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Vapor–liquid equilibrium (VLE) data for the systems 2-propanol + water + calcium chloride, 2-propanol + water + magnesium chloride, 2-propanol + water + calcium nitrate, and 2-propanol + water + ma...

A smart meta-superconductor Bi(Pb)SrCaCuO (B(P)SCCO) may increase the critical transition temperature (TC) of B(P)SCCO by electroluminescence (EL) energy injection of inhomogeneous phases. However, the increase amplitude ΔTC (ΔTC=TC−TC,pure) of TC is relatively small. In this study, a smart meta-superconductor B(P)SCCO with different matrix sizes was designed. Three kinds of raw materials with different particle sizes were used, and different series of Y2O3:Sm3+, Y2O3, Y2O3:Eu3+, and Y2O3:Eu3++Ag-doped samples and pure B(P)SCCO were prepared. Results indicated that the TC of the Y2O3 or Y2O3:Sm3+ non-luminescent dopant doping sample is lower than that of pure B(P)SCCO. However, the TC of the Y2O3:Eu3++Ag or Y2O3:Eu3+ luminescent inhomogeneous phase doping sample is higher than that of pure B(P)SCCO. With the decrease of the raw material particle size from 30 to 5 μm, the particle size of the B(P)SCCO superconducting matrix in the prepared samples decreases, and the doping content of the Y2O3:Eu3++Ag or Y2O3:Eu3+ increases from 0.2% to 0.4%. Meanwhile, the increase of the inhomogeneous phase content enhances the ΔTC. When the particle size of raw material is 5 μm, the doping concentration of the luminescent inhomogeneous phase can be increased to 0.4%. At this time, the zero-resistance temperature and onset transition temperature of the Y2O3:Eu3++Ag doped sample are 4 and 6.3 K higher than those of pure B(P)SCCO, respectively.

An efficient and sensitive analytical method for the simultaneous determination of five plant growth regulators (PGRs) has been successfully developed, including 3-Indoleacetic acid (IAA), 2-Naphthylacetic acid (2-NAA), Beta-indolebutyric acid (IBA), 2-(2,4-dichlorophenoxy), acetic acid (2.4-D), and 4-Chlorophenoxyacetic acid (4-CPA) in bean sprouts. Using 10% boron trifluoride of methanol as the derived reagent and the reaction was derivatized at 70 °C for 30 min, the derivatives of five PGRs have been completely separated within 19 min. It has a linear relationship in the concentration range of 0.01–0.20 mg/kg and the correlation coefficients (r2) in excess of 0.997. The average recoveries were ranged from 72.7–98.6% at three spiking different concentration levels of 0.05, 0.10, and 0.15 mg/kg, respectively. The relative standard deviations (RSDs) were ranged from 1.2 to 9.0%. The limits of detection and the limits of quantification were ranged from 0.00024 to 0.00172 mg/kg and 0.0008–0.0052 mg/kg, respectively. On the basis of these, the measurement has been successfully applied to the analysis of the exogenous phytohormones in the bean sprouts. Except for 4-CPA and IAA, the rest of the analytes were undetected in samples. In sum, the current method can be used for accurate determination and confirmation of PGRs in many other crops, such as bean sprouts.

Improving the critical transition temperature (TC) of Bi(Pb)SrCaCuO (B(P)SCCO) high-temperature superconductors is important, however, considerable challenges exist. In this study, on the basis of the metamaterial structure and the idea that the injecting energy will promote the formation of Cooper pairs, a smart meta-superconductor B(P)SCCO consisting of B(P)SCCO microparticles and Y2O3:Eu3++Ag or Y2O3:Eu3+ luminophor was designed. In the applied electric field, the Y2O3:Eu3++Ag or Y2O3:Eu3+ luminophor generates an electroluminescence (EL), thereby promoting the TC via EL energy injection. A series of Y2O3:Eu3++Ag topological luminophor-doped B(P)SCCO samples was prepared. Results showed that Y2O3:Eu3++Ag was dispersed around B(P)SCCO particles, forming a metastructure. Accordingly, the onset transition temperature (T_(C,on)) and zero resistance transition temperature (T_(C,0)) of B(P)SCCO increased. Meanwhile, the B(P)SCCO sample doped with 0.2 wt% Y2O3 or Y2O3:Sm3+ nonluminous inhomogeneous phase was also prepared to further prove the influence of EL on the T_C rather than the rare earth effect. Results indicated that the TC of the Y2O3 or Y2O3:Sm3+ doping sample decreased. However, the TC of the 0.2 wt% Y2O3:Eu3++Ag or Y2O3:Eu3+ luminophor-doped sample improved. This outcome further demonstrated that the smart metastructure method can improve the TC of B(P)SCCO.

