Optimisation and validation of a GC-MS method for screening for diuretics in adulterated weight loss dietary supplements

Threshold fluences for production of positive and negative ions in matrix-assisted laser desorption/ionisation using liquid and solid matrices

This is the first study presenting a multi-residue method allowing for comprehensive analysis of several chiral pharmacologically active compounds (cPACs) including beta-blockers, antidepressants and amphetamines in wastewater and digested sludge at the enantiomeric level. Analysis of both the liquid and solid matrices within wastewater treatment is crucial to being able to carry out mass balance within these systems. The method developed comprises filtration, microwave assisted extraction and solid phase extraction followed by chiral liquid chromatography coupled with tandem mass spectrometry to analyse the enantiomers of 18 compounds within all three matrices. The method was successfully validated for 10 compounds within all three matrices (amphetamine, methamphetamine, MDMA, MDA, venlafaxine, desmethylvenlafaxine, citalopram, metoprolol, propranolol and sotalol), 7 compounds validated for the liquid matrices only (mirtazapine, salbutamol, fluoxetine, desmethylcitalopram, atenolol, ephedrine and pseudoephedrine) and 1 compound (alprenolol) passing the criteria for solid samples only. The method was then applied to wastewater samples; cPACs were found at concentration ranges in liquid matrices of: 1.7ngL−1 (metoprolol) – 1321ngL−1 (tramadol) in influent, <LOD (desmethylcitalopram and metoprolol) – 506ngL−1 in effluent, and in solid matrix digested sludge: 0.4ngg−1 (metoprolol) – 275ngg−1 (citalopram). Enantiomeric profiling revealed that studied compounds were present in analysed samples in non-racemic composition. Furthermore, enantiomeric composition of studied analytes differed in liquid and solid matrices. This demonstrates that not analysing the solid fraction of wastewater may lead to over-estimation of the removal rates of cPACs as well as possible misrepresentation of the enantiomeric fraction of the compounds as they leave the wastewater treatment plant. Consequently risks from cPACs entering the environment might be higher than anticipated.

Validated quantification method for five ephedrines in dietary supplements using LC-MS/MS: Application to 503 cases.

Matrix-assisted laser desorption/ionization (MALDI) was performed on individual, size-selected aerosol particles in the 2−8 μm diameter range. Monodisperse aerosol droplets containing matrix, analyte, and solvent were generated and entrained in a dry stream of air. The dried particles were drawn from atmospheric pressure directly into the source region of a reflecting field time-of-flight mass spectrometer. Individual particles were then detected by light scattering and analyzed on-the-fly by MALDI. The particle size and composition were systematically varied, and both liquid and solid matrices were studied. As the analyte-to-matrix mole ratio increased, the analyte signal intensity first increased and then leveled off. Quenching effects were observed when two different peptides were present in the same particle. These dependences were interpreted on the basis of analyte surface activity and adsorption isotherms. With a liquid matrix, the analyte is thought to partition between the particle surface and bulk. The signal intensity increases with analyte surface coverage until a monolayer is formed. With a solid matrix, the analyte is thought to adsorb on the surface of the original droplet containing matrix, analyte, and solvent. When the solvent evaporates, the analyte deposits on the dry particle surface. Again, the signal intensity increases with analyte surface coverage until a monolayer is formed. With either a solid or liquid matrix, signal quenching is observed when multiple analytes compete for surface adsorption.

Although liquid matrix-assisted laser desorption/ionization (MALDI) has been used in mass spectrometry (MS) since the early introduction of MALDI, its substantial lack of sensitivity compared to solid (crystalline) MALDI was for a long time a major hurdle to its analytical competitiveness. In the last decade, this situation has changed with the development of new sensitive liquid matrices, which are often based on a binary matrix acid/base system. Some of these matrices were inspired by the recent progress in ionic liquid research, while others were developed from revisiting previous liquid MALDI work as well as from a combination of these two approaches. As a result, two high-performing liquid matrix classes have been developed, the ionic liquid matrices (ILMs) and the liquid support matrices (LSMs), now allowing MS measurements at a sensitivity level that is very close to the level of solid MALDI and in some cases even surpasses it. This chapter provides some basic information on a selection of highly successful representatives of these new liquid matrices and describes in detail how they are made and applied in MALDI MS analysis.

