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Signal enhancement in laser diode thermal desorption-triple quadrupole mass spectrometry analysis using microwell surface coatings
摘要： Laser diode thermal desorption (LDTD) is an ionization source usually coupled to triple quadrupole mass spectrometry (QqQMS) and specifically designed for laboratories requiring high-throughput analysis. It has been observed that surface coatings on LDTD microwell plates can improve the sensitivity of the analysis of small polar molecules. The objective of the present study is to understand and quantify the effect of microwell surface coatings on signal intensity of small organic molecules of clinical, environmental and forensic interest. Experiments showed that the peak areas of diclofenac, chloramphenicol, salicylic acid and 11-nor-9-carboxy-Δ9-tetrahydrocannabinol obtained by LDTD-QqQMS increased by up to 3 orders of magnitude when using microwells coated with ethylenediaminetetraacetic acid (EDTA). Tests with different chelating agents and polytetrafluoroethylene as microwell surface coatings showed that nitrilotriacetic acid gave significantly higher peak areas for five out of the nine compounds that showed signal enhancement using chelating agents as coatings. Scanning electron microscopy studies of EDTA-coated and uncoated microwells showed that analytes deposited in the former formed more uniform and thinner films than in the latter. The enhancement effect of surface coatings in LDTD-QqQMS was explained mainly by the formation of homogenous and thinner layers of nanocrystals of analytes that are easier to desorb thermally than the layers formed when the analytes dry in direct contact with the bare stainless steel surface. Chemisorption of some analytes to the stainless steel surface of the microwell plate appeared to be a minor factor. Surface coatings widen the number of compounds analyzable by LDTD-QqQMS and can also improve sensitivity and limits of detection.
关键词： pharmaceuticals,high-throughput,hormones,pesticides,x-ray photoelectron spectroscopy,scanning electron microscopy,stainless steel,small organic molecules,chelating agents
更新于2025-09-23 15:23:52
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Selective Laser Sintering 3D Printing a?? An Overview of the Technology and Pharmaceutical Applications
摘要： Food and Drug Administration (FDA) has approved a drug product (Spritam?) and many medical devices manufactured by 3-dimensional printing (3DP) processes for human use. There is immense potential to print personalized medicines using 3DP. Many 3DP methods have been reported in the literature for pharmaceutical applications. However, selective laser sintering (SLS) printing has remained least explored for pharmaceutical applications. There are many advantages and challenges in adopting a SLS method for fabrication of personalized medicines. Solvent free nature, availability of FDA approved thermoplastic polymer/excipients (currently used in hot melt-extrusion process), minimal/no post-processing step, etc. are some of the advantages of the SLS printing process. Major challenges of the technology are requirement of at least one thermoplastic component in the formulation and thermal stability of drug and excipients. This review provides an overview of the SLS printing method, excipient requirements, process monitoring, quality defects, regulatory aspects and potential pharmaceutical applications.
关键词： in-process monitoring,selective laser sintering,personalized medication,3D printing,quality defects,pharmaceuticals
更新于2025-09-23 15:21:01
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Microwave discharge electrodeless mercury lamp (Hg-MDEL): an energetic, mechanistic and kinetic approach to the degradation of Prozac?
摘要： A photochemical reactor composed of an Hg-MDEL was applied in photodegradation studies of fluoxetine (Prozac?). The reactor exhibited to be an efficient hydroxyl radical generation system, since constant of formation of OH? formation is optimized through the adjustment of this parameter. An increase in the initial hydroxycoumarin (4HC) and 7-hydroxycoumarin (7HC) solutions resulted in the kinetics constant value, the mean kinetic constant was k = 10.64 ± 1.25 min -1 and R 2 = 0.943 ± 0.131. The Prozac? photodegradation studies showed that the application of the pseudo-first-order applied for degradation of Prozac?, the study of variation of the microwave power allowed a concentration of Prozac from 33 to 134 μmol L-1 resulted in a 21% decrease in the kinetic significant increase in the rate of degradation of the Prozac?, indicating that the hydroxyl radical the OH? quantification studies conducted with coumarin (COU), 4- kOH = 3.14 ± 0.18 min-1. When the Hg-MDEL reactor was 100% for its highest concentration (134 μmol L-1) at the time of 0.75 min. As for the solution of Prozac? 101 μmol L-1, the energy consumption was 6 kWh g-1, achieving a removal of 99%. formation of hydroxyl radicals, a high degradation rate of organic compounds (Prozac?, COU influence exerted by the transformation products. In general, the total removal of Prozac? was kinetics should be limited to the time of up to 0.50 min for the respective system, due to the Finally, the photochemical system presented in this work demonstrates a high efficiency in the and 7HC) and low energy consumption.
