Mass Spectrometry Equipment Research Articles

12260 Assessing The Impact Of Saliva Collection Devices On Analyte Recovery

Abstract Disclosure: D. Marshall: None. M. Dolan: None. M. Mctaggart: None. B.G. Keevil: None. Introduction: Analysis of saliva is gathering momentum, often conveying advantages over regular venepuncture, offering a convenient way of collecting multiple samples throughout the day with relative ease from the comfort of a patient’s home or workplace. The advent of more sensitive mass spectrometry equipment has opened the possibility of measuring analytes previously unsuitable, offering a multitude of steroid hormones for diagnosis and monitoring of a range of endocrine disorders. Traditionally, samples are collected onto a Sarstedt Salivette device comprising of a synthetic swab enclosed within a polypropylene tube. For certain analytes, the Salivette device is known to impede analyte recovery, resulting in the requirement for a passive drool sample which can be difficult and unpleasant to collect for some patients. Methods Previous work has been undertaken showing the SalivaBio Oral Swab (SOS) to have less of an impact on analyte recovery. Here, through addition of low, medium and high spikes and subsequent LC-MS/MS analysis of 19 different steroid hormones (11-dehydrocorticosterone, 11-deoxycorticosterone, 11-deoxycortisol, 11-hydroxyandrostenedione, 11-hydroxytestosterone, 11-ketoandrostenedione, 11-ketotestosterone, 17-hydroxyprogesterone, 18-hydroxycortisol, 18-oxocortisol, 21-deoxycortisol, aldosterone, androstenedione, corticosterone, cortisol, cortisone, dexamethasone, testosterone and tetrahydro11-deoxycortisol) we aimed to assess a broader repertoire of analytes and whether saliva collection devices impact on analyte recovery. Results With an acceptability criterion of 10% difference from baseline passive drool samples, Salivette devices were acceptable for 12 out of 18 analytes, SOS were acceptable for 16 analytes. Both devices were unacceptable for measurement of androstenedione, testosterone and 11-deoxycorticosterone. When 10% is deemed as an acceptable difference, the SOS performs better than the Salivette device for the steroid hormones investigated in this study. This may have implications for research studies, patient diagnosis and monitoring of endocrine disorders where saliva collection devices were previously deemed unacceptable due to issues with analyte recovery. Presentation: 6/2/2024

Phosphatidylethanol is a promising tool for screening alcohol consumption during pregnancy.

Prenatal alcohol exposure (PAE) is one of the leading causes of preventable developmental disabilities. A lack of objective screening methods results in an under-recognition of the phenomenon. Phosphatidylethanol (PEth) is a specific ethanol biomarker that reveals alcohol intake up to several weeks after alcohol use. So far, PEth has mostly been a tool for detecting moderate and heavy drinking. With lower PEth cut-offs, revealing even minor prenatal alcohol consumption is possible. We aimed to find out if a sensitive method for PEth analysis would give additional information about PAE and to assess the cut-off value for a positive alcohol result in prenatal screening. The study was an observational study of 3000 anonymous blood samples collected from the Helsinki University Hospital Diagnostic Center between June and September 2023. The Finnish Red Cross Blood Service received the samples originally for blood group typing and antibody screening as part of the prenatal blood screening program. We developed a sensitive PEth 16:0/18:1 analysis method using ultra-high-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) equipment after liquid-liquid extraction of PEth from whole blood. The lower limit of quantification was 1 ng/mL. PEth was ≥2 ng/mL in 5.2% of the cases, ≥8 ng/mL in 2.0%, and ≥20 ng/mL in 1.0%. The detection time of PEth can be several weeks, especially with low PEth concentrations and after heavy alcohol consumption. It remained unknown whether the positive PEth tests resulted from drinking deliberately during pregnancy or before pregnancy recognition. We suggest adding PEth 16:0/18:1 to a routine prenatal blood screening program with a cut-off of 2 ng/mL-and in positive cases, clinical evaluation and retesting in 2-4 weeks. In clinical settings, information on gestational week and alcohol consumption before pregnancy is relevant and needs to be considered when interpreting low PEth concentrations.

