs involved the ring-opening reaction, and a BPS decomposition pathway was proposed.

A public grid of radiative transfer simulations for Lyα and metal lines in idealised galactic outflows

The vast majority of star-forming galaxies are surrounded by large reservoirs of gas ejected from the interstellar medium. Ultraviolet absorption and emission lines represent powerful diagnostics to constrain the cool phase of these outflows, through resonant transitions of hydrogen and metal ions. The interpretation of these observations is often remarkably difficult as it requires detailed modelling of the propagation of the continuum and emission lines in the gas. To this aim, we present a large public grid of ≈20 000 simulated spectra that includes H I Lyα and five metal transitions associated with Mg II, C II, Si II, and Fe II which is accessible online. The spectra have been computed with the RASCAS Monte Carlo radiative transfer code for 5760 idealised spherically symmetric configurations surrounding a central point source emission, and characterised by their column density, Doppler parameter, dust opacity, wind velocity, as well as various density and velocity gradients. Designed to predict and interpret Lyα and metal line profiles, our grid exhibits a wide diversity of resonant absorption and emission features, as well as fluorescent lines. We illustrate how it can help better constrain the wind properties by performing a joint modelling of observed Lyα, C II, and Si II spectra. Using CLOUDY simulations and virial scaling relations, we also show that Lyα is expected to be a faithful tracer of the gas at T ≈ 104 − 105 K, even if the medium is highly ionised. While C II is found to probe the same range of temperatures as Lyα, other metal lines merely trace cooler phases (T ≈ 104 K). As their gas opacity strongly depends on gas temperature, incident radiation field, metallicity and dust depletion, we caution that optically thin metal lines do not necessarily originate from low H I column densities and may not accurately probe Lyman continuum leakage.

Rapid and Effective Determination of Ethyl Glucuronide in Hair by Micro Extraction by Packed Sorbent (MEPS) and LC-MS/MS.

Ethyl glucuronide (EtG) in hair is a reliable biomarker of alcohol consumption habits. Due to its small concentration incorporated into hair, analytical methods sensitive enough to reliably quantify EtG in this matrix are required. Sample preparation is critical in hair analysis, especially for EtG, for which extraction efficiency and matrix effect can strongly influence the results; furthermore, miniaturized methods are sought, to reduce solvent use and times of sample preparation. A micro extraction by packed sorbent (MEPS) procedure coupled to a high-performance liquid chromatography-tandem mass spectrometry method was developed and validated for quantitation of EtG in human hair samples. Fifty milligrams of hair samples were cut into snippets and extracted in water. The cleanup of the extract was carried out by using a MEPS syringe packed with anion exchange sorbent (SAX); all parameters for conditioning, washing, loading and eluting steps were optimized and the eluted aqueous volume was directly injected in the LC-MS/MS system operating in the negative ionization mode. The method was fully validated assessing LOD, LOQ, calibration curve, repeatability, accuracy, matrix effect and carryover. The method was subsequently applied to QCs and authentic hair samples. The developed MEPS method is quick and effective, with low solvent purchase and discard costs, allowing the differentiation between social drinkers and chronic excessive alcohol consumers, according to the cut-offs established by the Society of Hair Testing (SoHT).

UPLC/HR-ESI-MS/MS and GC/MS profiling of Eriobotrya japonica L. fruit in correlation to its antioxidant, anti-inflammatory, and anti-arthritic effects.

Eriobotrya japonica Lindl. (Loquat) fruit is a subtropical edible fruit originally from China. It grows well in Egypt, but it is not widely known. In the current study, the fruit was extracted with 80% ethanol to get the total ethanol extract (TEE). A part of which was fractionated by dichloromethane to yield polar and nonpolar fractions (PF and NPF). The antioxidant and anti-inflammatory activities of the TEE were in vitro evaluated. The complete Freund's adjuvant (CFA) arthritis model was used to explore the in vivo biological assessment of the anti-arthritic properties in vivo of the TEE, PF, and NPF of the fruit. Additionally, the inspected limbs detached from all animals were subjected to histological inspection. Moreover, GC/MS analysis of the unsaponifiable (USF) and saponifiable (SF) fractions of the NPF was performed. Furthermore, 64 metabolites from various chemical classes were identified using UHPLC/HR-MS/MS analysis of the TEE of the fruit in both positive and negative ionization modes. The positive ionization mode of loquat fruit allowed for the first time the detection of two kinds of lyso-glycerophospholipids (Lyso-GPLs): lyso-glycerophosphoethanolamines (Lyso-PtdEtn) and lyso-glycerophosphocholines (Lyso-PtdCho). The fruit extracts exhibited a notable in vivo anti-arthritic activity by decreasing paw thickness in the treated rats and adjusting the inflammatory mediators. The TEE showed the highest anti-arthritic activity, followed by the PF that showed an observed activity, while the NPF exhibited the lowest activity. Histopathological findings showed a marked improvement in the arthritic condition of the excised limbs. Thus, E. japonica fruit may be considered as a promising natural antioxidant and anti-arthritic agent.