In this study, we investigated the contamination of 123 vegetables and 130 fruits with 11 fungicides in the mid-western region of China. The index of food safety (IFS) and risk coefficient (R) were used to assess the health hazards of the fungicides to consumers. The results showed that the qualified rates of pesticide residues in fruits and vegetables were 100 % (130/130) and 98.37 % (121/123), respectively. The detection rate of pesticides in celery, cowpea, peach, and grape was higher than 70 %. The amount of difenoconazole and procymidone pesticides exceeded the standard in vegetables, while carbendazim, difenoconazole, and tebuconazole were the most common pesticides in fruits and vegetables. The IFS of all detected pesticides in the fruits and vegetables was less than 1, indicating an acceptable safety risk of the pesticide residues. The R of difenoconazole and procymidone in the vegetables was moderate, which should be considered in the key control risk factors and continuously monitored to protect people's health.

Modeling of vapor-liquid equilibrium for the aqueous solutions of formaldehyde and electrolyte is required for the extractive distillation of formaldehyde-containing multicomponent mixtures using salt as entrainers. Here a revised physicochemical model, which integrates the advantages of the physicochemical model for the vapor-liquid and the chemical equilibria in aqueous formaldehyde solution and the LIFAC model for the phase behavior in mixed-solvent electrolyte systems, has been proposed. The new vapor-liquid equilibrium data in (HCHO–H2O–salt) were systematically measured and utilized to determine newly-introduced model parameters. Comparisons of model calculated and experimental measured values proved that the model presented here provides a reliable method for correlating the vapor-liquid equilibria data in (HCHO–H2O–salt) system. Furthermore, the model established in this work was used to study salts effect on vapor-liquid equilibria. Both the model calculations and the VLE experiments uncover that Zn(NO3)2 is the most promising among all of the entrainers investigated.

In this study,an effort has been made to evaluate the pesticide residues in vegetables from western China. Fifty-one pesticides, including organophosphorus, organochlorine, carbamate and pyrethroid, were detected in 369 commonly used vegetables by GC-MS. Concentrations of organophosphorus pesticides were detected ranging from 0.0008 to 18.8200 mg/kg, among which organophosphorus pesticide concentrations exceeded their maximum residue levels (MRLs) in five samples. Carbamate and organochlorine pesticides were determined to have concentrations in the range of 0.0012-0.7928 mg/kg. The residual concentrations of carbamate pesticides in six samples and organochlorine pesticides in four samples exceeded their MRLs. The residual concentrations of five pyrethroid pesticides were within the range of 0.0016-6.0827 mg/kg and the pyrethroid residues in two samples exceeded their MRLs. The results revealed that pesticide residues in 70.73% of the vegetables samples were not detected, while in the rest of vegetables there were one or more pesticide residues and some even exceeded their MRLs, which would threaten the health of consumers. Our work provides significant information for the food safety regulations to control the excessive use of some pesticides on those kinds of vegetables from western China. Copyright © 2016 John Wiley & Sons, Ltd.

Homogeneous Y2O3:Eu3+ nanorods with the lengths of several micrometres were successfully synthesised on a large scale by using a urea-assisted hydrothermal method and a post-calcining process. In this study, the influences of urea content and NaOH concentration on the oriented growth, photoluminescence (PL) and electroluminescence (EL) intensity enhancement of Y2O3:Eu3+ were investigated. As a precipitant for isotropic growth, urea can counteract the effect of NaOH on oriented growth along the c-axis during hydrothermal treatment. The Y2O3:Eu3+ powders exhibited a strong red emission centred at 613 nm under either 245 nm UV excitation or the direct current high electric field. The PL intensity of the Y2O3:Eu3+ phosphor prepared with 0.3 g of urea reached 141 % that of the sample prepared under the same conditions but without urea. The strategy for controlling the oriented growth, PL and EL enhancement of Y2O3:Eu3+ can be extended to the synthesis of other inorganic nano/micromaterials.

