[Determination of 18 caine anesthetics in animal meat using solid phase extraction combined with ultra-performance liquid chromatography-tandem mass spectrometry].

Because of the widespread application of anesthetic drugs in the fields of animal breeding and transportation, demand for the rapid, sensitive detection of anesthetic drugs in animal meat is increasing. The complex animal meat matrix contains various interfering substances, such as proteins, fats, and phospholipids, along with anesthetic drug residues at very low concentrations. Therefore, adopting appropriate pretreatment methods is necessary to improve the sensitivity of detection. In this study, a rapid, accurate analytical method based on ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) and solid phase extraction (SPE) was established to determine the contents of 18 caines in animal meat. The MS parameters, such as the collision energies of 18 caines, were optimized. Furthermore, the chromatographic separation conditions and response intensities of the caine in different mobile phases were compared. The effects of different pretreatment conditions on the extraction efficiencies of the 18 caines in meat samples and those of different purification conditions, such as extraction solvent, SPE column, and dimethylsulfoxide (DMSO) dosage, on their recoveries were investigated. Combined with the external standard method, the 18 caines in meat were successfully quantified. Sample pretreatment is a three-step process. First, in ultrasound-assisted extraction, 2.0 g samples were added to 2.0 mL water and extracted using 10 mL 0.1% (v/v) formic acid in acetonitrile under ultrasound conditions for 10 min. SPE was then performed using an Oasis PRIME HLB column. Finally, DMSO-assisted concentration was employed: the organic layer was collected and dried at 40 ℃ under a stream of N2 gas with the addition of 100 µL DMSO. Acetonitrile-water (1∶9, v/v) was added to the residue to yield a final volume of 1.0 mL for use in UPLC-MS/MS. The 18 caines were separated using an HSS T3 (100 mm×2.1 mm, 1.8 µm) column with 0.1% (v/v) formic acid in water (containing 0.02 mmol/L ammonium acetate) and methanol as mobile phases. Samples were detected using an electrospray ion source (ESI) in the positive ion and multiple reaction monitoring (MRM) modes during UPLC-MS/MS. Under the optimized conditions, the 18 target caine anesthetics displayed good linearities in the range of 1.00-50.0 µg/L, and the correlation coefficients (R2) were >0.999. The respective limits of detection (LODs) and quantification (LOQs) were 0.2-0.5 µg/kg, and 0.6-1.5 µg/kg. In pork, beef, and mutton samples, the recoveries obtained at three spiked levels were 83.4%-100.4% with relative standard deviations (RSDs) of 3.1%-8.5%. This simple, rapid, sensitive method may be applied in the detection of 18 caine anesthetics in animal meat and may provide technical support to the food safety department in China in monitoring the residues of caine anesthetics in animal meat.

Effect of cryoprotectant on the motility, viability, fertilization, and DNA integrity of naleh fish Barbonymus sp. (Cyprinidae) sperm / Efeito do crioprotetor na motilidade, viabilidade, fertilização e integridade do DNA no sêmen de peixes naleh Barbonymus sp. (Cyprinidae)

Naleh fish Barbonymus sp. is a commercial freshwater fish, which is indigenous to Aceh, Indonesia. The population of this species has declined over the years as a result of habitat perturbations and overfishing. Hence, the crucial need to develop a cryopreservation method to support breeding programs. This involved the use of a cryoprotectant as an important component. The objective of this study, therefore, was to explore the best cryoprotectant for naleh fish spermatozoa, and a total of five types were tested. These include the DMSO, Methanol, Ethanol, Glycerol, and Ethylene Glycol at a similar concentration of 10%, which were individually combined with 15% egg yolk, and every treatment was performed in three replications. Conversely, Ringer's solution was adopted as an extender, and the sperm was cryopreserved in liquid nitrogen for 15 days. The results showed significant influence on sperm motility and viability, as well as egg fertility of naleh fish (P <0.05), although the DMSO provided the best outcome, compared to others at 47.17%, 50.13%, and 45.67%, respectively. Furthermore, DNA fragmentation had not occurred in the fresh and cryopreserved sperm samples, indicating the protective effect of tested cryoprotectants. It is concluded that the 10% DMSO and 15% egg yolk is the best cryoprotectant for naleh fish spermatozoa.(AU)