Stability and recovery of cyclodextrin encapsulated catechin in various food matrices

Aim: The purpose of this study was to obtain data concerning growth factor release within liquid and solid platelet-rich fibrin (PRF) matrices and to estimate the amount of potential interindividual variations as a basis for further preclinical and clinical trials. Therefore, we aimed to determine possible differences in the release of growth factors between liquid and solid PRF. Materials and Methods: Blood samples obtained from four subjects were processed to both liquid and solid PRF matrices using a standard centrifugation protocol. Five growth factors (vascular endothelial growth factor, VEGF; epidermal growth factor, EGF; platelet-derived growth factor-BB, PDGF-BB; transforming growth factor-β1, TGF-β1; and matrix metallopeptidase 9, MMP-9) have been evaluated at six time points by ELISA over a total observation period of 10 days (1 h, 7 h, 1 d, 2 d, 7 d, and 10 d). Results: Growth factor release could be measured in all samples at each time point. Comparing liquid and solid PRF matrices, no significant differences were detected (p > 0.05). The mean release of VEGF, TGFβ-1, PDGF-BB, and MMP-9 raised to a peak at time point five (day 7) in both liquid and solid PRF matrices. VEGF release was lower in liquid PRF than in solid PRF, whereas those of PDGF-BB and MMP-9 were higher in liquid PRF than in solid PRF at all time points. EGF had its peak release already at time point two after 7 h in liquid and solid matrices (hour 7 EGF solid: mean = 180 pg/mL, SD = 81; EGF liquid: mean = 218 pg/mL, SD = 64), declined rapidly until day 2, and had a second slight peak on day 7 in both groups (day 7 EGF solid: mean = 182 pg/mL, SD = 189; EGF liquid: mean = 81 pg/mL, SD = 70). Conclusions: This study detected growth factor release within liquid and solid PRF matrices with little variations. Further preclinical trials are needed to precisely analyze the growth factor release in larger samples and to better understand their effects on wound healing in different clinical indications.

Use of nitrate as a dietary supplement has gained popularity among athletes and recreationally active individuals to enhance exercise performance. However, the prevalence and patterns of use, and knowledge of nitrate as a dietary supplement are unknown. Individuals (≥16y) completed a 42-item online questionnaire to collect (i) sociodemographic information; (ii) participation in activity and sport; (iii) nitrate supplementation use and reasons; (iv) attitudes and beliefs regarding information sources and the safety of nitrate as a dietary supplement; and (v) knowledge of dietary nitrate supplements. In total, 1,404 active adults (66% female) took part in the study. Only about one in 10 respondents (11.9%) reported they had consumed dietary nitrate ("users") in the past, most commonly as beetroot juice (31.3%). Over two-thirds (69.4%) of users could not correctly identify the correct timing of intake relative to performance time to best improve exercise performance, and most users (82.3%) were unsure of the contraindications to oral consumption of dietary nitrate supplements. Only 3.9% of users experienced adverse effects after ingesting dietary nitrate supplements. Among non-users, the most common reasons respondents selected for not using dietary nitrate supplements were "I do not think I need to" (70.2%) and "I have never thought about it" (69.2%). There is evidence to support the efficacy of dietary nitrate intake in improving exercise performance. However, findings from this study suggest dietary nitrate is under-utilized. Educational messages that target dietary nitrate consumption should be targeted toward nutritionists, coaches, and exercise physiologists to bridge the gap between knowledge-to-practice.

Methylated magnetic covalent organic framework for sample preparation and LC-MS/MS detection of 12 tadalafil analogs in dietary supplements

