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The detection and quantification of additives in tobacco products are critical for ensuring consumer safety and compliance with regulatory standards. Traditional analytical techniques, like gas chromatography–mass spectrometry (GC–MS), liquid chromatography–mass spectrometry (LC–MS), and others, although effective, suffer from drawbacks, including complex sample preparation, high costs, lengthy analysis times, and the requirement for skilled operators. This study addresses these challenges by evaluating the efficacy of mid-infrared (MIR) spectroscopy and near-IR (NIR) spectroscopy, coupled with multivariate analysis, as potential solutions for the detection and quantification of additives in tobacco products. So, a representative set of tobacco products was selected and spiked with the targeted additives, namely caffeine, menthol, glycerol, and cocoa. Multivariate analysis of MIR and NIR spectra consisted of principal component analysis (PCA), hierarchical clustering analysis (HCA), partial least squares-discriminant analysis (PLS-DA) and soft independent modeling of class analogy (SIMCA) to classify samples based on targeted additives. Based on the unsupervised techniques (PCA and HCA), a distinction could be made between spiked and non-spiked samples for all four targeted additives based on both MIR and NIR spectral data. During supervised analysis, SIMCA achieved 87–100% classification accuracy for the different additives and for both spectroscopic techniques. PLS-DA models showed classification rates of 80% to 100%, also demonstrating robust performance. Regression studies, using PLS, showed that it is possible to effectively estimate the concentration levels of the targeted molecules. The results also highlight the necessity of optimizing data pretreatment for accurate quantification of the target additives. Overall, NIR spectroscopy combined with SIMCA provided the most accurate and robust classification models for all target molecules, indicating that it is the most effective single technique for this type of analysis. MIR, on the other hand, showed the overall best performance for quantitative estimation.

Although the addition of buffers provides improved stability to flucloxacillin (FLU) solutions, unbuffered solutions are often preferred in clinical practice. The first purpose of this study was to investigate whether a 50 mg/mL solution of FLU in normal saline is stable for 24 h at 33 °C so that it can be applied for outpatient parenteral antimicrobial therapy (OPAT) using portable elastomeric infusion pumps (PEIPs). When the PEIPs were stored in an oven at 33 °C and deflated over 24 h, the volume of the collected solution, pH, and FLU concentration were checked every 4 h. Obtaining better results than expected based on the literature data, other storage conditions, such as refrigeration, room temperature (RT), 37 °C, refrigeration followed by 24 h at 33 °C and 37 °C, and different batches/brands, were also tested. This study confirmed the pronounced effect of temperature on the stability of FLU and also showed the relationship between the stability of FLU and the initial pH of the solution. FLU was quite stable at refrigeration and RT conditions, with more than 99% and 95% remaining. After 24 h at 33 °C, more than 92% of FLU was still present in the solution, while this number decreased to less than 85% when the storage temperature reached 37 °C. The remaining percentage was found to be even lower when the solution was stored at 2–8 °C for 6 days, followed by 24 h storage at 33 °C or 37 °C, with losses of 17% and 30%, respectively. The stability of FLU became worse when the initial pH of the solution was lower than 5.9 since the concentration of FLU dropped to less than 90% after 24 h at 33 °C, and a precipitate started to form when the initial pH of the solution was around 5.3. Therefore, FLU in PEIPs could be employed for 24 h if the temperature was ideally not more than 33 °C, while the pH should be not less than 5.9 upon reconstituting the FLU solution.

In this study, a liquid chromatographic method was developed for the fast determination of lincomycin, polymyxin and vancomycin in a preservation solution for transplants. A Kinetex EVO C18 (150 × 4.6 mm, 2.6 µm) column was utilized at 45 °C. Gradient elution was applied using a mixture of mobile phases A and B, both including 30 mM phosphate buffer at pH 2.0 and acetonitrile, at a ratio of 95:5 (v/v) for A and 50:50 (v/v) for B. A flow rate of 1.0 mL/min, an injection volume of 20 µL and UV detection at 210 nm were used. A degradation study treating the three antibiotics with 0.5 M hydrochloric acid, 0.5 M sodium hydroxide and 3% H2O2 indicated that the developed method was selective toward lincomycin, polymyxin, vancomycin and their degradation products. Other ingredients of the preservation solution, like those from the cell culture medium, did not interfere. The method was validated with good sensitivity, linearity, precision and accuracy. Furthermore, lincomycin, polymyxin and vancomycin were found to be stable in this preservation solution for 4 weeks when stored at −20 °C.

Vaping electronic cigarettes (e-cigarettes) has become a popular alternative to smoking tobacco. When an e-cigarette is activated, a liquid is vaporized by heating, producing an aerosol that users inhale. While e-cigarettes are marketed as less harmful than traditional cigarettes, there are ongoing concerns about their long-term health effects, including potential lung damage. Therefore, it is essential to closely monitor and study the composition of e-liquids. E-liquids typically consist of propylene glycol, glycerin, flavorings and nicotine, though there have been reports of non-compliant nicotine concentrations and the presence of illegal additives. This study explored spectroscopic techniques to examine the conformity of nicotine labeling and detect the presence of the not-allowed additives: the caffeine, taurine, vitamin E and cannabidiol (CBD) in e-liquids. A total of 236 e-liquid samples were carefully selected for analysis. Chemometric analysis was applied to the collected data, which included mid-infrared (MIR) and near-infrared (NIR) spectra. Supervised modeling approaches such as partial least squares-discriminant analysis (PLS-DA) and soft independent modeling of class analogy (SIMCA) were employed to classify the samples, based on the presence of nicotine and the targeted additives. This study demonstrates the efficacy of MIR and NIR spectroscopic techniques in conjunction with chemometric methods (SIMCA and PLS-DA) for detecting specific molecules in e-liquids. MIR with autoscaling data preprocessing and PLS-DA achieved 100% classification rates for CBD and vitamin E, while NIR with the same approach achieved 100% for CBD and taurine. Overall, MIR combined with PLS-DA yielded the best classification across all targeted molecules, suggesting its preference as a singular technique.