O peixe naleh Barbonymus sp. é um peixe comercial de água doce, originário de Aceh, Indonésia. Durante vários anos, as perturbações provocadas no seu habitat e a pesca predatória determinaram o declínio da sua população, cuja preservação deve apoiar-se em um programa de reprodução controlada, com o emprego de espermatozoides criopreservados. O presente trabalho realizou um estudo comparativo de cinco crioprotetores: dimetilsultóxido, metanol, etanol, glicerol e etileno glicol. Todos os crioprotetores foram testados na concentração de 10%, combinados a 15% de gema de ovo. Cada tratamento foi efetuado em triplicatas. A solução de ringer foi utilizada como extensor e o esperma foi criopreservado em nitrogênio líquido por 15 dias. Os resultados obtidos revelaram a existência de influência significante (P<0,05) na viabilidade e motilidade espermática bem como na fertilidade dos ovos do peixe naleh, em que o dimetilsulfóxido apresentou o melhor resultado com os valores de 47,17%, 50,13% e 45,67%, respectivamente. Por outro lado, a fragmentação do DNA não ocorreu nas amostras de esperma fresco e criopreservado, indicando o efeito protetor dos crioprotetores testados. A conclusão obtida foi que o dimetilsulfóxido e 15% de gema de ovo foram o melhor crioprotetor para os espermatozoides do peixe naleh.(AU)

Real-time optical fiber sensors based on light diffusing microlens arrays.

The applications of optical fibers are impeded in implantable medical diagnostics due to incompatibility with biological tissues, and immune reaction in vivo. The utilization of biocompatible materials to construct a photonic sensing platform can reduce the immune response in in vivo medical diagnostics. Here, we developed real-time optical fiber sensors to determine the volumetric modulation of stimuli-responsive polymers. Asymmetric microlens structures were replicated on stimuli-sensitive hydrogels as stand-alone sensors and were chemically attached to the tips of silica and biocompatible optical fibers. Quantitative measurements were carried out using a smartphone to demonstrate the ease, simplicity, and practicality of the readout methodology. To demonstrate the utility in real-time sensing, the fiber probe was investigated in various concentrations of ethanol, propan-2-ol, and dimethyl sulfoxide. Also, the fiber probe showed a rapid response to pH in the acidic region with a sensitivity of 40 nW pH-1. To develop biocompatible probes for physiological applications, a microlens array-imprinted polymer was attached to the tip of a hydrogel optical fiber. The optical fiber probe in the refection configuration showed a sensitivity of 7 nW pH-1. The developed hydrogel fiber probes may have application in point-of-care diagnostics, continuous biomarker monitoring, and critical care sensing devices.

Marker-Independent In Situ Quantitative Assessment of Residual Cryoprotectants in Cardiac Tissues.

Cryomedium toxicity is a major safety concern when transplanting cryopreserved organs. Therefore, thorough removal of potentially toxic cryoprotective agents (CPAs) is required before transplantation. CPAs such as dimethyl-sulfoxide (DMSO), propylene glycol (PG), and formamide (FMD), routinely employed in ice-free cryopreservation (IFC), have advantages in long-term preservation of tissue structures compared with conventional cryopreservation employing lower CPA concentrations. This study evaluated the impact of potential residual CPAs on human cardiac valves. Raman microspectroscopy and Raman imaging were established as nondestructive marker-independent techniques for in situ quantitative assessment of CPA residues in IFC valve tissues. In detail, IFC valve leaflets and supernatants of the washing solutions were analyzed to determine the washing efficiency. A calibration model was developed according to the CPA's characteristic Raman signals to quantify DMSO, PG and FMD concentrations in the supernatants. Single point Raman measurements were performed on the intact tissues to analyze penetration properties. In addition, Raman imaging was utilized to visualize potential CPA residues. Our data showed that washing decreased the CPA concentration in the final washing solution by 99%, and no residues could be detected in the washed tissues, validating the multistep CPA removal protocol routinely used for IFC valves. Raman analysis of unwashed tissues showed different permeation characteristics depending on each CPA and their concentration. Our results demonstrate a great potential of Raman microspectroscopy and Raman imaging as marker-independent in situ tissue quality control tools with the ability to assess the presence and concentration of different chemical agents or drugs in preimplantation tissues.