The levels of multi-pesticide residues in highly consumed types of vegetables in western regions of China were investigated in this study. Vegetable samples (506) were collected from local markets from 2010 to 2013, and the concentrations of 21 types of organophosphorus (OP) and pyrethroid (PYR) pesticides from the samples were determined by gas chromatography–mass spectrometry (GC–MS). Ten OP pesticides were found in concentrations ranging from 0.0008 to 4.0544 mg/kg. Five types of PYR pesticides were determined to have concentrations in the range of 0.0009 to 6.0827 mg/kg. There were no residues in 69.76% of the samples. A portion (25.49%) of the samples contained pesticide residues less than or equal to the maximum residue limits (MRLs), and 4.94% of samples contained pesticide residues greater than their MRLs. This study provides useful information on the current contamination status of a key agricultural area in China from 2010 to 2013 and highlights the need for regular monitoring of pesticide residues in a greater number of vegetable samples and for longer periods, especially in leafy vegetables, to protect consumers.

In this work, cerium oxide nanoparticles are capable of strongly enhancing the chemiluminescence (CL) of the luminol-hydrogen peroxide (H2O2) system. Based on this, a microarray CL method for the determination of the removal rate constant of H2O2 by human erythrocytes has been developed. It is providing direct evidence for a H2O2-removing enzyme in human erythrocytes that acts as the predominant catalyst. A reaction mechanism is discussed. The proposed microarray CL method is sensitive, selective, simple and time-saving, and has good reproducibility and high throughput. Relative CL intensity is linearly related to the concentration of H2O2 in the range from 0.01 to 50 μM. The limit of detection is as low as 6.5 × 10(-11) M (3σ), and the relative standard deviation is 2. 1 % at 1 μM levels of H2O2 (for n = 11).

We developed a sensitive and robust electrogenerated chemiluminescence (ECL) flow sensor based on Ru(bpy)32+ immobilized with a Nepem-211 perfluorinated ion exchange conductance membrane, which has robustness and stability under a wide range of chemical and physical conditions, good electrical conductivity, isotropy and a high exchange capacity for immobilization of Ru(bpy)32+. The flow sensor has been used as a post-column detector in high-performance liquid chromatography for determination of erythromycin and clarithromycin in honey and pork, and tricyclic antidepressant drugs in human urine. Under optimal conditions, the linear ranges were 0.03–26 ng/μL and 0.01–1 ng/μL for macrolides and tricyclic antidepressant drugs, respectively. The detection limits were 0.02, 0.01, 0.01, 0.06 and 0.003 ng/μL for erythromycin, clarithromycin, doxepin, amitriptyline and clomipramine, respectively. There is no post-column reagent addition. In addition to the conservation expensive reagents, the experimental setup was simplified. The flow sensor was used for 2 years with high sensitivity and stability. Copyright © 2013 John Wiley & Sons, Ltd.

A simple, stable and sensitive electrogenerated chemiluminescence (ECL) detector was developed. It was based on tris(2,2-bipyridyl)ruthenium(II) (Ru(bpy)32+) immobilized on the surface of a Pt wire with Nepem-105D ion exchange solution. The detector was prepared by inserting a Pt wire with immobilized Ru(bpy)32+ (working electrode) into a capillary tube, followed by inserting another Pt wire (counter electrode) in this tube and sealing. ECL behavior was investigated using ofloxacin as an analyte. Under optimal conditions, stable ECL intensity was obtained. This detector has been used in HPLC-ECL for the determination of multiple target fluoroquinolone residues in milk. There is no post column reagent addition, which would dilute the analytes, potentially leading to chromatographic band-broadening. The system is very simple with low dead volume, low baseline and background noise, together with high sensitivity and stability. The as-prepared ECL detector, when was used for the determination of ofloxacin, pefloxacin, enrofloxacin and difloxacin in milk, demonstrated adequate sensitivity to allow quantification of trace FQ levels in commercial milk samples. One or more of the target FQ analytes were present at levels above the LOD of the new ECL detector in each and every one of the 22 milk samples analysed.