Measuring fecal neurotransmitter concentrations using Dried Fecal Spot (DFS)-based LC-MS/MS bioanalysis

Background: Guthrie implemented dried blood spot (DBS)-based bioanalytical techniques in the 1960s in order to screen for phenylketonuria (PKU) disease in neonates. Historically, the dominant matrix analyzed using the “Guthrie card” platform has been whole blood, but recent advances in device technology now allow for whole blood-to-plasma sample processing prior to drying and subsequent bioanalysis. This project aimed to use this dried matrix technologies in an entirely new direction by performing dried fecal spot (DFS)-based bioanalysis for analytical microbiology and microbiome applications. Homogenized fecal sample extracts were loaded onto quantitative DBS (qDBS) devices and were allowed to dry overnight, then were shipped at ambient shipping temperature. The DBS spots were processed and subjected to LC-MS/MS-based targeted metabolomics using our Glutamate Cycle method (Glu, Gln, and GABA). Methods & Results: Fecal samples were collected from each of the five human subjects enlisted in the following cohorts: 1) healthy controls; 2) patients with diarrhea; and, 3) Clostridioides diffcile-infected (CDI) patients. A volume of ice-cold methanol:water (1:1, v:v) equivalent to a fecal density of 50 mg/mL was added into individual homogenization tubes that each contained 100 mg of 1.4 mm silica beads. Fecal samples were homogenized using 5 bead-beating cycles (4 m/s for each 20 s pulse). After centrifugation (@500 g), a 20-μL sample supernatant volume was loaded onto qDBS devices that yielded an exact 10-μL DFS spot volume on the embedded cards. Dried DFS spots were removed from the device and homogenized in a 200-μL volume of an IS solution. The Glu, Gln, and GABA concentration of each sample was compared against the concentrations measured in the matched frozen fecal extracts. We were able to successfully detect GABA in both the standard extraction method and in our processed DFS samples. Interestingly, we observed large variability between patient samples and there were no statistically significant differences between the cohorts. Conclusion: Collectively, these data demonstrate the utility of our method for measuring the concentrations of Glu, Gln and GABA contained in our processed DFS-based sample sets. This study was supported by the NIH K01K123195-01 (MAE). The Texas Children’s Hospital Department of Pathology provides salary support to Texas Children’s Microbiome Center-Metabolomics Lab staff, and purchased all of the reagents, the consumables and durable supplies, and the liquid chromatography-tandem mass spectrometry (LC-MS/MS) equipment described. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Recent Developments and Application of Mass Spectrometry Imaging in N-Glycosylation Studies: An Overview.

Among the most typical posttranslational modifications is glycosylation, which often involves the covalent binding of an oligosaccharide (glycan) to either an asparagine (N-linked) or a serine/threonine (O-linked) residue. Studies imply that the N-glycan portion of a glycoprotein could serve as a particular disease biomarker rather than the protein itself because N-linked glycans have been widely recognized to evolve with the advancement of tumors and other diseases. N-glycans found on protein asparagine sites have been especially significant. Since N-glycans play clearly defined functions in the folding of proteins, cellular transport, and transmission of signals, modifications to them have been linked to several illnesses. However, because these N-glycans' production is not template driven, they have a substantial morphological range, rendering it difficult to distinguish the species that are most relevant to biology and medicine using standard techniques. Mass spectrometry (MS) techniques have emerged as effective analytical tools for investigating the role of glycosylation in health and illness. This is due to developments in MS equipment, data collection, and sample handling techniques. By recording the spatial dimension of a glycan's distribution in situ, mass spectrometry imaging (MSI) builds atop existing methods while offering added knowledge concerning the structure and functionality of biomolecules. In this review article, we address the current development of glycan MSI, starting with the most used tissue imaging techniques and ionization sources before proceeding on to a discussion on applications and concluding with implications for clinical research.