Screening a trace amount of pharmaceutical cocrystals by using an enhanced nano-spot method.

Cocrystallization is an attractive and promising technology that can improve the physical properties of formulations of active pharmaceutical ingredients (APIs). We have developed a "nano-spot method" that can evaluate the crystalline form on the nanogram scale. In this study, the following studies were performed to obtain versatile and comprehensive improvements to the nano-spot method: modification of the sample solution, application of solvent vapor exposure to attempt the precipitation of various states of crystals, and adoption of low-frequency Raman spectroscopy. Carbamazepine was used as a model API and cocrystallization screening was examined with 12 cocrystal formers (coformers). In the case of combinations that are already known to form cocrystals, spectra similar to those of previously reported cocrystals or new spectra were obtained. It was considered that the reported cocrystals or new polymorphs were obtained. In contrast, in the case of the combination which has been reported not to form a cocrystal, the spectra were consistent with that for the physical mixture of API and coformer, suggesting that a cocrystal also did not form in this screening. In addition, the newly adopted low-frequency Raman spectroscopy enabled the high-sensitive detection of the crystalline form.

Comparison of solvate ionic liquids and DMSO as an in vivo delivery and storage media for small molecular therapeutics.

BACKGROUND: Solvate ionic liquids (SILs) are a new class of ionic liquids that are equimolar solutions of lithium bistrifluoromethanesulfonimide in either triglyme or tetraglyme, referred to as G3LiTFSA and G4LiTFSA, respectively. SILs play a role in energy storage lithium batteries, and have been proposed as potential alternatives to traditional organic solvents such as DMSO. G3TFSA and G4TFSA have been shown to exhibit no toxicity in vivo up to 0.5% (v/v), and solubilize small compounds (N,N-diethylaminobenzaldehyde) with full penetrance, similar to DMSO delivered DEAB. Herein, we compare the effects of storage (either at room temperature or - 20 °C) on DEAB solubilized in either DMSO, G3TFSA or G4TFSA to investigate compound degradation and efficacy. RESULTS: The findings show that DEAB stored at room temperature (RT) for 4 months solubilized in either G3TFSA, G4TFSA or DMSO displayed no loss of penetrance. The same was observed with stock solutions stored at - 20 °C for 4 months; however G4TFSA remained in a liquid state compared to both G3TFSA and DMSO. Moreover, we examined the ability of G3TFSA and G4TFSA to solubilize another small molecular therapeutic, the FGFR antagonist SU5402. G4TFSA, unlike G3TFSA solubilized SU5402 and displayed similar phenotypic characteristics and reduced dlx2a expression as reported and shown with SU5402 in DMSO; albeit more penetrative. CONCLUSION: This study validates the use of these ionic liquids as a potential replacement for DMSO in vivo as organic solubilizing agents.

Annual cycle of dimethylsulfoniopropionate (DMSP) and dimethylsulfoxide (DMSO) related to phytoplankton succession in the Southern North Sea.

The influence of abiotic and biotic variables on the concentration of dimethyl sulfide (DMS), dimethylsulfoniopropionate (DMSP), and dimethylsulfoxide (DMSO), were investigated during an annual cycle in 2016 in the Belgian Coastal Zone (BCZ, North Sea). We reported strong seasonal variations in the concentration of these compounds linked to the phytoplankton succession with high DMS(P,O) producers (mainly Phaeocystis globosa) occurring in spring and low DMS(P,O) producers (various diatoms species) occurring in early spring and autumn. Spatial gradients of DMS and DMSP were related to those of phytoplankton biomass itself related to the inputs of nutrients from the Scheldt estuary. However, the use of a relationship with Chlorophyll-a (Chl-a) concentration is not sufficient to predict DMSP. Accounting for the phytoplankton composition, two different DMSP versus Chl-a correlations could be established, one for diatoms and another one for Phaeocystis colonies. We also reported high nearshore DMSO concentrations uncoupled to Chl-a and DMSP concentrations but linked to high suspended particulate matter (SPM) presumably coming from the Scheldt estuary as indicated by the positive relationship between annual average SPM and salinity.

