Influence of storage humidity on the in vitro inhalation properties of salbutamol sulfate dry powder with surface covered lactose carrier

The influence of storage humidity on the in vitro inhalation properties of salbutamol sulfate dry powder with surface covered lactose carrier was investigated. In the present study, drug/carrier powder mixtures were prepared consisting of micronized salbutamol sulfate and lactose carriers with different particle surface conditions prepared by surface covering. Lactose carrier surfaces were covered with vegetable magnesium stearate (Mg-St-V) by a high-speed elliptical-rotor-type powder mixer (Theta-Composer). These powder mixtures were aerosolized by a Jethaler), and the in vitro inhalation properties of salbutamol sulfate were evaluated by a twin impinger. Compared with the powder mixed with uncovered lactose carrier, the in vitro inhalation properties of the powder mixture prepared using the surface covered lactose carrier were little decreased with increased in relative humidity (RH), showing that the in vitro inhalation properties of salbutamol sulfate were improved at high RH. Using this surface covering technique would thus be valuable for storage humidity of dry powder inhalation (DPI) with lactose carrier particles.     

Thermal transitions in and structures of dried polyelectrolytes and polyelectrolyte complexes

Dynamic mechanical analysis (DMA) was used to explore the thermomechanical properties of dried polyelectrolytes and polyelectrolyte complexes (PECs) with different thermal and humidity histories. Although differences in the amount of water remaining in polyelectrolytes and PECs were small for ambient versus dessicator storage, the properties of polyelectrolyte‐based materials were drastically different for different humidity histories. Glass transition temperatures (T_gs) of poly(diallyldimethylammonium chloride) (PDADMAC) were shown to vary by 100 °C, depending on humidity and thermal histories. These parameters also change glassy storage modulus values by 100%. Furthermore, we observe that dried PDADMAC is highly lossy. DMA of dried poly(styrene sulfonate) (PSS) was more complex and did not exhibit a glass transition in the tested range. DMA of a PEC of PDADMAC and PSS revealed a humidity history‐dependent water melt in the first heating cycle, as well as storage modulus values of dried and annealed PECs that only varied by 17–26% over a 275 °C temperature range. Based on these results, we report for the first time humidity history as controlling structure and properties of polyelectrolyte‐based materials. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017 , 55, 684–691     

Controlling electrospun nanofiber morphology and mechanical properties using humidity

Electrospinning is a fiber spinning technique used to produce nanoscale polymeric fibers with superior interconnectivity and specific surface area. The fiber diameter, surface morphology, and mechanical strength are important properties of electrospun fibers that can be tuned for diverse applications. In this study, the authors investigate how the humidity during electrospinning influences these specific properties of the fiber mat. Using two previously uninvestigated polymers, poly(acrylonitrile) (PAN) and polysulfone (PSU) dissolved in N,N‐Dimethylformamide (DMF), experimental results show that increasing humidity during spinning causes an increase in fiber diameter and a decrease in mechanical strength. Moreover, surface features such as roughness or pores become evident when electrospinning in an atmosphere with high relative humidity (RH). However, PAN and PSU fibers are affected differently. PAN has a narrower distribution of fiber diameter regardless of the RH, whereas PSU has a wider and more bimodal distribution under high RH. In addition, PSU fibers spun at high humidity exhibit surface pores and higher specific surface area whereas PAN fibers exhibit an increased surface roughness but no visible pores. These fiber morphologies are caused by a complex interaction between the nonsolvent (water), the hygroscopic solvent (DMF), and the polymer. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2011     

Determination of terpenes in humid ambient air using ultraviolet ion mobility spectrometry

Atmospheric humidity causes the major problem using ion mobility spectrometers (IMS) under ambient conditions. Significant changes of the spectra are decreasing sensitivity as well as selectivity. Therefore, the influence of humidity on the IMS signal was investigated in case of direct introduction of the analyte into the ionisation chamber and in case of pre-separation by help of a multi-capillary column (MCC). For direct analyte introduction, a significant decrease of the total number of ions in the range of 28-42% with increasing relative humidity was found. Simultaneously additional peaks in the spectra were formed, thus complicating the identification of the analytes. In case of pre-separation of the analyte, the spectra do not change with increasing relative humidity, due to the successive appearance of the analyte and the water molecules in the ionisation chamber. Detection limits were found in the range of 5 μg/m³ (about 1 ppbv) for selected terpenes and—with pre-separation—independent on relative humidity of the analyte. Without pre-separation, detection limits are in the same range for dry air as carrier gas but in the range of 200-600 μg/m³ when relative humidity reaches 100%. Thus, MCC-UV ion mobility spectrometry is optimally capable for the detection of trace substances in ambient air (e.g. indoor air quality control, process control, odour detection) without further elaborate treatment of the carrier gas containing the analyte and independent on relative humidity.     