Introduction Nowadays, there is a trend to enrich food and food supplements (FS) with Vitamin D3. Economic operators who places FS on the market does not have to perform running safety trials, but only to comply with the food safety regulations applicable in the European Union [1]. This scenario may present public health and legal issues. To overcome these challenges, it is mandatory to know accurately the amount of vitamin D3 in FS and if it corresponds to the label value. HPLC methods are a preferential approach to determine accurately the content of vitamin D3 in pharmaceuticals and supplements. Actually, HPLC/MS has become the technique of choice for vitamin D3 determination in complex matrixes. Notwithstanding, this analysis must be preceded by time-consuming sample preparation. In fact, the success to measure accurately vitamin D3 depends heavily in a reliable sample preparation. Moreover, it becomes even more critic when dealing with different formulations of vitamin D3, such has gel pills, solid pills, liquid or cutaneous applications. There are literature validating methodology to determinate vitamin D3 in various matrixes according to the International Conference on Harmonisation (ICH) guidelines by HPLC-UV [2]. However, this published study does not use an internal standard (IS). The internal standard is useful to improve the precision of quantitative analysis, removing the error of losing sample during sample preparation. Our aim is to test o-cresol as an internal standard to future validation the methodology. Materials and methods Vit D3 present in FS was analysed by HPLC/DAD. Sample was spiked with internal standard (o-cresol) and liquid extraction coupled to an ultrasound bath was used has an extraction procedure. After a centrifuged step the supernatant was filtered. The separation was performed using a C18 column with a solvent gradient consisted in (A) 0.1% formic acid and (B) acetonitrile. The acquisition was performed on DAD-detector at 265 nm. Results Figure 1 shows a chromatogram of a FS containing Vit D3. Two major peaks are present, corresponding to o-cresol (RT 5.45 min) and Vit D3 (RT 11.20 min). Discussion and conclusions: The results show the capacity of the chromatographic method to separate and resolve the two chromatographic peaks. These preliminary results show that o-cresol can be used as an internal standard to determine Vit D3 in FS, normalising the loss of Vit D3 during preparation step. Since in Europe and USA, the association of vitD toxicity with the use of FS has been described, this methodology will be useful to confirm the VitD composition stated on the label. Figure 1. HPLC/DAD chromatogram of FD with IS (RT = 5.45 min) and Vit D3 (tr = 11.20 min).

The optical properties of single colloidal semiconductor nanoparticles (NPs) are considerably influenced by the direct environment of the NPs. Here, the influence of different liquid and solid glycol matrices on CdSe-based NPs is investigated. Since the fluorescence of individual NPs varies from one NP to another, it is highly desirable to study the very same individual NPs in different matrices. This was accomplished by immobilizing NPs in a liquid cell sample holder or in microfluidic devices. The samples have been investigated by space-resolved wide-field fluorescence microscopy and energy- and time-resolved confocal scanning fluorescence microscopy with respect to fluorescence intensities, emission energies, blinking behavior, and fluorescence decay dynamics of individual NPs. During the measurements the NPs were exposed to air, to liquid ethylene glycols H(OCH2CH2)nOH (also called EGn) with different chain lengths (1 ≤ n ≤ 7), to liquid 2-methylpentane-2,3-diol, or to solid polyethylene oxide. It was found that EG6-7 (also known as PEG 300) is very well suited as a liquid matrix or solvent for experiments that correlate chemical and physical modifications of the surface and of the immediate environment of individual NPs to their fluorescence properties since it leads to intense and stable fluorescence emission of the NPs.

We present an experimental and theoretical investigation of the spectroscopy of dilute alkali atoms in a solid matrix of inert gases at cryogenic temperatures, specifically Rubidium atoms in a solid Argon or Neon matrix, and related aspects of the interaction energies between the alkali atoms and the atoms of the solid matrix. The system considered is relevant for matrix isolation spectroscopy, and it is at the basis of a recently proposed detector of cosmological axions, exploiting magnetic-type transitions between Zeeman sublevels of alkali atoms in a magnetic field, tuned to the axion mass, assumed in the meV range. Axions are one of the supposed constituents of the dark matter (DM) of the Universe. This kind of spectroscopy could be also relevant for the experimental search of new physics beyond the Standard Model, in particular the search of violations of time-reversal or parity-charge-conjugation (CP) symmetry. In order to efficiently resolve the axion-induced transition in alkali-doped solid matrices, it is necessary to reduce as much as possible the spectral linewidth of the electronic transitions involved. The theoretical investigation presented in this paper aims to estimate the order of magnitude of the inhomogeneous contribution to the linewidth due to the alkali–matrix interactions (Coulomb/exchange and dispersion), and to compare the theoretical results with our experimental measurements of spectra of dilute Rubidium atoms in Argon and Neon solid matrix. The comparison of the expected or measured spectral linewidths will be important for selecting the most appropriate combination of alkali atoms and matrix inert elements to be used in the proposed axion detection scheme. It is finally suggested that dilute Lithium atoms diffused in a cold parahydrogen solid matrix could be, overall, a good system upon which the proposed detector could be based.