The Application of Quantitative ¹H-NMR for the Determination of Orlistat in Tablets.

A quantitative nuclear magnetic resonance (qNMR) method to measure the content of Orlistat in tablets was studied and found to be efficient, accurate, reliable, and simple. In this paper, phloroglucinolanhydrous and dimethylsulfoxide-d6 (DMSO-d6) served as the internal standard and solvent, respectively. The qNMR methodology, including the linearity, range, the limit of detection (LOD) and quantification (LOQ), stability, precision, and accuracy, was validated seriatim, and the results were very favorable. The content determination results of three batches of Orlistat in tablets were almost identical upon comparing the qNMR method and the high-performance liquid chromatography (HPLC) method. The recommended method authentically compensated the deficiencies of the current HPLC method for determining Orlistat content, and proved to be a method complementary to traditional analysis for the purity measurement of Orlistat in some pharmaceutical preparations.

A long-lived ferrocene-conjugated iridium(III) complex for sensitive turn-on luminescence detection of traces of DMSO in water and human serum.

The development of an efficient sensor for the determination of the DMSO content in aqueous solution is highly desirable in a number of chemical industries. Presented herein is a ferrocene-conjugated iridium(III) complex, which exhibits remarkable capability to detect traces of DMSO (<1% v/v) in aqueous solution through a turn-on luminescence sensing mechanism. The extraordinary sensitivity and selectivity of this newly developed complex for DMSO renders it as one of the most powerful DMSO sensors known.

Photochemical oxidation of dimethylsulphide to dimethylsulphoxide in estuarine and coastal waters.

Dimethylsulphide (DMS) photo-oxidation and dimethylsulphoxide (DMSO) photoproduction were estimated in 26 laboratory irradiations of coastal samples from NE England (Tyne estuary) and W Scotland (Loch Linnhe and River Nant at Taynuilt). Pseudo-first order rate constants of DMS photo-oxidation (0.038 h-1 to 0.345 h-1) and DMSO photo-production (0.017 h-1 to 0.283 h-1) varied by one order of magnitude and were lowest in the coastal North Sea. Estuarine samples (salinity S < 30) had a mean DMSO yield of 96 ± 16% (n = 14), consistent with 1:1 M conversion via photosensitised oxidation by singlet oxygen. Photochemical rate constants were strongly correlated with coloured dissolved organic matter (CDOM) absorption coefficients at 350 nm, a350. Variations in a350 explained 61% (R2 = 0.61, n = 26) and 73% (R2 = 0.73, n = 17) of the variability in DMS photo-oxidation and DMSO production, respectively. However, CDOM normalised photochemical rate constants increased strongly towards coastal waters exhibiting lowest CDOM absorbance, indicating water samples of marine character (S > 30) to be most reactive with respect to DMS photo-oxidation. Estimates of water column averaged DMS photo-oxidation rate constants, obtained by scaling to mean daily irradiance (July, NE England) and mid-UV underwater irradiance, were 0.012 d-1, 0.019 d-1, and 0.017 d-1 for upper estuary (S < 20), lower estuary (20 < S < 30) and coastal waters (S > 30), at the lower end of previous observations. Comparing our water column averaged DMS photo-oxidation rate constants with estimated DMS losses via air-sea gas exchange and previously reported biological consumption implies that DMS photochemical removal is of only minor importance in our study area.

Preservation of Domesticated Honey Bee (Hymenoptera: Apidae) Drone Semen.

