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The interactions of isonicotinamide (INA) with seven common solvents (acetic acid, acetonitrile, acetone, chloroform, ethyl acetate, and methanol) have been studied to examine solute-solvent effects on the nucleation of INA from these solvents. In a simple model of 1:1 solute-solvent interactions, the strongest INA-solvent interaction is with acetic acid (binding energy, ΔEbind = -64.05 kJ mol-1) and the weakest is with chloroform (ΔEbind = -24.85 kJ mol-1). This arises since acetic acid and INA form a hydrogen-bonding motif containing two moderate strength N-H···O hydrogen bonds, while chloroform and INA have a single weak C-H···O hydrogen bond. Taking acetic acid, chloroform, and methanol, the solvents with the strongest, the weakest, and an intermediate strength INA-solvent binding energy, the solvation of INA was studied to compare it with the 1:1 model. Acetic acid has the strongest binding energy (-872.24 kJ mol-1) and solvation energy (-341.20 kJ mol-1) with chloroform binding energy (-517.72 kJ mol-1) and solvation energy (-199.05 kJ mol-1). Methanol has intermediate binding energy (-814.19 kJ mol-1) and solvation energies (-320.81 kJ mol-1). These results further confirm the recent the findings which indicate that the key trends in solvent-solute interactions can be determined from a simple and efficient 1:1 dimer model and can be used to predict ease of nucleation with stronger binding energies correlating to slower, more difficult nucleation. A limit of this model is revealed by considering alcohol and acid solvents with longer alkyl chains. [ABSTRACT FROM AUTHOR]

The application of homogeneous transition metal catalysts offers various advantages for chemical processes, such as mild reaction conditions and high selectivity. The main drawback is the difficult recovery of these precious catalysts, so that a small loss of catalyst can cause economic insufficiency of a chemical process. Our approach for overcoming this challenge is the application of two different catalyst recovery techniques, which are combined in a so-called hybrid separation process. Here, a thermomorphic solvent system is used for the recovery of the precious rhodium catalyst in a first stage, and a subsequent organic solvent nanofiltration unit is used in a second stage. [ABSTRACT FROM AUTHOR]

A modified synthetic method with a high definition visual camera technique for measuring the solubility of solutes in solvents or mixed solvents was proposed. To verify the reliability of the experimental apparatus, the solubility of NH4Cl in water was determined at different temperatures. The relative standard errors were less than 1%, compared to the literature data. The solubilities of betulonic acid in six organic solvents from (278.15 to 313.15) K were measured and correlated with the Apelblat equation and universal quasichemical equation, respectively. The modified method was quite concise and user-friendly, and made the process of dissolution to become visualized and automatic. [ABSTRACT FROM AUTHOR]

A phage-displayed library of variable domain of heavy chain of the heavy chain antibody (VHH) or nanobody (Nb) was constructed after immunizing an alpaca with aflatoxin B1 (AFB1) conjugated with bovine serum albumin (AFB1-BSA). Two AFB1-specific nanobodies were selected. The obtained nanobodies were compared to an aflatoxin-specific monoclonal antibody B5 with respect to stability under organic solvents and high temperature. The two nanobodies could bind antigen specifically after exposure to temperatures as high as 95 °C. Besides, the nanobodies showed better or similar tolerance to organic solvents. A competitive ELISA with nanobody Nb26 was developed for the analysis of AFB1, exhibiting an IC50 value of 0.754 ng/mL (2.4 μM), linear range from 0.117 to 5.676 ng/mL. Due to the high tolerance to methanol, sample extracts were analyzed by nanobody-based ELISA without dilution. The recovery from spiked peanut, rice, corn and feedstuff ranged from 80 to 115%. In conclusion, the isolated nanobodies are excellent candidates for immunoassay application in aflatoxin determination. [ABSTRACT FROM AUTHOR]

The determination of water in various matrices is one of the most important analytical measurements. We report on a high-resolution capacitance-based moisture sensor utilizing a thin film of a perfluorosulfonate ionomer (PFSI)-H3PO4 composite in a flow-through configuration, for both gas and liquid samples. Incorporation of H3PO4 into a PFSI sensing film improved the limit of detection (LOD) (signal-to-noise ratio, S/N = 3) by a factor of 16 in the gas phase to 0.075% relative humidity (RH) (dew point = -56 °C). The response time was dependent on the sensing film thickness and composition and was as low as 60 ms. The temperature dependence of the sensor response, and its relative selectivity over alcohol and various other solvents, are reported. Measurement of water in organic solvents was carried out in two different ways. In one procedure, the sample was vaporized and swept into the detector (e.g., in a gas chromatograph (GC) without a column); it permitted a throughput of 80 samples/h. This is well-suited for higher (%) levels of water. In the other method, a flow injection analysis system integrated to a tubular dialysis membrane pervaporizer (PV-FIA) was used; the LOD for water in ethanol was 0.019% (w/w). We demonstrated the temporal course of drying of ethanol by Drierite; the PV-FIA results showed excellent correspondence (r2 > 0.99) with results from GC-thermal conductivity detection. The system can measure trace water in many types of organic solvents; no reagent consumption is involved. [ABSTRACT FROM AUTHOR]

The densities and speeds of sound for ternary mixtures of methyl methacrylate (MMA) + 1-alkanols (1-butanol, 1-pentanol, 1-heptanol) + aromatic organic solvents (benzene, toluene, p-xylene, and ethylbenzene) or + cyclohexane have been measured at T/K = (298.15 and 308.15). Excess molar volumes and excess isentropic compressibilities were calculated across the mole fraction range, and the same were compared with the values calculated using similar data for the binary pairs through Redlich−Kister (RK), Tsao and Smith (TS), and Kohler (K) equations. As compared to others, the RK equation predicted the excess molar volumes and excess isentropic compressibilities adequately. [ABSTRACT FROM AUTHOR]