Quantification of fluticasone propionate in human plasma by LC–MS/MS and its application in the pharmacokinetic study of nasal spray at clinical doses

We developed a method for quantifying fluticasone propionate (FP) using general-purpose liquid chromatography–tandem mass spectrometry equipment to measure the plasma concentration of FP for the pharmacokinetic study of FP following the administration of a prescribed nasal spray dose (100 μg). Using ammonium acetate (0.01 M)–formic acid (pH 2.9; 499:1, v/v) and methanol as the mobile phase, 3 pg/mL of FP was quantified. The relative error and standard deviation of the lower limit of quantification were <3.1%. The intra- and interday assay reproducibility was <3.5%. After 15 min of administering 200 μg FP nasal spray as the first dose, the FP concentration detected in the plasma of the two participants was 3.99 and 3.69 pg/mL. Subsequent doses of 100 μg FP were administered twice daily. The area under the plasma concentration–time curve values after 8–10 days of repeated administration of 100 μg of FP were approximately 1.6-fold higher than those achieved following a single administration of 200 μg of FP, which confirmed drug accumulation. The bioavailability of nasal FP was estimated to be 2% and 4%. This knowledge might help in reducing anxiety among patients who avoid using FP nasal spray, fearing its adverse effects.

Identifying therapeutic monoclonal antibodies using target protein collision electrophoresis reflex assay to separate the wheat from the chaff

Monoclonal gammopathies are characterized by the presence of monoclonal immunoglobulins, also known as M-proteins. Therapeutic monoclonal antibodies (t-mAbs) can interfere in laboratory assays used to monitor the state of disease, such as serum protein electrophoresis (SPE) and immunofixation electrophoresis (IFE). To establish a correct interpretation of IFE, Target protein-Collision Immunofixation Electrophoresis Reflex Assay (T-CIERA) was developed to identify t-mAbs in IFE. Here we demonstrate that T-CIERA is applicable to a wide variety of t-mAbs for which the target protein is commercially available. Moreover, the shift observed was characteristic for each t-mAb, and T-CIERA enabled the identification of multiple t-mAbs sharing a common target protein. Additionally, the lower limit of detection (LLOD) was determined objectively, and T-CIERA demonstrated an adequate LLOD for all tested t-mAbs. Furthermore, T-CIERA was also successfully applied to serum samples obtained from patients receiving daratumumab, isatuximab, elotuzumab, and durvalumab treatment. In conclusion, T-CIERA is a suitable reflex assay for identifying a wide variety of t-mAbs, including those for which no commercial assay is available to deal with their interference. Moreover, CD38-CIERA could serve as an alternative or complementary test to the commercially available Hydrashift assay kits. T-CIERA would enable laboratories without mass spectrometry equipment and expertise in this area to distinguish between drug and disease to improve clinical response monitoring and diagnosis of monoclonal gammopathies.

Optimisation of the analysis procedure of polybrominated diphenyl ethers (PBDEs) in plastic waste from household products

Polybrominated diphenyl ethers (PBDEs) are one group of flame retardants used as additives in many household products, in-cluding plastic products. Determining the residues of PBDEs in household plastic products is required to control their effects on human health and leach into the environment after disposal. This study was conducted to optimise sample preparation conditions for analysing PBDEs in plastic waste from household products. The study results are given that the instrument detection and quantification limits (IDL and IQL) ranged from 4.19 to 28.4 ppb and 14.0 to 94.8 ppb, respectively. In addition, the method detec-tion limit (MDL) and method quantification limit (MQL) were the lowest at 2.20 and 7.35 ng/g (BDE 99) and the highest at 24.1 and 80.3 ng/g (BDE 209), respectively, while the recovery val-ues for spiking samples at different concentrations ranged from 89.1 to 104.5%. The results of the method validation can confirm that the soxhlet extraction and solid phase extraction (SPE) tech-niques combined with gas chromatography mass spectrometry (GC/MS) equipment can be applied to determine the PBDEs in plastic waste samples.