Preservation of honey bee (Apis mellifera L., Hymenoptera: Apidae) sperm, coupled with instrumental insemination, is an effective strategy to protect the species and their genetic diversity. Our overall objective is to develop a method of drone semen preservation; therefore, two experiments were conducted. Hypothesis 1 was that cryopreservation (-196 °C) of drone semen is more effective for long-term storage than at 16 °C. Our results show that after 1 yr of storage, frozen sperm viability was higher than at 16 °C, showing that cryopreservation is necessary to conserve semen. However, the cryoprotectant used for drone sperm freezing, dimethyl sulfoxide (DMSO), can harm the queen and reduce fertility after instrumental insemination. Hypothesis 2 was that centrifugation of cryopreserved semen to reduce DMSO prior to insemination optimize sperm quality. Our results indicate that centrifuging cryopreserved sperm to remove cryoprotectant does not affect queen survival, spermathecal sperm count, or sperm viability. Although these data do not indicate that centrifugation of frozen-thawed sperm improves queen health and fertility after instrumental insemination, we demonstrate that cryopreservation is achievable, and it is better for long-term sperm storage than above-freezing temperatures for duration of close to a year.

Determination of residual dimethylsulfoxide in cryopreserved cardiovascular allografts.

Dimethylsulfoxide (DMSO) is a solvent which protects the structure of allografts during the cryopreservation and thawing process. However, several toxic effects of DMSO in patients after transplantation of cryopreserved allografts have been described. The aim of this study is to determine the residual DMSO in the cardiovascular allografts after thawing and preparation of cryopreserved allografts for clinical application following guidelines of the European Pharmacopoeia for DMSO detection. Four types of EHB allografts (aortic valve-AV, pulmonary valve-PV, descending thoracic aorta-DA, and femoral artery-FA) are cryopreserved using as cryoprotecting solution a 10% of DMSO in medium 199. Sampling is carried out after thawing, after DMSO dilution and after delay of 30 min from final dilution (estimated delay until allograft implantation). After progressive thawing in sterile water bath at 37-42 °C (duration of about 20 min), DMSO dilution is carried out by adding consecutively 33, 66 and 200 mL of saline. Finally, tissues are transferred into 200 mL of a new physiologic solution. Allograft samples are analysed for determination of the residual DSMO concentration using a validated Gas Chromatography analysis. Femoral arteries showed the most important DMSO reduction after the estimated delay: 92.97% of decrease in the cryoprotectant final amount while a final reduction of 72.30, 72.04 and 76.29% in DMSO content for AV, PV and DA, was found, respectively. The residual DMSO in the allografts at the moment of implantation represents a final dose of 1.95, 1.06, 1.74 and 0.26 mg kg-1 in AV, PV, DA and FA, respectively, for men, and 2.43, 1.33, 2.17 and 0.33 mg kg-1 for same tissues for women (average weight of 75 kg in men, and 60 kg in women). These results are seriously below the maximum recommended dose of 1 g DMSO kg-1 (Regan et al. in Transfusion 50:2670-2675, 2010) of weight of the patient guaranteeing the safety and quality of allografts.

Multimodal Broadband Vibrational Sum Frequency Generation (MM-BB-V-SFG) Spectrometer and Microscope.

A broadband sum frequency generation (BB-SFG) spectrometer with multimodal (MM) capabilities was constructed, which could be routinely reconfigured for tabletop experiments in reflection, transmission, and total internal reflection (TIR) geometries, as well as microscopic imaging. The system was constructed using a Ti:sapphire amplifier (800 nm, pulse width = 85 fs, repetition rate = 2 kHz), an optical parameter amplification (OPA) system for production of broadband IR pulses tunable between 1000 and 4000 cm(-1), and two Fabry-Pérot etalons arranged in series for production of narrowband 800 nm pulses. The key feature allowing the MM operation was the nearly collinear alignment of the visible (fixed, 800 nm) and infrared (tunable, 1000-4000 cm(-1)) pulses which were spatially separated. Physical insights discussed in this paper include the comparison of spectral bandwidth produced with 40 and 85 fs pump beams, the improvement of spectral resolution using etalons, the SFG probe volume in bulk analysis, the normalization of SFG signals, the stitching of multiple spectral segments, and the operation in different modes for air/liquid and adsorbate/solid interfaces, bulk samples, as well as spectral imaging combined with principle component analysis (PCA). The SFG spectral features obtained with the MM-BB-SFG system were compared with those obtained with picosecond-scanning-SFG system and high-resolution BB-SFG system (HR-BB-SFG) for dimethyl sulfoxide, α-pinene, and various samples containing cellulose (purified commercial products, Cladophora cell wall, cotton and flax fibers, and onion epidermis cell wall).