Abstract Metronidazole in aqueous solution is sensitive to light and UV irradiation, leading to the formation of N-(2-hydroxyethyl)-5-methyl-l,2,4-oxadiazole-3-carboxamide. This is revealed here by liquid chromatography with tandem photo diode array detection and mass spectrometry (LC-PDA-MS) and further verified by comparison with the corresponding reference substance and proton nuclear magnetic resonance (1H-NMR). However, in current compendial tests for related substances/organic impurities of metronidazole, the above photolytic degradant could not be detected. Thus, when photodegradation of metronidazole occurs, it could not be demonstrated. In our study, an improved LC method was developed and validated, which includes a detection at a wavelength of 230 nm and optimization of mobile phase composition thereby a better separation was obtained.

The popularity of plant food supplements has seen explosive growth all over the world, making them susceptible to adulteration and fraud. This necessitates a screening approach for the detection of regulated plants in plant food supplements, which are usually composed of complex plant mixtures, thus making the approach not so straightforward. This paper aims to tackle this problem by developing a multidimensional chromatographic fingerprinting method aided by chemometrics. To render more specificity to the chromatogram, a multidimensional fingerprint (absorbance × wavelength × retention time) was considered. This was achieved by selecting several wavelengths through a correlation analysis. The data were recorded using ultra-high-performance liquid chromatography (UHPLC) coupled with diode array detection (DAD). Chemometric modelling was performed by partial least squares–discriminant analysis (PLS-DA) through (a) binary modelling and (b) multiclass modelling. The correct classification rates (ccr%) by cross-validation, modelling, and external test set validation were satisfactory for both approaches, but upon further comparison, binary models were preferred. As a proof of concept, the models were applied to twelve samples for the detection of four regulated plants. Overall, it was revealed that the combination of multidimensional fingerprinting data with chemometrics was feasible for the identification of regulated plants in complex botanical matrices.

A new, simple and sensitive ion chromatography (IC) method for the determination of sodium, potassium, magnesium, calcium and chloride in a parenteral nutrition (PN) solution was developed and validated. Before sample analysis, a sample pretreatment by calcination was applied which could totally remove interference from other constituents of the PN solution. Methanesulfonic acid (MSA) and sodium hydroxide were used as the mobile phase for the determination of cations and anions, respectively. The calibration curves showed good correlation between analyte peak area and concentration (r2 > 0.999). Detection limits ranged from 0.0001 to 0.02 mg/L and quantification limits from 0.0002 to 0.06 mg/L. Relative standard deviation (RSD) values for repeatability and inter-day precision did not exceed 1.0% and the recoveries for all analytes were between 99.1–101.1%. The robustness was verified by using an experimental design.

Tobramycin is one of the aminoglycoside antibiotics that lack a UV absorbing chromophore. However, the application of pulsed electrochemical detection (PED) has been used successfully for the analysis of this and similar antibiotics. This work describes an improved liquid chromatographic (LC) method combined with PED, which is able to separate much more impurities than before. Using a Discovery C-18 RP column (250mmÃ4.6mm i.d., 5μm), isocratic elution was carried out with a mobile phase, containing sodium sulfate (35g/L), sodium octanesulphonic acid (1g/L), tetrahydrofuran (14mL/L) and 0.2M phosphate buffer pH 3.0 (50mL/L). Using these experimental conditions, the limit of quantification (LOQ, S/N=10) was 5ng. The linearity was examined in the range LOQ-60μg/mL and the coefficient of determination was 0.998. The method also proved to be repeatable and the recovery was close to 100%. The influence of the different chromatographic parameters on the separation was investigated by means of an experimental design. The proposed method is useful in quality control of tobramycin drug substances and drug products. Keywords: Liquid chromatography-Pulsed electrochemical detection, Tobramycin, Aminoglycoside antibiotics

One important aspect that determines the quality of human life is sexual life. Therefore, sexual activity to be one part in the assessment of the quality of human life. In everyday life, not infrequently encountered sexual problem in various communities, an estimated 322 million people both men and women experience sexual dysfunction worldwide. One of the factors that cause sexual dysfunction that is very important is lifestyle. Lifestyle that includes physical activity would interfere with organ function so that the body is not healthy and does not fit include decreased sexual fitness. Many studies have reported that the results of unhealthy lifestyle, especially diet and sleep patterns, can interfere with a person's sexual ability. In addition to lifestyle, excessive physical activity also decreases sexual function. But in contrast, a good control on lifestyle and physical activity will enhance the ability of sexual activity.