Optimisation of LDI(+)-FT-ICR MS analysis of asphaltenes to prevent the formation of fullerenes

The laser desorption and ionisation (LDI) technique coupled with mass spectrometry (MS) equipment is a common tool for determining the chemical composition of asphaltene molecules chemical composition of asphaltene molecules. However, the laser radiation that impacts the sample can lead to the formation of fullerene artifacts, which has generated numerous controversies. In this work, we employed a 2(6-2) fractional factorial design and central composite design to optimise the assay of the positive-ion mode LDI technique coupled with Fourier transform ion cyclotron resonance mass spectrometry (LDI(+) FT-ICR MS) for analysing asphaltenes, aiming to avoid the formation of fullerenes during ionisation. We evaluated the experimental conditions such as: analyte concentration, number of shots, power, frequency and focus. Subsequently, we analysed the same asphaltene sample using the positive mode-ion atmospheric pressure photoionisation ionisation (APPI(+)) technique to compare and complement the data obtained using the LDI(+) technique. We found that higher values of power and focus, as well as their interaction at a high level, favoured effective ionisation of asphaltenes, without the formation of artifacts such as fullerenes. Additionally, minimal focus favoured the formation of fullerenes, which were identified starting at m/z 528 Da (C44) to m/z 1488 (C124). After optimisation, LDI(+) identified 1,486 polar compounds and five classes (HC; N; N2; N4[H]; and N4O4[H] classes). In comparison, the APPI(+) technique identified only 307 polar compounds and the same number of classes (HC[H]; HC; N[H]; O[H]; and S classes). These data demonstrate that LDI(+) technique has a greater ability to ionise nitrogen compounds.

Evaluation of macro, micro, and toxic minerals in Dates fodder in Basra, Southern Iraq‏

Mineral concentrations in plants are affected by a number of factors, which in turn affect the amounts available directly or indirectly to animals, so the concentration of some nutrients may be insufficient for the needs of animals. The article aimed to evaluate a wide variety of chemical elements in date fodder often used to feed cows, buffaloes, and sheep in Basra Governorate, Southern Iraq. In addition, it establishes the acceptability of chemical element concentrations in the dates, which included macro-minerals, micro-elements, and hazardous metals. The feed was prepared to be digested and then all minerals were analyzed using Inductively Coupled Plasma Mass Spectrometry (ICP-MS) equipment to determine the amounts of macro-minerals, micro-elements, and hazardous elements in the feed. Where macro-minerals included (calcium, magnesium, phosphorus, potassium, sodium, and sulfur) and micro-elements included (iron, copper, nickel, selenium, chromium, tin, silicon, vanadium, and molybdenum, while toxic elements included (aluminium, arsenic, cadmium, uranium, and lead). Most major and minor elements had low values compared to the critical level determined for their presence in fodders, as all elements did not reach the maximum tolerable(4.5% of macro-minerals and 40 ppm of micro-elements) and much less than the minimum limit(&lt;0.06 of macro-minerals and &lt;0.20ppm of micro-elements), whereas the toxic elements in the chosen dates fodder had low and acceptable concentrations compared to the risk index for their presence in fodder(100 mg Kg-1). The current study helps farmers in Basra Governorate in their understanding of the mineral nutritional needs of cattle while relying significantly on this type of fodder.

Bringing synapses into focus: Recent advances in synaptic imaging and mass-spectrometry for studying synaptopathy.