Highly selective colorimetric and fluorometric chemosensor for cyanide on silica gel and DMSO/H2O (7:3 v/v) mixed solvent and its imaging in living cells.

The chemosensor 2,3-bis((E)-((2-hydroxynaphthalen-1-yl)methylene)amino)maleonitrile (1) has been synthesized using 2-hydroxy-1-napthaldehyde and 2,3-diaminomaleonitrile and characterized. Sensor 1 exhibits selective binding with CN(-) in dimethyl sulfoxide (DMSO)/H2O (7:3 v/v) and DMSO/aqueous Tris (Tris(hydroxymethyl)aminomethane) buffer (7:3 v/v, 10 mM, pH 7.2) media with significant changes in its UV-visible and fluorescence spectra. Titration of 1-Zn(II) complex with CN(-) ion in DMSO/aqueous Tris buffer (7:3 v/v, 10 mM, pH 7.2) regenerates the free sensor 1, as supported by UV-visible spectra. (1)H NMR titration of 1 with CN(‒) in (CD3)2SO confirms the hydrogen-bonding interaction between the two OH groups of the former and the latter in bidentate manner. Sensor 1 impregnated on silica gel thin layer chromatography (TLC) strip followed by dipping in anion solutions in DMSO/H2O (7:3 v/v) generates yellow to red spectacular colour change with CN(-) ion selectively which can be exploited as potential tool for ready-made detection of toxic CN(-) ion in environmental and analytical chemistry. Similar visual change in colour for 1 is observed selectively with CN(-) also when both of them are taken in DMSO/H2O (7:3 v/v) solution. Sensor 1 is used as an imaging reagent for detection of the cellular uptake of CN(-) ion in Baby Hamster Kidney (BHK-21) cells.

Factors affecting degradation of dimethyl sulfoxide (DMSO) by fluidized-bed Fenton process.

In this study, the target compound is dimethyl sulfoxide (DMSO), which is used as a photoresist stripping solvent in the semiconductor and thin-film transistor liquid crystal display (TFT-LCD) manufacturing processes. The effects of the operating parameters (pH, Fe(2+) and H2O2 concentrations) on the degradation of DMSO in the fluidized-bed Fenton process were examined. This study used the Box-Behnken design (BBD) to investigate the optimum conditions of DMSO degradation. The highest DMSO removal was 98 % for pH 3, when the H2O2 to Fe(2+) molar ratio was 12. At pH 2 and 4, the highest DMSO removal was 82 %, when the H2O2 to Fe(2+) molar ratio was 6.5. The correlation of DMSO removal showed that the effect of the parameters on DMSO removal followed the order Fe(2+) > H2O2 > pH. From the BBD prediction, the optimum conditions were pH 3, 5 mM of Fe(2+), and 60 mM of H2O2. The difference between the experimental value (98 %) and the predicted value (96 %) was not significant. The removal efficiencies of DMSO, chemical oxygen demand (COD), total organic carbon (TOC), and iron in the fluidized-bed Fenton process were higher than those in the traditional Fenton process.

Kinetics and mechanistic investigation into the possible activation of imidazolium trans-[tetrachloridodimethylsulfoxideimidazoleruthenate(III)], NAMI-A, by 2-mercaptoethane sulfonate.