Fe3O4/polypyrrole (PPy) core/shell nanocomposite, with Fe3O4 nanoparticle as core and PPy as shell, could be facilely synthesized via in situ chemical oxidative polymerization of pyrrole monomers on the surface of Fe3O4 nanoparticles. The results indicate that core/shell nanocomposite consists of Fe3O4 core with the mean diameter of 100 nm and adjacent PPy shell with a thickness of about 70 nm. The as-prepared Fe3O4/PPy core/shell nanocomposite exhibits a saturated magnetization of 20.1 emu/g and coercivity value of 368.3 Oe, respectively. The electromagnetic characteristics of Fe3O4/PPy core/shell nanocomposite were also investigated with a vector network analyzer in the 2–18 GHz range. The absorbing peak position moves to lower frequency with increasing the thicknesses of samples. The value of the minimum reflection loss is −22.4 dB at 12.9 GHz for Fe3O4/PPy core/shell nanocomposite with a thickness of 2.3 mm, and a broad peak with a bandwidth lower than −10 dB is about 5 GHz. Such strong absorption is attributed to better electromagnetic matching due to the existence of PPy and the special core/shell structure.

We demonstrated that ZnFe2O4/polypyrrole core-shell nanoparticles could be facilely synthesized via in situ chemical oxidative polymerization of pyrrole monomers on the surface of ZnFe2O4 nanoparticles. The shell thickness of core-shell nanoparticles could be easily controlled by adjusting the amount of pyrrole monomers. The phase structures, morphologies and properties of the as-prepared products were investigated by XRD, TEM, SEM, VSM, and FTIR spectra. Magnetic studies revealed that the saturation magnetization (Ms) and coercivity (Hc) of ZnFe2O4/PPy core-shell nanoparticles is 17.8 emu/g and 130 Oe, respectively. The electromagnetic characteristics of products showed that ZnFe2O4/PPy core-shell nanoparticles exhibit excellent microwave absorption performance than ZnFe2O4 nanoparticles, such as more powerful absorbing property and wider electromagnetic wave absorbing frequency band due to the proper matching of the permittivity and the permeability of ZnFe2O4/PPy core-shell nanoparticles.

Uniform lanthanum hydroxide nanorods were successfully synthesized in large quantities through a facile hydrothermal synthetic method, in which soluble lanthanum nitrate was used to supply the lanthanum source and triethylamine (TEA) was used as both alkaline agent and complexing agent. The influences of triethylamine amount, surfactant, reaction temperature and time on the size and shape of lanthanum hydroxide nanorods were investigated in detail. Trivalent rare earth ion doped lanthanum hydroxide nanorods were also obtained in this paper. The phase structures and morphologies of the as-prepared products were investigated in detail by X-ray diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (SAED) and high-resolution transmission electron microscopy (HRTEM). The probable formation mechanism was proposed based on the experimental results.

Monodisperse Zn ferrite nanospheres and its Ba substitution nanosheets were successfully prepared by a facile solvothermal method. The size, morphology, and structure of the as-prepared products were investigated in detail by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), and inductively coupled plasma atomic emission spectroscopy (ICP-AES). Magnetic studies revealed that Zn ferrite nanospheres are ferrimagnetic with a saturation magnetization ( M s ) of 49.6 emu /g and M s increased from 49.6 emu /g to 84.2 emu /g when Ba2+ was substituted into Zn ferrite to form BaZn ferrite nanosheets. To explain the variations of morphology and magnetic properties, the strong preferential occupancy of cations in chemically equivalent A and B sites and the metastable cation distribution in nanoparticles are invoked.

The practical methods were developed for the simultaneous determination of benzoic acid (BA) and sorbic acid (SA) in sour snap bean samples containing oil. BA and SA in the samples were extracted by ultrasonication with water, followed by cleanup procedures with precipitation for removing the potential proteins and with petroleum ether liquid-liquid extraction for removing the edible oil contained in the samples. The HPLC method was developed using Supelco C18 (250 mm x 4.6 mm id, 5 microm) as column, MeOH-20 mM NH(4)Ac (25:75 v/v) at 1.0 mL/min as the mobile phase and 230 nm as the detection wavelength. The optimal NACE method was established with a running buffer of 20.0 mM NH(4)Ac in 95% MeOH (pH* 10.6), and an applied voltage of -30 kV over a capillary of 50 microm id x 48.5 cm (40 cm to the detector window), which gave a baseline separation of BA and SA, and as well as of the blank matrix within ca. 10 min. Both HPLC and NACE methods gave the relatively lower limits of quantification at about 0.01-0.02 and 0.04-0.05 mg/kg, respectively, whereas the overall recoveries were larger than 85.0%. The proposed methods have been successfully applied to measure 15 real sour bean samples and the content profile of BA and SA in sour bean samples was obtained and evaluated.