Measurement Uncertainty and Validation for Quantification of Marijuana Metabolite: (−)-11-nor-9-Carboxy-Δ9-THC in Human Urine by GC-MS/MS

Background: Since the International Olympic Committee (IOC) was established, sports doping control analyses have revealed a high rate of positive cases for cannabinoids. Cannabinoids were banned in all sports where they were used in competition as per the Prohibited List published annually. Further, it was also included in the threshold drug category. Consequently, developing a reliable method for urine Cannabinoids metabolite quantification plays a pivotal role in sports dope testing. Objective: This work aimed to develop and validate a reliable, cost-effective, robust gas chromatography-tandem mass spectrometry method for detecting (−)-11-nor-9-Carboxy-Δ9- THC component in human urine samples, in compliance with ICH and WADA guidelines. Method: The sample preparation was done by enzymatic hydrolysis for deconjugation, further proceeded with solid phase extraction (SPE), liquid-liquid extraction (LLE), and using an XAD2 column, and N-methyl trimethylsilyl trifluoroacetamide (MSTFA) for derivatization. Results: The linearity was obtained in a range of 50–300 ng/mL, and the correlation coefficient was found to be higher than 0.99. Throughout the entire validation study, the difference in Retention Time (RT) for the analyte, including the Internal Standard (IS), was shown to be less than 1.0%. The quantification limit (LOQ) was calculated at a level of 50 ng/mL in human urine samples for the 3 most abundant ion transitions. The detection limit (LOD) was established at 4 ng/mL. Conclusion: The accuracy, precision, linearity, recovery, quantification limit, and selectivity by GC-MS/MS technique were found acceptable and well satisfactory while following the ICH guidelines. The developed method has been proven to be fit for purpose in accordance with the enforced Guidelines of WADA.

Hanle Effect for Lifetime Determinations in the Soft X-Ray Regime.

By exciting a series of 1s^{2} ^{1}S_{0}→1snp^{1}P_{1} transitions in heliumlike nitrogen ions with linearly polarized monochromatic soft x rays at the Elettra facility, we found a change in the angular distribution of the fluorescence sensitive to the principal quantum number n. In particular it is observed that the ratio of emission in directions parallel and perpendicular to the polarization of incident radiation increases with higher n. We find this n dependence to be a manifestation of the Hanle effect, which served as a practical tool for lifetime determinations of optical transitions since its discovery in 1924. In contrast to traditional Hanle effect experiments, in which one varies the magnetic field and considers a particular excited state, we demonstrate a "soft x-ray Hanle effect" which arises in a static magnetic field but for a series of excited states. By comparing experimental data with theoretical predictions, we were able to determine lifetimes ranging from hundreds of femtoseconds to tens of picoseconds of the 1snp^{1}P_{1} levels, which find excellent agreement with atomic-structure calculations. We argue that dedicated soft x-ray measurements could yield lifetime data that are beyond current experimental reach and cannot yet be predicted with sufficient accuracy.