Synapses are integral for healthy brain function and are becoming increasingly recognized as key structures in the early stages of brain disease. Understanding the pathological processes driving synaptic dysfunction will unlock new therapeutic opportunities for some of the most devastating diseases of our time. To achieve this we need a solid repertoire of imaging and molecular tools to interrogate synaptic biology at greater resolution. Synapses have historically been examined in small numbers, using highly technical imaging modalities, or in bulk, using crude molecular approaches. However, recent advances in imaging techniques are allowing us to analyze large numbers of synapses, at single-synapse resolution. Furthermore, multiplexing is now achievable with some of these approaches, meaning we can examine multiple proteins at individual synapses in intact tissue. New molecular techniques now allow accurate quantification of proteins from isolated synapses. The development of increasingly sensitive mass-spectrometry equipment means we can now scan the synaptic molecular landscape almost in totality and see how this changes in disease. As we embrace these new technical developments, synapses will be viewed with clearer focus, and the field of synaptopathy will become richer with insightful and high-quality data. Here, we will discuss some of the ways in which synaptic interrogation is being facilitated by methodological advances, focusing on imaging, and mass spectrometry.

Overview of Status of Medical Device Registration and Quality Evaluation Requirements for Clinical Mass Spectrometry

Mass spectrometry technology is becoming an important tool for clinical analysis due to its high specificity, high sensitivity and high multi-component detection capability. The current applications of this technology are mainly in liquid chromatography-tandem mass spectrometry (LC-MS/MS), matrix-assisted laser desorptionionization time-of-flight mass spectrometry (MALDI-TOF-MS), inductively coupled plasma mass spectrometry (ICP-MS), gas chromatography-mass spectrometry (GC-MS) and the related in vitro diagnostic kits. At present, the number of medical device (MD) based on mass spectrometry technology is growing rapidly, especially the number of LC-MS/MS and MALDI-TOF-MS registered MD products, and the standardization of relevant product quality requirements is also being effectively carried out. In general, clinical mass spectrometry equipment is still mainly imported, and the equipment price is relatively high. The development of mass spectrometry kits is mainly based on imported platforms, and domestic equipment is still in its infancy; the further promotion of clinical application of mass spectrometry also depends on the progress of the automation and standardization of the analysis procedure. To investigate the detection performance of mass spectrometry systems, it is necessary to fully consider the characteristics of mass spectrometry technology itself.

Factorial design applied to LC-ESI-QTOF mass spectrometer parameters for untargeted metabolomics.

Investigations of untargeted metabolomics are based on high-quality data acquisition usually from multiplatform systems that include high-resolution mass spectrometry equipment. The comprehensive set of results is used as data entry for bioinformatics and machine learning sciences to access reliable metabolic and biochemical information for clinical, forensic, environmental, and endless applications. In this context, design of experiments is a powerful tool for optimizing data acquisition procedures, using a multivariate approach, which enables the maximization of a high-quality amount of information with reduced number of tests. In this study, we applied a 33 Box-Behnken factorial design with central point triplicate for optimizing the ionization of an HPLC-ESI-QTOF method used for screening urine samples. Nozzle voltage (V), fragmentor voltage (V) and nebulizer pressure (psig) were the factors selected for variation. The response surface methodology was applied in the molecular features extracted at each level, resulting in a statistical model that helps evaluating the synergic interaction between these factors. Together with the qualitative analysis of the resulting total ion chromatograms, we came across a reproducible (6.14% RSD) and highly efficient method for untargeted metabolomics of human urine samples. The proposed method can be useful for applications in several urine-based metabolomics-driven studies, as the factorial design can be applied in the development of any analytical protocol considering different LC-MS setups.

Qualitative and quantitative determination of butanol in latex paint by fast gas chromatography proton transfer reaction mass spectrometry