Effects of humidity and surface on photoalignment of brilliant yellow

Controlling and optimising the alignment of liquid crystals is a crucial process for display application. Here, we investigate the effects of humidity and surface types on photoalignment of an azo-dye brilliant yellow (BY). Specifically, the effect of humidity on the photoalignment of BY was studied at the stage of substrate storage before coating, during the spin-coating process, between film coating and exposure, and after exposure. Surprising results are the drastic effect of humidity during the spin-coating process, the humidity annealing to increase the order of the BY layer after exposure and the dry annealing to stabilise the layer. Our results are interpreted in terms of the effect of water on the aggregation of BY. The type of surface studied had minimal effects. Thin BY films (about 3 nm thickness) were sensitive to the hydrophilicity of the surface while thick BY films (about 30 nm thickness) were not affected by changing the surface. The results of this paper allow for the optimisation of the BY photoalignment for liquid crystal display application as well as a better understanding of the BY photoalignment mechanism.     

Crystallinity and fluorine substitution effects on the proton conductivity of porous hydroxyapatites

Porous calcium hydroxyapatite (p-HAp) was prepared by wet chemical methods. The poorly crystalline structure and the high surface specific area (235 m²/g) of this hydroxyapatite have effects on the variation of the electrical properties. Good linearity of logarithm of conductivity versus the relative humidity in the range from 19% to 88% (RH) was observed using the complex impedance spectroscopy. The proton conduction was affected by the relative humidity related to H₂O adsorption on the material surfaces. The fluorine substitution in p-HAp also modifies the crystalline and the proton conduction properties.     

An experimental investigation of evaporation time and the relative humidity on a novel positively charged ultrafiltration membrane via dry–wet phase inversion

In this paper, a novel positively charged asymmetrical membrane was manufactured from brominated polyphenylene oxide (BPPO)/N-methyl-2-pyrrolidone (NMP)/H₂O via in situ amination with triethanolamine (TEOA) and a dry–wet phase inversion. The casting solution was exposed to the humid surroundings before immersing into the coagulation bath. The positive charge character of the membrane surface was examined by streaming potential and the effect of the evaporation time and the relative humidity (RH) on the membrane properties and microstructure were investigated, respectively. It was interestingly found that the role of evaporation time and the relative humidity on the membrane performance and morphologies for a positively charged casting system was different from the conventional rule. This was mainly due to the competition of two influence factors, i.e., evaporation of solvent and water absorption of the casting solution. The results were conformed to SEM observation and pore size distribution. Furthermore, the process of water absorption of the casting solution was monitored by attenuated total reflectance infrared (ATR-FTIR) spectroscopy technique. Additionally, in order to compare to the dry–wet phase inversion method, the membranes were obtained by prolonging the exposure time to more than 12 h (which was similar to vapor-induced phase inversion) at different RH. Polymer nodules on the membrane surface and a symmetrical morphology were observed by SEM.     

黏结剂对铁酸锌脱硫剂在高温煤气中脱硫性能的影响

以硝酸铁、硝酸锌、氨水及黏结剂为主要原料,用共沉淀法制成六种铁酸锌脱硫剂。研究了各种黏结剂的加入对脱硫剂的尖晶石结构、硫容量和脱硫效果的影响,在固定床上对其进行脱硫试验。并用X射线衍射（XRD）、扫描电子显微镜(SEM)和气体吸附等测试手段,对脱硫剂的物相组成、结构、比表面积和孔容进行了表征。结果表明,用共沉淀法制备的铁酸锌,具有不受黏结剂影响的尖晶石结构,其颗粒属于微米级;添加高岭土黏结剂的脱硫剂的脱硫效果最好,添加硅藻土的脱硫剂的脱硫效果最差;不同黏结剂对脱硫剂的织构的影响不同;脱硫剂的反应活性和硫容量与其孔容的大小有关。     