A Liquid Chromatography‐Tandem Mass Spectrometry Bioanalytical Method Development and Validation for the Determination of Pacritinib in Plasma

ABSTRACTThe primary objective of the current work is to establish and verify an accurate and linear liquid chromatography‐electrospray ionization‐tandem mass spectrometry procedure for quantifying Pacritinib. An effective chromatographic resolution was obtained using the Hypersil Gold (50 × 4.6 mm, 2.1 µm) C18 column. The mobile phase is a mixture of methanol, 0.1% formic acid, and acetonitrile in the proportion of 20:15:65 (%v/v/v). The procedure involved closely monitoring executed ionic transitions of m/z 473.1/376.2 for Pacritinib and 584.26/101.1 for Brigatinib internal standard in multiple reaction monitoring mode. A strong correlation value (r2) of 0.9997 is associated with the linear plot regression line, which can be represented as y = 0.0001x − 0.0008. The relative standard deviation (RSD) results for the matrix effect were 3.63% and 3.57%, respectively, when the quality control (QC) level was low and high, respectively. Over the course of the study, the percentage average recoveries for Pacritinib were found to be 103.27% in high QC, 97.59% in medium QC, and 94.28% in low QC, respectively. The values that were obtained for the QC samples (0.378, 1.058, 7.56, and 11.34 µg/mL) varied from 2.00% to 4.03%. The developed method was useful for evaluating Pacritinib in biological samples for the purposes of QC, forensics, and bioavailability investigations for individuals.

Empirical Approach to Quantifying Sensitivity in Different Chemical Ionization Techniques for Organonitrates and Nitroaromatics Constrained by Ion-Molecule Reaction and Transmission Efficiency.

Accurate identification and quantification of nitro-containing species are of great significance to understanding their chemical behaviors in the atmosphere. By optimizing the operational conditions of the H3O+ and NO+ ionization modes in a proton-transfer-reaction time-of-flight mass spectrometer (PTR-TOF-MS) and evaluating the performance of an iodide chemical ionization mass spectrometer (I- CIMS), this study leveraged the individual advantages of each ionization mode to effectively detect a diverse array of nitroaromatics and organonitrates (ONs). The H3O+ ionization mode largely fulfilled the criteria for real-time monitoring of gas-phase alkyl-, aryl-, and hydroxy-nitrates, and nitrophenols, albeit its reduced sensitivity toward ONs due to extensive fragmentation. In contrast, the NO+ mode demonstrated enhanced sensitivity for ONs with less fragmentation than the H3O+ mode. The I- CIMS featured distinguished sensitivity toward oxidized compounds containing polar functional groups, particularly increasing with the incorporation of hydroxyl, carboxyl, or nitrate groups. Further, we developed a calibration-based semiquantitative framework to enhance the accuracy of sensitivity estimation, constrained by ion-molecule reaction, transmission efficiency, along with possible decomposition of ion-clusters, with uncertainties ranging from 21% to 41% for H3O+ and 21-43% for NO+. Given considerable discrepancies (up to 1 order of magnitude) between measured and predicted sensitivity in I- CIMS using previously reported log-linear fitting, a declustering voltage (dV50)-based categorization approach was introduced, leading to a 5-fold improvement in measurement accuracy and an overall uncertainty of I- CIMS in quantifying nitro-containing species varying from 27% to 60%.

An Ultra-Fast Green UHPLC-MS/MS Method for Assessing the In Vitro Metabolic Stability of Dovitinib: In Silico Study for Absorption, Distribution, Metabolism, Excretion, Metabolic Lability, and DEREK Alerts.

Background and Objectives: Dovitinib (DVB) is a pan-tyrosine kinase inhibitor (TKI) that can be administered orally. In September 2023, the FDA granted Oncoheroes approval to proceed with an Investigational New Drug (IND) application for dovitinib. This application is intended for the treatment of relapsed or advanced juvenile solid tumors, namely, osteosarcoma. Materials and Methods: The target of the present study was to develop a rapid, green, accurate, and sensitive UHPLC-MS/MS method for measuring DVB levels in human liver microsomes (HLMs). The validations of the HLMs were performed via the established UHPLC-MS/MS approach, as stated in the US FDA reported guidelines for the standards of bioanalytical method validation protocol. The StarDrop in silico software package (version 6.6), which involves the DEREK and WhichP450 in silico modules, was used to check the DVB structure for hazardous alerts and metabolic instability. The DVB and encorafenib (EFB), internal standard, and chromatographic peaks were successfully separated using a reversed phase column (an Eclipse Plus Agilent C8 column) and an isocratic mobile phase. The production of DVB parent ions was accomplished by utilizing the positive ionization mode of an ESI source. The identification and measurement of DVB daughter ions were conducted using the MRM mode. Results: The inter-day accuracy and precision exhibited a spectrum of values in the range of -0.56% to 9.33%, while the intra-day accuracy and precision showcased a range of scores between 0.28% and 7.28%. The DVB calibration curve showed a linear relationship that ranged from 1 to 3000 ng/mL. The usefulness of the currently validated UHPLC-MS/MS method was approved by the lower limit of quantification (LLOQ) of 1 ng/mL. The AGREE findings demonstrate that the UHPLC-MS/MS method had a noteworthy degree of ecological greenness. The in vitro half-life (t1/2) and intrinsic clearance (Clint) of DVB were calculated to be 15.48 min and 52.39 mL/min/kg, respectively, which aligned with the findings from the WhichP450 software (version 6.6). Conclusions: Via the usage of in silico software, it has been observed that making small changes to the structure of the aryl piperazine ring and quinolinone moieties, or replacing these groups in the drug design process, shows potential for enhancing the metabolic safety and stability of newly developed derivatives compared to DVB.