Butanol is a common organic solvent used in latex paint, and one of its isomers, tert-butanol, is toxic and can cause potential harm to the human body. Therefore, it is of great significance to develop a qualitative and quantitative detection method for butanol isomers. In this study, we combined the advantages of rapid detection of proton transfer reaction mass spectrometry (PTR-MS) with the separation and qualitative capabilities of gas chromatography-mass spectrometry (GC-MS) to achieve the detection of isomers, building a fast gas chromatography proton transfer reaction mass spectrometry (FastGC-PTR-MS) equipment. Firstly, the developed technology was optimized using standard samples of several common volatile organic compounds. The retention times of acetonitrile, acetone, and alcohols were less than 50 s, and the retention times of the benzene series were less than 110 s, on the premise that these isomers could be basically separated (resolution R > 1.0). Compared with a commercial GC-MS equipment, the detection times were shortened by 5-6 times and 2-4 times, respectively. Then the FastGC-PTR-MS was applied to detect the isomers of butanol in latex paint. The results showed that the headspace of brand D latex paint mainly contained five substances: tert-butanol, n-butanol, acetaldehyde, methanol, and acetone. Tert-butanol and n-butanol could be completely separated (R > 1.5). The concentration of tert-butanol was 4.41 ppmv, far below the 100 ppmv maximum allowable workplace concentration. The developed FastGC-PTR-MS can be used for rapid qualitative and quantitative detection of butanol isomers in latex paint. The new equipment has the potential to play an important role in indoor environmental safety applications.

Laboratory investigation of pheromone pre‐exposure in Lobesia botrana males indicates minor role of desensitization in the field

AbstractThe role of desensitization in mating disruption (MD) of European Grapevine Moth (EGVM), Lobesia botrana (Dennis and Schiffermüller) (Lepidoptera: Tortricidae), is studied by exposing males to different airborne pheromone concentrations for various time intervals prior to evaluate their behavioural response. By using different types of dispensers, male moths are exposed to three decreasing pheromone concentrations (up to the minimum concentration able to desensitize them) for 1, 3, and 24 h. The airborne pheromone concentration present in all treatments is accurately quantified using gas chromatography–mass spectrometry equipment to compare these data with actual airborne pheromone concentrations under field conditions. The effect of pheromone exposure on L. botrana males is studied in wind tunnel and electroantennogram assays, immediately and 24 h after the exposure period. Results show that the reduction of response to the pheromone depended on the dose and the duration of the treatment, but the lowest dose tested did not produce desensitization. These results support that the most important mechanisms of MD acting in fields treated against EGVM are the competitive ones and that the non‐competitive ones only may become relevant very close to pheromone dispensers. Our results support the hypothesis of cross‐adaptation to other chemical stimuli in the pre‐exposed moths to their pheromone although more studies are needed to draw stronger conclusions.

Practical considerations for improved reliability and precision during determination of δ15 N values in amino acids using a single combined oxidation-reduction reactor.

There has been increased interest in the measurement of δ15 N values in amino acids (AAs) to gain simultaneous insight into both trophic relationships and the composition of biogeochemical sources used by producers at the base of the food web. A new combustion reactor design in gas chromatography/combustion isotope ratio mass spectrometry (GC/C-irMS) equipment has brought to light variable outcomes in performance, highlighting the need for better information about best practices for new systems. Precision for δ15 N values in amino acids using the single combined oxidation-reduction reactor is improved across a sequence of analyses if the reactor is oxidized for a substantial period (2 h) and subsequently maintained throughout the sequence with 12-17 s seed oxidation before each run during GC/C-irMS. A five-point calibration curve using amino acids with a range of δ15 N values from -2.4‰ to +61.5‰ was used in combination with a 13-15 amino acid mixture to consistently normalize measurements to internationally calibrated reference materials. Combining this oxidation method with normalization techniques using both internal and external standards provided a reliable throughput of ~25 samples per week. It allowed for a reproducible level of precision of <±0.5‰, n = 10 within a derivatized standard mixture across each sequence and an average sample precision of ±0.27‰ n = 3, which is lower than the analytical precision typically associated with δ15 N values for amino acid analysis (<±1‰). A few practical considerations regarding oxidation and conditioning of the combustion reactor allow for increased sequence capacity with the single combined oxidation-reduction reactor. These considerations combined with normalization techniques result in a higher throughput and reduced analytical error during the measurement of δ15 N values in amino acids.

Quantification by Ultrafiltration and Immunofixation Electrophoresis Testing for Monoclonal Serum Free Light Chains.