MIL-125(Ti)及其氨基功能化材料修饰石英晶体微天平的湿敏性能

采用简单的溶剂热法制备金属有机框架化合物MIL-125(Ti)和NH_2-MIL-125(Ti)材料,并通过X射线衍射仪、扫描电子显微镜、傅氏转换红外线光谱分析仪和比表面积测试仪对所得样品进行表征。将2种材料修饰构建为石英晶体微天平传感器,测试其在11%～97%RH相对湿度范围内的湿度感测性能。实验结果表明,基于MIL-125(Ti)和NH_2-MIL-125(Ti)构建的传感器对湿度具有灵敏度高、重复性好、响应/恢复快等特点。相对于没有氨基修饰的MIL-125(Ti),NH_2-MIL-125(Ti)材料修饰的传感器对湿度表现出更高的响应性能。在环境湿度约52%时,NH_2-MIL-125(Ti)传感器对11%RH湿度响应值比MIL-125(Ti)湿度传感器的大57 Hz,说明氨基功能化对MIL-125(Ti)的湿敏性能有显著的增强作用。此外,通过Materials Studio模拟计算获得了水分子与MIL-125(Ti)及NH_2-MIL-125(Ti)作用的吸附焓,也证明氨基功能化对MIL-125(Ti)的湿度敏感性能具有增强作用。     

Effect of technique of applying layers of metal acetylacetonates on acid-base and chromatographic properties of sorbents

A series of chromatographic sorbents, which differ by way of applying modifying chelates of acetylacetone was obtained. The acid-base and chromatographic properties of sorbents with thermally and chemically grafted layers of metal acetylacetonates were investigated. It was shown that the modifi cation of the mineral sorbents with metal acetylacetonates leads to a change in the surface acidity, as well as to an increase in the polarity and selectivity with respect to different classes of compounds.     

Influence of Surfactant and Humidity on Sol-Gel Macroporous Organosilicate Coatings

In the preparation of macroporous hydrophobic organosilicate films using methyltriethoxysilane (MTES) as precursor, the effects of surfactant addition, surfactant properties and atmospheric humidity were explored. As films dried, preferential evaporation of the ethanol resulted in an increase of the relative water content. This led to development of phase separation between the hydrophobic gel and the aqueous liquid and ultimately the formation of macropores. In the presence of surfactant, surfactant adsorption at the aqueous phase/gel interface affected the extent of phase separation therefore the resulting pores. Span 20 surfactant (HLB = 8.6) has lower compatibility with the aqueous phase than Tween 20 (HLB = 16.7) and effectively increases the hydrophobicity of the gel phase leading to the formation of larger pores. An increase in Span 20 content from 2 wt.% to 5 wt.% also increased pore size. Film porosity also increased significantly with humidity inside the coating chamber. It would appear that the increased porosity is a result of increased phase separation caused by reduced water evaporation at the higher humidity. Highly macroporous (up to 80% porosity), reproducible and uniform films were obtained by incorporating Span 20 surfactant into the coating solutions and performing dip coating at 80% relative humidity.     

Preparation and characterization of double metal-silica sorbent for gas filtration

This paper presents the preparation of a porous (Mg, Ca) silicate structure, which could be employed as sorbent filter media. The sorbents have been prepared using sodium silicate precipitated with various ratios of magnesium and calcium salts. The sorbents obtained were characterized using scanning electron microscope (SEM), X-ray diffraction (XRD) and nitrogen physisorption isotherm. Further, the applicability and performance of the sorbent impregnate with potassium hydroxide for removal of sulphur dioxide (SO₂) has been demonstrated. From the isotherms, specific surface area, pore diameter and volume of pores were estimated. Results show that the chemical composition and textural properties of the resultant sorbents were highly dependent on Mg/Ca molar ratio. It was found that sorbents made with 68 mol% Mg and 32 mol% Ca (PSS-MgCa-68/32); and 75 mol% Mg and 25 mol% Ca (PSS-MgCa-75/25) exhibited even higher specific surface area and pore volume than the sorbents containing a single metal. The Mg/Ca-silica sorbents obtained contains interconnected bimodal porosity with large portions being mesopores of varied sizes. The pore size distribution (PSD) results further indicate that PSS-MgCa-68/32 sorbent exhibits wide PSD of interconnected pores in the size range of 1 to 32 nm while PSS-MgCa-50/50 and PSS-MgCa-75/25 exhibits narrow PSD of 1 to 5 nm. Using SO₂ as model contaminate gas, it was shown that the dynamic adsorption performance of the PSS-MgCa-sorbents impregnated with 8 wt% KOH exhibits SO₂ uptake, with impregnated PSS-MgCa-68/32 showing better performance. This shows that the materials prepared can be used as adsorbent for gas filtration.     