Polychlorinated Biphenyl Levels and Associated Health Risks in Indoor Atmosphere of Beauty Salons

Exposure to high concentrations of Polychlorinated Biphenyl (PCBs) has negative impacts on human wellbeing and the climate. This study determined the concentration, sources and health risks of PCBs in selected beauty shops in Ilorin, Kwara state. Air samples from fourteen beauty salons were taken using Solvent-Impregnated Polyurethane Foam (SIP-PUF) passive samplers for 30 days. The concentration of PCBs was determined with Gas Chromatography-Mass Spectrometry (GC–MS) operated in a Selected Ionization Mode (SIM). The health risk assessment of the PCBs was estimated using the Toxicity Equivalence Quotient (TEQ), Incremental Life Cancer Risk (ILCR), and Hazard Quotient (HQ) prescribed by United State Environmental Protection Agency (USEPA). The Positive Matrix Factorization (PMF) method was used in the source apportionment study. The average concentration of the PCBs ranged from 0.11–3.32 µg/m3 . The average TEQs for the PCBs in the beauty salon ambient air ranged between 2.96 × 10−1 - 9.30 × 10−1 ng WHO-TEQ/m3 . ILCRs and HQs estimated for the beauty shops considered were lower than 10-6 and 1 (USEPA set limit) for both adults and children. Eight factors were identified to be associated with the PCB sources; the most predominant sources are combined paint and pigment and mixed sources, which accounted for 20.08 and 28.91% of the total PCBs, respectively.

A-316 A quantitative gas chromatography tandem mass spectrometry method for metabolic profiling of urine organic acids and acylglycines

Abstract Background The analysis of urine organic acids (UOA) and acylglycines (UAG) are an essential investigation for the diagnosis inborn errors of metabolism (IEMs). The vast majority of methods for these analytes use gas chromatography mass spectrometry (GC-MS) and are only qualitative. Gas chromatography tandem mass spectrometry (GC-MS/MS) offers greater sensitivity and selectivity and enables the combination of qualitative screening with quantitative analysis. We describe the development and validation results of a quantitative GC-MS/MS method. Methods Urine creatinine concentrations were measured (CobasPro, Roche Diagnostics) and normalized to 1.25 mmol/L. After internal standard addition, each urine specimen, calibration standard and QC were incubated with a hydroxylamine solution followed by a liquid-liquid extraction. Further sample concentration permitted the isolated UOA and UAG to be derivatized using N,O-bis(trimethylsilyl)trifluoroacetamine (BSTFA) with 1% chlorotrimethylsilane (TMCS) prior to injection. GC-MS/MS analysis was performed using a GC-MS-TQ8050 triple quadrupole system (Shimadzu) with a 30 m DB-5MS (Agilent J&amp;W) capillary column (0.25 mm, ID of 0.25 µm). Split injection mode was deployed with an initial column temperature of 70°C. The mass spectrometer was operated in electron ionization (EI) and multiple reaction monitoring (MRM) modes. Results The optimal temperature gradient for high-resolution UOA and UAG separations was derived and their respective retention times determined. MS/MS detection parameters were optimized to permit the identification of precursor and production ions for all (N=36) derivatized analytes. Total analysis time was 33.8 min per injection. This method permits the measurement of 11 samples in one batch and is highly linear for all analytes (R^2 &amp;gt;0.99 and average slope 1.04). The limit of quantification (LOQ) was established and ranged from &amp;lt;0.05 to 2.1 µmol/mmol creatinine. Intra- and inter-day imprecision (CV%) was determined using matrix-matched abnormal and normal QC. Intra-day imprecision (N=10) ranged from 1.3% (2-ketoglutaric acid) to 9.7% (3-hydroxybutyric acid). Inter-day imprecision (N=30 over 15 days) ranged from 2.2% (ethylmalonic acid and methylmalonic acid) to 20.5% (3-hydroxy-3-methylglutaric acid). The method had an average accuracy of 113±14% for analytes included in the ERNDiM quantitative organic acids (urine) external quality assurance program. For analytes not included in this proficiency testing, the method showed good agreement when compared to a national reference laboratory, with average Deming correlation coefficients and regression slopes being 0.9944 and 1.1, respectively. No interferences were detected when monitoring the analyte quantifier and qualifier ion ratios in patient urine. Conclusions The devised GC-MS/MS protocol permits the unbiased identification and quantification of UOA and UAG used to investigate IEMs. The method has acceptable sensitivity, specificity, precision and accuracy for clinical routine clinical testing.