Measurement of monoclonal immunoglobulins is a reliable estimate of the plasma cell tumor mass. About 15% of plasma cell myelomas secrete light chains only. The concentration of serum free light chains is insufficient evidence of the monoclonal light chain burden. A sensitive quantitative estimate of serum free monoclonal light chains could be useful for monitoring patients with light chain myeloma. We describe such an assay that does not require mass-spectrometry equipment or expertise. Serum specimens from patients with known light chain myelomas and controls were subjected to ultrafiltration through a membrane with pore size of 50 kDa. The filtrate was concentrated and tested by immunofixation electrophoresis. The relative area under the monoclonal peak, compared to that of the total involved light chain composition, was estimated by densitometric scanning of immunofixation gels. The proportion of the area occupied by the monoclonal peak in representative densitometric scans was used to arrive at the total serum concentration of the monoclonal serum free light chains. Using an ultracentrifugation and concentration process, monoclonal serum free light chains were detectable, along with polyclonal light chains, in all 10 patients with active light chain myelomas. Monoclonal light chains were identified in serum specimens that did not reveal monoclonal light chains by conventional immunofixation electrophoresis. The limit of detection by this method was 1.0 mg/L of monoclonal serum free light chains. The method described here is simple enough to be implemented in academic medical center clinical laboratories and does not require special reagents, equipment, or expertise. Even though urine examination is the preferred method for the diagnosis of light chain plasma cell myelomas, measurement of the concentration of serum free light chains provides a convenient, albeit inadequate, way to monitor the course of disease. The method described here allows effective electrophoretic differentiation of monoclonal serum free light chain from polyclonal serum free light chains and provides a quantitation of the monoclonal serum free light chains in monitoring light chain monoclonal gammopathies.

Urine colorimetry for levofloxacin pharmacokinetics and personalized dosing in people with drug-resistant tuberculosis.

Background:Levofloxacin is a preferred drug for multidrug-resistant (MDR)-tuberculosis (TB) with bactericidal activity that correlates with the pharmacokinetic exposures of serum peak concentration (Cmax) and total area under the concentration time curve (AUC0-24). Pharmacokinetic exposures can be measured to personalize dosing to reach targets, but this practice requires venepuncture, chromatographic or mass spectrometry equipment, and technical expertise. We sought to demonstrate the accuracy of using urine colorimetry as a more feasible estimation of levofloxacin exposure.Method:A colorimetric method using bromocresol green was tested on spiked urine samples with levofloxacin measured using a spectrophotometer. This method was tested in urine samples of healthy volunteers given one 750 mg dose of levofloxacin with urine collected at 0–4 h, 4–8 h, and 8–24 h intervals, and concomitant serum samples were collected and analyzed by high-performance liquid chromatography. Validation of this assay was done in a cohort of people living with human immunodeficiency virus (PLWH), initiating a levofloxacin containing MDR-TB regimen.Results:Urine colorimetry was reproducible in spiked samples and the calibration was curve linear for levofloxacin concentrations ranging from 7.8 μg/ml to 250 μg/ml, with r = 0.98. In healthy volunteers, correlation between urine absorbance values and serum AUC0-24 was highest in urine collected between 4 and 8 h (r = 0.91, P = 0.01), yet in PLWH, urine collected between 0 and 4 h had highest correlation (r = 0.66, P = 0.05). The area under the receiver operating characteristics curve was >0.8 in the derivation, as well as the validation cohort for the urine absorbance values identifying people with total serum exposure below target.Conclusion:Urine colorimetry was highly sensitive in predicting target serum concentrations. Colorimetric methods to determine levofloxacin in urine may improve the feasibility of therapeutic drug monitoring and personalized dose adjustment in TB endemic settings.