关键词： hydroxyl radical,direct photolysis,fluoxetine,pharmaceuticals,and kinetics,degradation mechanism
更新于2025-09-19 17:15:36
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Visible-light-driven Photocatalytic Removal of PPCPs using Magnetically Separable Bismuth Oxybromo-iodide Solid Solutions: Mechanisms, Pathways, and Reusability in Real Sewage
摘要： In testing a series of bismuth oxybromo-iodide (BiOBrxI1-x; 0 ≤ x ≤ 1) solid solutions, BiOBr0.9I0.1, due to its superior charge-carriers separation, exhibited the best performance in the visible-light-driven photocatalytic degradation of pharmaceutical and personal care products (PPCPs). Subsequently, its superparamagnetic version, BiOBr0.9I0.1/Fe3O4@SiO2, possessing a mesoporous hierarchical morphology, was solvothermally developed, and completely degraded the two model PPCPs, ibuprofen and benzophenone-3, in 1 and 2 h, respectively. Scavenger studies revealed that the ibuprofen degradation was dominated by e–, ?O2–, and h+, while the benzophenone-3 degradation was dominated by e– and ?O2–. Hydroxylation, decarboxylation, and demethylation were found to be the major reactions involved in the degradation pathways. The aquatic toxicity of the intermediates ― estimated using the ECOSAR software ― was found to be lower than for the parent PPCP molecules, indicating a reduced environmental risk after photocatalytic degradation. The solution matrix study elaborated the varying extent of the interacting roles of the co-present anions, cations, and NOM. The reusability and stability of BiOBr0.9I0.1/Fe3O4@SiO2 was examined in real secondary treated sewage in a prototype photocatalytic reactor equipped with a magnetic separator. Due to the interferences and unwanted interactions caused by the co-present constituents in secondary treated sewage, a gradual loss in the photocatalytic performance of BiOBr0.9I0.1/Fe3O4@SiO2 was observed during consecutive rounds of recycling.
关键词： visible-light-driven photocatalysis,magnetic photocatalyst,Bismuth oxyhalide,pharmaceuticals and personal care products,solid solution
更新于2025-09-19 17:15:36
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Selective Laser Sintering 3D Printing of Orally Disintegrating Printlets Containing Ondansetron
摘要： The aim of this work was to explore the feasibility of using selective laser sintering (SLS) 3D printing (3DP) to fabricate orodispersable printlets (ODPs) containing ondansetron. Ondansetron was first incorporated into drug‐cyclodextrin complexes and then combined with the filler mannitol. Two 3D printed formulations with different levels of mannitol were prepared and tested, and a commercial ondansetron orally disintegrating tablet (ODT) product (Vonau? Flash) was also investigated for comparison. Both 3D printed formulations disintegrated at ~15 s and released more than 90% of the drug within 5 min independent of the mannitol content; these results were comparable to those obtained with the commercial product. This work demonstrates the potential of SLS 3DP to fabricate orodispersible printlets with characteristics similar to a commercial ODT, but with the added benefit of using a manufacturing technology able to prepare medicines individualized to the patient.
关键词： additive manufacturing,printing pharmaceuticals,orally disintegrating printlets (ODPs),3D printed drug products,personalized medicines,taste masking,three‐dimensional printing,rapid prototyping,orally disintegrating tablets (ODTs)
更新于2025-09-19 17:13:59
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Rapid Diagnosis Of Drug Agglomeration And Crystallinity In Pharmaceutical Preparations By Electrospray Laser Desorption Ionization Mass Spectrometry Imaging
摘要： In this study we evaluate the applicability of electrospray laser desorption ionization mass spectrometry imaging (ELDI-MSI) to interrogate tablet formulations for the spatial distributions of ingredients. Tablet formulations with varying amounts of crystalline acetaminophen (the active pharmaceutical ingredient, API) were analyzed to determine if crystallinity could be evaluated via ELDI-MSI. ELDI-MSI concurrently imaged the API, binders, and surfactants. The spatial distributions of amorphous API were very similar to that of the surfactants and different from that of crystalline API. The higher the crystallinity in the tablet formulation, the more agglomeration of the active ingredient was observed by ELDI-MSI. This study shows the capability of ELDI-MSI to diagnose agglomeration and crystallinity content in pharmaceutical preparations with little to no sample preparation. The ability to concurrently image APIs with other components provides valuable information as to their form in the tablet.
关键词： ELDI,crystallinity,mass spectrometry imaging,pharmaceuticals,agglomeration
更新于2025-09-11 14:15:04
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Degradation of acetaminophen in aqueous solution by UV and UV-activated sludge processes
摘要： Acetaminophen (N-acetyl-p-aminophenol, APAP) is one of the most common antipyretic analgesics used to treat common ailments throughout the world. Recently, APAP has been frequently detected in wastewater effluent and groundwater, resulting in potential risks to the environment. Current methods for eliminating APAP are complicated and cost-prohibitive. This study examined APAP degradation by ultraviolet-C (UV-C) and UV-C irradiation combined with activated sludge (UV/AS) to evaluate potential applications in wastewater treatment. The results of this study indicate that UV-C irradiation reached an APAP degradation efficiency of more than 52% and a degradation rate of 0.0012–0.0013 min?1 during 720 min of exposure, while the initial APAP concentration exhibited only a nominal effect on the degradation rate. However, the UV/AS treatment demonstrated an APAP degradation rate that was 9.6 times the rate of the UV-C-only treatment, with a degradation efficiency of 99% over the same UV irradiation period. The results further indicated that APAP photolysis efficiency was more effective when applied to sterilized AS than when applied to unsterilized AS. Finally, excessive dosage of both AS and humic acid inhibited APAP photolysis efficiency.