B-168 Development and Validation of a Quantitative Ultra-Performance Liquid Chromatography Quadrupole Time-of-Flight (UPLC-QToF) Method for Urine Organic Acid Analysis

Abstract Background Urine organic acid (UOA) analysis is essential for the diagnosis of inborn errors of metabolism (IEMs). Traditionally, UOA analysis is performed with gas chromatography-mass spectrometry (GC-MS) and requires time-consuming sample preparation steps including liquid-liquid extraction and derivatization. The rapid development of Ultra-Performance Liquid Chromatography Tandem Mass Spectrometry (UPLC-MS/MS) in the past few years provides the opportunity to perform UOA analysis with a dilute-and-shoot methodology. We describe the development and validation of a quantitative Ultra-Performance Liquid Chromatography Quadrupole Time-of-Flight (UPLC-QToF) method for UOA analysis. Methods Urine specimens were diluted to normalize creatinine concentrations to 1 mmol/L. 20 µL of urine specimen (diluted), calibrator, or quality control (QC) material was mixed with 400 µL of mobile phase A (0.05% formic acid in water) and a mixture of isotope-labeled internal standards. After centrifugation, 10 µL of the supernatant was analyzed using a Xevo G3 QTOF mass spectrometer (Waters) with a ACQUITYTM Premier HSS T3 1.8 µm VanGuardTM FIT 2.1 x 150 mm column (Waters). Data collection was performed with negative electrospray ionization (ESI) mode using the MSE method to produce fragment ions when applicable. Repeatability, reproducibility, and carryover were assessed using the QC materials. The analytical measuring range (AMR) was assessed using synthetic urine spiked with increasing concentrations of each organic acid. Accuracy was assessed by method comparison with the UOA test performed at Mayo Clinic Laboratory and by spike-recovery study using a pooled urine specimen. Matrix effect was also evaluated with matrix dilution study. Results An optimized LC method was used to enable high-resolution separation of selected UOAs (N = 29) and isomers. Total analytical time was 20 min per injection. Both linear and quadratic regressions were used to build the calibration curves. AMR and correlation coefficients of a few representative UOAs were: orotic acid (3.4 to 214.2 mmol/mol creatinine, R^2 = 0.99, linear regression); 2-methylcitric acid (4 to 189 mmol/mol creatinine, R^2 = 0.99, linear regression); 3-methylcrotonylglycine (0.3 to 18.0 mmol/mol creatinine, R^2 = 0.99, linear regression). Repeatability and reproducibility were mostly &amp;lt;=10% CV and no carryover was observed. Spike-recovery study demonstrated recoveries between 80% and 120%, and method comparison study demonstrated no discrepancies with results from Mayo Clinic Laboratory. Conclusions We have developed and validated a novel UPLC-QTOF method for UOA analysis to support the diagnosis of IEMs with acceptable analytical and clinical performances. Compared with the traditional GC-MS method, the UPLC-QTOF method requires a very small specimen volume and does not require laborious and time-consuming sample preparation steps. Continued optimization of the method will be pursued to measure more UOAs to support the diagnosis of more IEMs.