Imidazolium trans-[tetrachloridodimethylsulfoxideimidazoleruthenate(III)], NAMI-A, is a promising antimetastatic prodrug with high specificity for metastatic cancer cells. Limited activity of NAMI-A against primary tumor suggests that its use in combination with other anticancer drug(s) might present a more desirable therapeutic outcome. The mechanism of activation and action of this prodrug is still largely unknown. The biological targets, as well, have not yet been delineated. The kinetics and mechanism of interaction of NAMI-A with 2-mercaptoethane sulfonate, MESNA, a chemoprotectant, have been studied spectrophotometrically under pseudo-first order conditions of excess MESNA. The reaction is characterized by initial reduction of NAMI-A and formation of dimeric MESNA as evidenced by electospray ionization mass spectrometry. A first order dependence on both NAMI-A and MESNA was obtained and a bimolecular rate constant of 0.71 ± 0.06 M(-1) s(-1) was deduced. Activation parameters determined (ΔS(≠) = -178.12 ± 0.28 J K(-1) mol(-1), ΔH(≠) = 20.64 ± 0.082 kJ mol(-1) and ΔG(≠) = 75.89 ± 1.76 kJ mol(-1) at 37 ± 0.1 °C and pH 7.4) are indicative of formation of an associative intermediate prior to product formation and subsequent hydrolysis of the reduced complex. Our results suggest that MESNA might be able to activate the prodrug while still protecting against toxicity when given in a regimen involving NAMI-A and chemotherapy drug(s) that induce bladder and kidney toxicities.

Effects of diet-matrix on volatile organic compounds in breath in diet-induced obese mice.

Breath gas analysis in humans proved successful in identifying disease states and assessing metabolic functions in a non-invasive way. While many studies report diagnostic capability using volatile organic compounds (VOC) in breath, the inter-individual variability even in healthy human cohorts is rather large and not completely understood in its biochemical origin. Laboratory mice are the predominant animal model system for human disorders and are analysed under highly standardized and controlled conditions. We established a novel setup to monitor VOCs as biomarkers for disease in the breath gas of non-anesthetized, non-restrained mice using a proton transfer reaction mass spectrometer with time of flight detection. In this study, we implemented breath gas analysis in a dietary intervention study in C57BL/6J mice with the aim to assess the variability in VOC signatures due to a change in the diet matrix. Mice were fed a standard laboratory chow and then exposed to four semi-purified low- or high-fat diets for four weeks. Random forest (RF++) was used to identify VOCs that specifically respond to the diet matrix change. Interestingly, we found that the change from a chow diet to semi-purified diets resulted in a considerable drop of several VOC levels. Our results suggest that the diet matrix impacts VOC signatures and the underlying metabolic functions and may be one source of variability in exhaled volatiles.

Overcoming matrix effects: GC method development for the determination of triethylamine and dimethyl sulfoxide in a drug substance.

A direct injection gas chromatography method was developed for the determination of triethylamine and dimethyl sulfoxide (DMSO) in a drug substance (ML-189). Matrix effects were found to result in the overestimation of DMSO when methanol was used as diluent. Multiple approaches to eliminate matrix effects were unsuccessful; these included changes in sample size, split ratio, injector temperature and injector liner (e.g., deactivated liner). Ultimately, matrix effects were eliminated after the diluent was changed from methanol to acetone. A mechanism was proposed and discussed.

Photoproduced fluorescent Au(I)@(Ag2/Ag3)-thiolate giant cluster: an intriguing sensing platform for DMSO and Pb(II).

Synergistic evolution of fluorescent Au(I)@(Ag2/Ag3)-thiolate core-shell particles has been made possible under the Sun in presence of the respective precursor coinage metal compounds and glutathione (GSH). The green chemically synthesized fluorescent clusters are giant (∼600 nm) in size and robust. Among all the common water miscible solvents, exclusively DMSO exhibits selective fluorescence quenching (Turn Off) because of the removal of GSH from the giant cluster. Again, only Pb(II) ion brings back the lost fluorescence (Turn On) leaving aside all other metal ions. This happens owing to the strong affinity of the sulfur donor of DMSO for Pb(II). Thus, employing the aqueous solution containing the giant cluster, we can detect DMSO contamination in water bodies at trace level. Besides, a selective sensing platform has emerged out for Pb(II) ion with a detection limit of 14 × 10(-8) M. Pb(II) induced fluorescence recovery is again vanished by I(-) implying a promising route to sense I(-) ion.