关键词： acetaminophen,photolysis,ultraviolet/activated sludge,ultraviolet-C,pharmaceuticals and personal care products
更新于2025-09-11 14:15:04
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Magnetically Separable BiOBr/Fe3O4@SiO2 for Visible-light-driven Photocatalytic Degradation of Ibuprofen: Mechanistic Investigation and Prototype Development
摘要： The increasingly ubiquitous release of emerging refractory pollutants into water is a serious concern due to associated risks. In this study, mesoporous hierarchical BiOBr/Fe3O4@SiO2 ― a solvothermally synthesized visible-light-driven magnetic photocatalyst ― not only exhibited fast kinetics (t1/2 = 8.7 min) in the photocatalytic degradation of ibuprofen in water but also achieved almost complete mineralization over a prolonged irradiation of 6 h. Various reactive species, including ?O2?, ?OH, and H2O2, were detected, while the scavenging experiments revealed that eCB?-mediated reactions and direct-hole oxidation are the major degradation routes. The magnetically recycled BiOBr/Fe3O4@SiO2 maintained ~80% of its initial photocatalytic activity even after five consecutive cycles. The typically co-present wastewater constituents, including NOM and anions, inhibited the photocatalytic performance to varying extents, and hence necessitated an increase in the photocatalyst dosage to achieve complete ibuprofen degradation in real sewage. Based on the findings of batch experiments, the process was scaled up by developing a 5 L prototype photocatalytic reactor integrated with an electromagnetic separation unit. The results of prototype photocatalytic experiments were comparable to those of batch experiments, and an electromagnetic separation efficiency of ~99% was achievable in 5 min.
关键词： Magnetic photocatalyst,Photocatalytic reactor,Bismuth oxyhalide,Hierarchical photocatalyst,Pharmaceuticals and personal care products
更新于2025-09-10 09:29:36
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[ACS Symposium Series] Raman Spectroscopy in the Undergraduate Curriculum Volume 1305 || Integration of Raman Spectroscopy in Undergraduate Instruction and Research at Pace University
摘要： The integration of Raman spectroscopy into undergraduate instruction and research at Pace University is discussed in this chapter. This includes the introduction of the principle of Raman instrumentation, first by theory through the use of Gaussian calculations and interpretation of readily available spectra and then using the instrument after the acquisition of a B&W Tek Miniram in 2012. The availability of the instrument allows students to expand their research in sol-gel, ionic liquid, pharmaceuticals, and biodiesel. The development of simple experiments to incorporate into laboratory classes and side-by-side comparisons of experimental results and theoretical calculations are also presented. The challenges and successes of having this instrument in our teaching facility are also described.
关键词： undergraduate instruction,ionic liquid,research,Raman spectroscopy,pharmaceuticals,sol-gel,B&W Tek Miniram,biodiesel,Pace University
更新于2025-09-04 15:30:14
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Accelerated photocatalytic oxidation of carbamazepine by a novel 3D hierarchical protonated g-C3N4/BiOBr heterojunction: performance and mechanism
摘要： A novel 3D hierarchical heterojunction of protonated g-C3N4/BiOBr was fabricated by a facile precipitation method with the protonation pretreatment of g-C3N4. The material was characterized by X-ray spectrometer (SEM), transmission electron microscopic (TEM), high resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), UV-vis reflectance spectra (UV-Vis DRS) and Brunauer-Emmett-Teller (BET). The photocatalytic activity was systematically evaluated by the degradation of carbamazepine (CBZ) under simulated solar light irradiation. The protonated g-C3N4/BiOBr with mass ratios of 5 wt% (pgB-5) achieved the optimum performance for the CBZ removal and excellent stability. The effects of some key operating parameters were further examined in detail, including photocatalyst dosage, initial solution pH, coexisting inorganic anions (HCO3-, Cl-, NO3-). The enhanced activity was ascribed to the effective charge separation occurring at the tightly contacted interface between two phases, which was revealed by electrochemical impedance spectroscopy (EIS) and photocurrent. Basing on direct evidence of the formed hydroxyl radicals (·OH), superoxide radicals (·O2-) and holes (h+) by electron spin resonance (ESR), the photocatalytic mechanism was proposed for the charge separation. The reaction intermediates were determined by liquid chromatography coupled with mass spectrometry (LC-MS) and a tentative degradation pathway of CBZ was proposed. This study provided a new insight for the design of novel 3D hierarchical heterojunctions and the degradation of recalcitrant organic contaminants in aquatic environment.
关键词： Photocatalysis,Operation parameters,Pharmaceuticals,Wastewater treatment,Heterojunction
更新于2025-09-04 15:30:14