Mitral valvular disease is strongly related to atrial fibrillation (AF), but the different types of mitral valvular disease have a different prevalence of AF. In this study we explored the expressions of the circulating and local renin-angiotensin-aldosterone system (RAAS) in order to determine the relationship between circulating and local RAAS expressions and its effects on AF in different types of mitral valvular disease patients. Our study group consisted of 24 mitral valvular disease patients scheduled for mitral valve replacement surgery. Peripheral blood samples and left atrial appendage tissue samples were obtained from all patients. Radioimmunoassay was performed to assess the expression levels of circulating and local renin, angiotensin II and aldosterone. In mitral valvular diseases, linear correlation analyses were done for local and circulating renin, angiotensin II and aldosterone; the p values were 0.979, 0.518 and 0.125, respectively. Expression levels of local angiotensin II, circulating angiotensin II and local aldosterone were significantly increased in the AF group compared with sinus rhythm; the p values were 0.023, 0.042 and 0.035, respectively. In mitral stenosis patients, AF was primarily associated with local angiotensin II ( p =0.010), as well as being associated with circulating angiotensin II ( p =0.038). In mitral regurgitation patients, AF was only significantly associated with local angiotensin II ( p =0.038). Circulating and local RAAS expressions are associated with AF in mitral valvular disease patients. The levels of circulating and local RAAS expressions were different in AF patients with different types of mitral valvular diseases. The differentiation of circulating and local RAAS expression levels in AF patients between different types of mitral valvular disease can potentially improve the specific pharmacological interventions outcomes for these patients.

This work presents a new chemiluminescent (CL) probe array assay. The new type CL probe array is based on enzyme mimics of Co3O4-SiO2 mesoporous nanocomposite material, which not only have an excellent catalytic effect on the luminol-H2O2 CL reaction in an alkaline medium but also can be used for the immobilization of enzymes. The linear range of the lactose concentration is 3.0 × 10(-7) to 1.0 × 10(-5) g mL(-1) and the detection limit is 6.9 × 10(-8) g mL(-1). β-Galactosidase and glucose oxidase were selected as a model for enzyme assays to demonstrate the applicability of Co3O4-SiO2 mesoporous nanocomposite material in multienzyme immobilization. The novel bifunctional CL probe array has been successfully applied to the determination of lactose in milk.

A new chemiluminescent (CL) probe array assay approach was first developed. The new CL probe array was based on Co 3 O 4 –SiO 2 mesoporous nanocomposite material, which not only has an excellent catalytic effect on the luminol–H 2 O 2 CL reaction in alkaline medium but also can be used for the immobilization of enzymes. As a model, the novel bifunctional CL probe array has been applied to the high-throughput determination of glucose in human. The linear range of the glucose concentration was 3–90 μM and the detection limit was 0.36 μM. It breaks traditional development view in solid phase supports and provides new insights into the application of mesoporous material.

We have demonstrated previously that acute nerve compression produces ischemia/reperfusion injury in rat sciatic nerve. In this study, we evaluated the effects of deferoxamine, an antioxidant, on recovery from ischemia/reperfusion injury after nerve compression. The sciatic nerves of male Sprague-Dawley rats, 370 to 430 g, were subjected to 24 hours of compression with Silastic tubing. The control group received intravenous saline solution at the time of decompression. The therapeutic group received intravenous deferoxamine (50 mg per kilogram) at the time of removal of the Silastic tubing. Nerve tissues within and distal to the compression site were assayed for malondialdehyde (MDA) levels and for growth-associated protein 43 (GAP-43) expression, as markers of ischemia/reperfusion injury and nerve regeneration, respectively. In the control group (injury alone), the MDA levels were three times higher than normal during the initial 10 days and returned to normal by 14 days. In contrast, the deferoxamine treatment group had MDA levels that were not significantly different from precompression levels. In the control group, enhanced GAP-43 expression persisted until late in the recovery period. In the deferoxamine treatment group, the increased GAP-43 expression subsided early. The results suggest that the treatment of compressed peripheral nerve with deferoxamine at the time of surgical decompression reduces ischemia/reperfusion injury.