Understanding Improvements to Low-Temperature Rheology of Stiff Binders Modified with Epoxidized Plant–Derived Oil Materials through Analytical Chemistry

Abstract Through recent work at Iowa State University, great potential was seen from epoxidized plant oil materials, epoxidized benzyl soyate (EBS), and epoxidized methyl soyate (EMS) as fluxes/rejuvenators. This work found that improvement in low-temperature performance was greater than improvement in high-temperature performance for solvent de-asphalting (SDA) and residuum oil super critical extraction (ROSE) unit bottoms when using either EBS or EMS as compared to results from modified vacuum distillation tower bottoms with EBS and EMS. Based on these results, analytical chemistry was done using Fourier transformed infrared with attenuated total reflection and ion mobility mass spectrometry (IM-MS) equipment. Chemical analysis showed that there is indeed something in the SDA and ROSE binders that is interacting with both EBS and EMS, making them perform aggressively. The region of interest was identified from IM-MS to be between m/z 250 and m/z 400 for the SDA and ROSE binders, of which there were 35 common components where 29 of them had similar abundances in the SDA and ROSE binders.

Acquisition of Mass Spectrometry Data of Carotenoids: A Focus on Big Data Management.

Accurate determination of carotenoid profile in plant tissues and food samples requires the application of hyphenated analytical resources including HPLC with high-resolution hybrid mass spectrometers. The high analytical power of modern MS equipment means the generation of Big Data resulting from the independent and complementary physicochemical properties of the target compounds that requires a complex processing to unravel the results. The present protocol describes a complete pipeline methodology for high-throughput analysis of carotenoids based on mass spectrometry (MS). After an exhaustive extraction, the workflow includes the acquisition of HPLC-hr-MS and MS2 spectra assisted step by step by specific post-processing software.

HEMPSEED AND COTTONSEED OILS IN THE ACCESSIONS FROM THE VIR COLLECTION AS SOURCES OF FUNCTIONAL FOOD INGREDIENTS

Background. Oils of hemp and cotton presently have reduced retail trade offer in Russia, but are widely produced and used. Industrial hemp is still cultivated and processed domestically. In the 1950s, industrial cotton was cultivated on a hundred thousand hectares in the country, and now there are signs of its restored growing. Both crops have the ability to restore the raw material base to produce textile fibers, seed and oil as well as the potential to improve functional food production, because they contain functional food ingredients in their oil capable of reducing human nutrition disorder risks, preventing or restoring nutrient deficiencies, preserving and improving health.Materials and methods. Unsaturated and polyunsaturated fatty acids’ profiles of hempseed (Cannabis sativa L.) and cottonseed (Gossypium hirsutum L., G. herbaceum L., G. barbadense L.) oils were evaluated. Seeds were grown respectively under the conditions of the Russian North-West (hemp) and Adler District, Krasnodar Territory (cotton). The PUFA profile was measured using gas chromatography with mass spectrometry equipment (Agilent 6850, USA). All data were calculated using the UniChrom software.Results and conclusions. The content of the omega-6 linoleic acid in hemp accessions reached 64.2%; omega-3 alpha-linolenic acid, 27.1%; monounsaturated oleic acid, 14.0%. The sum of unsaturated acids was 94.2%; and that of polyunsaturated ones, 87.2%. Compared with hemp oil, cotton oil had a lesser sum of polyunsaturated (maximum 58.0%) acids, while its unsaturated acids were up to 79.0%. Oleic acid was found to reach 22.7% in cottonseed oil. Industrial cultivation of hemp and cotton in Russia need not be limited to textile fiber production, but may serve as a potential base of vegetable oils and food; just because of their PUFA contents, it is promising for the production of functional food ingredients, which have health benefits in reducing the risk of cancer and cardiovascular diseases, lowering the HDL cholesterol levels, and relaxing the smooth muscle cells in arteries, thus increasing the blood flow. Seed cake may be valuable addition to animal feed rations as well. As a result of the evaluations, valuable accessions (cultivars and lines) of hemp and cotton were identified. Although the selected accessions are not the products of previous breeding efforts aimed at the PUFA content improvement, they are promising source materials for the development of new cultivars with seeds enriched with compounds or sets of compounds that provide a beneficial effect on human health when included in the composition of food products (functional food ingredients).