A study of the adsorption properties of the hypercross-linked polystyrene sorbents Styrosorb by gas chromatography. Effect of the conditioning temperature

The effect of the conditioning temperature of the hypercross-linked polystyrene sorbents Styrosorb on the retention ofn-hexane, benzene. and acetone was studied by gas chromatography. The rigid but mobile structure of 100% cross-linked polymers with a specific surface area of 300–500 m² g⁻¹ prepared in cyclohexane slightly shrinks by conditioning above 200 °C. This results in a significant increase in the specific retention volumes of the adsorbates. The commercial hypercross-linked sorbents MN-100 and MN-200 with specific surface areas of −1000 m² g⁻¹ retain their structure up to 250 °C. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1502–1506, August. 1999.     

Surface-layer composite sorbents for the rapid preconcentration of volatile organic substances from aqueous solutions and gas atmospheres

The regularities of the dynamic sorption of volatile organic substances from aqueous solutions and atmospheric air on surface-layer composite sorbents, in which a finely dispersed sorption-active material is retained due to adhesion on the surface of a relatively coarsely dispersed macroporous carrier, were determined. The analytical capabilities of such sorbents were studied, and they were found more effective than traditional porous bulk sorbents used for the concentration of volatile organic compounds from aqueous solutions and gas atmospheres.     

Application of inverse gas chromatography in the characterization of raw material used in manufacturing of abrasive materials

The raw material—aloxite used during the manufacturing of grinding tools was characterized by means of inverse gas chromatography (IGC). The surface properties of the different types of aloxite were determined including: (i) the specific surface area; (ii) the dispersive component of surface free energy as well as the sensitivity of this parameter on the environment humidity; and (iii) acidity and basicity of the examined surfaces. The results of our experiments proved the usefulness of IGC in the characterization of this kind of materials.     

Dispersive solid-phase microextraction method for sample extraction in the analysis of four tetracyclines in water and milk samples by high-performance liquid chromatography with diode-array detection

A dispersive solid-phase microextraction (dispersive-SPME) method for the determination of tetracycline, oxytetracycline, chlortetracycline and doxycycline is proposed. Different silica-based and polymeric sorbents were evaluated for their capacity to simultaneously preconcentrate tetracyclines (TCs) in the dispersive format from aqueous or organic solutions. Silica-based sorbents especially functionalized with primary amine, secondary amine, or carbonyl groups have showed higher capacity than polymeric sorbents under organic environment. In the proposed dispersive solid-phase microextraction method, after extraction with acetonitrile and salt-promoted partitioning, TCs were adsorbed to a small amount of dispersive silica-based primary and secondary amine sorbents, desorbed with a small volume of desorption solution, and determined by high-performance liquid chromatography with diode-array detection. Under the optimal conditions, recoveries were determined for surface water and milk samples spiked at 10 ng/mL and 50–150 ng/g, respectively, and quantification was achieved by matrix-matched calibration. The calibration curves of four TCs in both samples showed linearity with a correlation coefficient value above 0.997. Average recoveries ranged from 97.1 to 104.1% and the precision was from 2.0 to 5.6%. Limits of detection ranged from 0.7 to 3.5 ng/mL and from 7.9 to 35.3 ng/g for four TCs surface in surface water and milk samples, respectively.     

Sorption interactions of volatile organic compounds with organoclays under different humidities by using linear solvation energy relationships