The use of traditional medicinal plants in Saudi Arabia stems mainly from consumers’ belief in prophetic medicine. This study was conducted to explore changes in patients’ use of dietary or herbal supplements among individuals infected with COVID-19 before and during infection and the association between herbal or dietary supplements and hospitalization. A cross-sectional, questionnaire-based study was conducted enrolling symptomatic patients who had recently recovered from COVID-19. Data were collected through phone interviews, and McNemar’s test was used to investigate changes to consumption of dietary or herbal supplements before and during infection. Multivariable logistic regression was used to investigate the association between supplements use during patients’ infection and hospitalization. A total of 738 patients were included in this study, of whom 32.1% required hospitalization. About 57% of participants were male with a mean age of 36.5 (±11.9) years. The use of lemon/orange, honey, ginger, vitamin C, and black seed among participants significantly increased during their infection. In contrast, patients using anise, peppermint, and coffee peel before their infection were more likely to stop using them during their infection. In addition, using lemon/orange (p < 0.0001), honey (p = 0.0002), ginger (p = 0.0053), vitamin C (p = 0.0006), black seed (p < 0.0001), peppermint (p = 0.0027), costus (p = 0.0095), and turmeric (p = 0.0012) was significantly higher among nonhospitalized patients than hospitalized ones. However, in the multivariable logistic regression, only use of vitamin C (OR = 0.51; 95% CI 0.33–0.79), peppermint (OR = 0.53; 95% CI 0.31–0.90), and lemon/orange (OR = 0.54; 95% CI 0.33–0.88) was associated with significantly lower odds of hospitalization. The study reveals that patients’ consumption of dietary or herbal supplements changed in response to their COVID-19 infection, with hospitalized patients having a lower likelihood of using these supplements. Because some supplements were associated with lower odds of hospitalization, these supplements or their bioactive components should be further investigated as feasible options for COVID-19 treatment.

BackgroundThe consumption of dietary supplements is highest among athletes and it can represent potential a health risk for consumers.ObjectiveThe aim of this study was to determine the prevalence of consumption of dietary supplements by road runners.MethodsWe interviewed 817 volunteers from four road races in the Brazilian running calendar. The sample consisted of 671 male and 146 female runners with a mean age of 37.9 ± 12.4 years.ResultsOf the sample, 28.33% reported having used some type of dietary supplement. The main motivation for this consumption is to increase in stamina and improve performance. The probability of consuming dietary supplements increased 4.67 times when the runners were guided by coaches. The consumption of supplements was strongly correlated (r = 0.97) with weekly running distance, and also highly correlated (r = 0.86) with the number of years the sport had been practiced. The longer the runner had practiced the sport, the higher the training volume and the greater the intake of supplements. The five most frequently cited reasons for consumption were: energy enhancement (29.5%), performance improvement (17.1%), increased level of endurance (10.3%), nutrient replacement (11.1%), and avoidance of fatigue (10.3%). About 30% of the consumers declared more than one reason for taking dietary supplements. The most consumed supplements were: carbohydrates (52.17%), vitamins (28.70%), and proteins (13.48%).ConclusionsSupplement consumption by road runners in Brazil appeared to be guided by the energy boosting properties of the supplement, the influence of coaches, and the experience of the user. The amount of supplement intake seemed to be lower among road runners than for athletes of other sports. We recommend that coaches and nutritionists emphasise that a balanced diet can meet the needs of physically active people.

Vitamin K is a group of lipophilic molecules. Forms of vitamin K play an essential role in the activation of specific proteins involved in blood clotting cascade or bone metabolism. Another molecule belonging to the fat-soluble vitamins group that also plays an important role in calcium metabolism is vitamin D3. The dietary supplements containing vitamins K and D3 are one of the most frequently consumed by patients. The objective of this work was to develop a simple, fast and sensitive thin-layer chromatography (TLC)-densitometric procedure for the simultaneous quantitative analysis of vitamins K and D3 in pharmaceutical products and dietary supplements. The analysis of vitamins was performed on the silica gel RP-18 F₂₅₄s plates with methanol-ethanol-isopropanol in a volume ratio of 15:1:4 as a mobile phase. The densitometric measurements were made at 254 nm. The method was validated by checking the specificity, linearity, precision, recovery, limit of detection, limit of quantification and robustness in accordance with International Conference on Harmonization (ICH) guidelines. The method was shown to be specific, accurate (recoveries were from 95.78 to 104.96%), linear over the tested range (correlation coefficient, exceeding 0.99), and precise (precision and intermediate precision RSD below 2.70% for all analytes). The satisfactory results of the validation of the method indicate that it can be used in the quality control of dietary supplements and pharmaceutical products containing vitamins K and D3.