Ultrahigh-Performance Supercritical Fluid Chromatography-Mass Spectrometry in the Clinical Lipidomic Analysis.

Ultrahigh-performance supercritical fluid chromatography-mass spectrometry (UHPSFC/MS) method is optimized for the high-throughput quantitation of lipids in human serum and plasma with an emphasis on robustness and accurate quantitation. Bridged ethylene hybrid (BEH) silica column (100×3mm; 1.7μm) is used for the separation of 17 nonpolar and polar lipid classes in 4.4min using the positive ion electrospray ionization mode. The lipid class separation approach in UHPSFC/MS results in the coelution of all lipid species within one lipid class in one chromatographic peak, including two exogenous internal standards (IS) per lipid class, which provides the optimal conditions for robust quantitation. The method was validated according to European Medicines Agency and Food and Drug Administration recommendations. UHPSFC/MS combined with LipidQuant software allows a semiautomated process to determine lipid concentrations with a total run time of only 8min including column equilibration, which enables the analysis of 160 samples per day.

Investigating the chemical space coverage of multiple chromatographic and ionization methods using non-targeted analysis on surface and drinking water collected using passive sampling

Multiple non-targeted analysis tools were used to look for a broad range of possible chemical contaminants present in surface and drinking water using liquid chromatography separation and high-resolution mass spectrometry detection, including both quadrupole time of flight (Q-ToF) and Orbitrap instruments. Two chromatographic techniques were evaluated on an LC-Q-ToF with electrospray ionization in both positive and negative modes: (1) the traditionally used reverse phase C18 and (2) the hydrophilic interaction liquid chromatography (HILIC) aimed to capture more polar contaminants that may be present in water. Multiple ionization modes were evaluated with an LC-Orbitrap, including electrospray (ESI) and atmospheric pressure chemical ionization (APCI), also in both positive and negative modes. A suspect screening library of over 1300 possible environmental contaminants, including pesticides, pharmaceuticals, personal care products, illicit drugs/drugs of abuse, and various anthropogenic markers was made with experimentally collected data with the LC-Q-ToF with both column types, with 227 chemicals being retained by the HILIC column. The non-targeted methods using multiple chromatographic and ionization modes were applied to environmental water samples collected with polar organic chemical integrative samplers (POCIS), including surface water upstream and downstream from wastewater effluent discharge, and the downstream drinking water intake and treated drinking water for three distinct sampling events. For the LC-Q-ToF, 442 chemical features were detected on the C18 column and 91 with the HILIC column in the POCIS extracts, while 556 features were found on the Orbitrap workflow by ESI and 131 features detected by APCI. Over 100 chemicals were tentatively identified by suspect screening and database searching. The comprehensive and systematic evaluation of these methods serve as a step in characterizing the chemical space covered when utilizing different chromatography and ionization methods, or different instrument workflows on complex environmental mixtures.

Improved Astrophysical and Computational Oscillator Strengths for Ultraviolet P ii Lines

Abundance measurements for the volatile element phosphorus are important for measuring the metallicity in interstellar and circumgalactic gas, where their accuracies are limited by uncertainties in the oscillator strengths. We report updated oscillator strength values for two resonant transitions of the dominant ion P II, the transitions at 961.041 and 963.801 Å, which have historically shown large uncertainties. Using a combination of observational measurements and highly accurate quasi-relativistic Hartree–Fock theoretical calculations, we present an updated oscillator strength of f = 0.147 ± 0.021 for the poorly constrained P II resonant transition at 961.401 Å, which arises from the ground electronic state 3s 23p 2 3P0 to the excited level 3s 23p3d 3D 1o . This result utilizes archival optical spectra obtained with the Very Large Telescope for the quasar PKS 0528–250, which has a damped Lyα absorber at z = 2.811. We calculate a theoretical f-value = 0.153 for 961.401 Å consistent with our empirically derived value, and calculate a theoretical f-value = 1.79 for 963.801 Å. We also present theoretical oscillator strengths for the P II resonant transitions at 972.779, 1124.945, 1152.818, 1301.874, and 1532.533 Å, as well as for multiple P II fine-structure and excited-level transitions. The updated f-value for the P II 961 Å transition will be useful in future studies of P abundances, especially in sight lines where the 1152 Å line is saturated.