Organoclays are usually used as sorbents to reduce the spread of organic compounds and to remove them at contaminated sites. The sorption equilibrium and the mechanisms of volatile organic compounds (VOCs) on organoclays under different humidities are helpful for developing efficient organoclays and for predicting the fate of VOCs in the environment. In this study, the organoclay was synthesized through exchanging inorganic cations by hexadecyltrimethyl ammonium (HDTMA) into montmorillonite, resulting in 12?% of organic content. The surface area of organoclay was smaller than the unmodified clay due to the incorporation of organic cations into the interlayer. Both adsorption on organoclay surface and partition into the incorporated HDTMA in organoclay played roles on the sorption process. Compared the sorption coefficients in montmorillonite and different modified clays, the incorporated organic cations overcame the inhibition effect of hydrophilic surface of clay on the sorption process of hydrophobic organic compounds from water. The sorption coefficients of VOC vapors on organoclay were further characterized using a linear solvation energy relationship (LSER). The fitted LSER equations were obtained by a multiple regression of the sorption coefficients of 22 probe chemicals against their solvation parameters. The coefficients of the five-parameter LSER equations showed that high HDTMA-content montmorillonite interacts with VOC molecules mainly through dispersion, partly through dipolarity/polarizability and hydrogen-bonds as well as with negative π-/n-electron pair interaction. The interaction analysis by LSERs suggests that the potential predominant factors governing the sorption of VOCs are dispersion interactions under all tested humidity conditions, similar with the lower level modified clay. The derived LSER equations successfully fit the sorption coefficients of VOCs on organoclay under different humidity conditions. It is helpful to design better toxic vapor removal strategy and evaluate the fate of organic contaminants in the environment.     

Complex-Emulsion synthesis of organo-inorganic amphiphilic sorbents with specific affinity for glucose

Granular organo-inorganic amphiphilic sorbents with specific affinity for glucose were synthesized with the aim of developing selective hemosorbents for efferent therapy of hyperglycemia. The sorbents were prepared in oil/water/oil complex emulsions by copolymerization of 2-hydroxyethyl methacrylate and ethylene glycol dimethacrylate on the surface of selenium nanoparticles stabilized with polyvinylpyrrolidone. The phases were stabilized with excess selenium/polyvinylpyrrolidone nanocomplexes. Optimum synthesis conditions ensuring formation of hybrid sorbents with the physicochemical properties required for performing efficient preparative hemosorption and plasma adsorption processes were found. The specific affinity for glucose was reached by modification of these sorbents via imprinting with template glucose molecules in the surface polymer layer and via introduction of boric acid as an affine ligand into the hybrid matrices.     

Development of a multi-residue analytical method,based on liquid chromatography–tandem mass spectrometry,for the simultaneous determination of 46 micro-contaminants in aqueous samples

A multi-residue analytical method based on high-performance liquid chromatographic separation, electrospray ionization with tandem mass spectrometric detection (HPLC/MS–MS) was developed for the simultaneous analysis of 46 basic, neutral and acidic compounds covering a wide range of polarity (log K_OW < 0–5.9). The compound list included selected iodinated contrast media, analgesics, anti-inflammatories, stimulants, beta-blockers, antibiotics, lipid regulators, anti-histamines, psychiatric drugs, herbicides, corrosion inhibitors and the gastric acid regulator pantoprazole. The main feature of the presented method was a simultaneous solid phase extraction (SPE) of all analytes followed by simultaneous separation and detection by HPLC/MS–MS with electrospray ionization in both positive and negative polarization within the same chromatogram. Optimization of electrospray drying gas temperature resulted in using a temperature gradient on the ion source. Six different polymeric sorbents for SPE were compared with respect to recoveries, taking into account the specific surface of each sorbent. Method quantitation limits (MQL) in surface and seawater ranged from 1.2 to 28 ng/L, in wastewater from 5.0 to 160 ng/L, respectively. In order to demonstrate the applicability of the method, river water, treated wastewater and seawater were analyzed.     

Properties and Application of a Chelating Sorbent Prepared by Modification of LiChroprep-NH<Subscript>2</Subscript> with Calcon

A new chelating sorbent for metal ions was prepared by modification of chemically modified silica – LiChroprep-NH₂ with Calcon. The molecular mechanism of binding this reagent to the surface of the applied carrier is presented. The properties of this sorbent were compared to analogous sorbents with a plain silica carrier and chemically modified silicas – LiChroprep-RP containing Calcon. The advantages of the new sorbent compared to the silica and LiChroprep-RP chelating sorbents are demonstrated. The sorbent obtained was applied as stationary phase in solid-phase extraction (SPE) for separations of some chosen mixtures of metal ions and for additional purification of aqueous solutions of salts of alkali metals from trace amounts of heavy metals. The multiple use of the sorbent based on LiChroprep-NH₂ in sorption-desorption processes of metal ions without deterioration of its sorption capacity is demonstrated.