To deal with the problem of carbon source lacking and the difficulties of waste activated sludge (WAS) disposal in wastewater treatment plant (WWTP), nitrite was added into WAS fermentation system (NSF) to develop a new way to accomplish denitrification and WAS reduction simultaneously in this paper, and the effect of electron acceptor concentration (200, 400, 600, and 800 mg/L nitrite) on denitrification in NSF was studied. Experiment results showed that different NO2--N concentration of NSF systems presented different denitrification ability, the best denitrification performance was found in 400 mg/L, and it was investigated that the nitrite removal amount per unit of volatile suspended solid (VSS) reduction in different NSF systems was presented as this order: 400>600>200>800 (mg/L), with values of 0.66, 0.60, 0.46, 0.44 mg NO2--N /mgVSS-reduction respectively. Furthermore, there was no volatile fatty acids (VFAs) accumulation in 400mg/L NO2--N concentration system, while different level of accumulation in other NO2--N concentration systems was found, which meant denitrifiers in 400mg/L NSF could utilize carbon sources much better than that of others. Additionally, all the systems showed a great sludge reduction capacity, with more than 40% of VSS reduction.

We proposed a novel pH measurement method based on two-photon fluorescence excitation of a dual-wavelength pHsensitive dye combined with scanning near-field optical microscopy (SNOM) that can be used to evaluate mitochondrial activity. Mitochondria produce ATP using a proton concentration (pH) gradient generated between both sides of their inner membrane. Thus, pH distribution around mitochondria can change with time when mitochondria produce ATP. This pH distribution has attracted interest because of its influence on necrotic cell death. Because ATP depletion causes necrotic cell death, measurement of pH distribution around mitochondria is expected to lead to clarification of the mechanism underlying necrotic cell death. However, it is very difficult to accurately measure pH around mitochondria using conventional pH measurement methods. In this study, a dual-wavelength pH-sensitive dye was excited locally using two-photon fluorescence excitation. In addition, collection-mode SNOM was used to avoid reabsorption by collecting the fluorescent light directly from a florescence point. Using this method, we successfully calibrated pH and observed temporal variations in pH after dropwise addition of acid. Moreover, mitochondrial activity was successfully observed based on these pH changes.

A novel method to observe pH distribution by dual wavelength fluorescent ratiometric pH measurement by scanning near-field optical microscopy (SNOM) is developed. In this method, in order to investigate not only the pH of mitochondrial membrane but also its distribution in the vicinity, a pH sensitive fluorescent reagent covers mitochondria instead of injecting it to mitochondria. This method utilizes a dual-emission pH sensitive dye and SNOM with a themally-pulled and metal-coated optical fiber to improve the spatial resolution. Time-dependence of Fluorescent intensity ratio (FIR) under acid addition is investigated. As the distances between the dropped point and the SNOM probe becomes closer, the time when FIR changes becomes earlier. The response of mitochondria under supplement of nutrition is studied by using this method. While the probe is near to mitochondria, the ratio quickly becomes to increase. In conclusion, it was confirmed that the temporal variation of pH can be detected by this method, and pH distribution in the vicinity of mitochondria is able to be measured by this method.

Six calixarene bonded silica gel stationary phases were prepared and characterized by elemental analysis, infrared spectroscopy and thermal analysis. Their chromatographic performance was investigated by using PAHs, aromatic positional isomers and E- and Z-ethyl 3-(4-acetylphenyl) acrylate isomers as probes. Separation mechanism based on the different interactions between calixarenes and analytes were discussed. The chromatographic behaviors of those analytes on the calixarene columns were influenced by the supramolecular interaction including pi-pi interaction, space steric hindrance and hydrogen bonding interaction between calixarenes and analytes. Notably, the presence of polar groups (-OH, -NO(2) and -NH(2)) in the aromatic isomers could improve their separation selectivity on calixarene phase columns. The results from quantum chemistry calculation using DFT-B3LYP/STO-3G* base group were consistent with the retention behaviors of PHAs on calix[4]arene column.

A practical method for residue analysis of 2,4-D, dicamba and 2,4,5-T in baked tobacco leaves has been developed using nonaqueous CE (NACE). The herbicide residues of 2,4-D, dicamba and 2,4,5-T in tobaccos were extracted by ultrasonication with ethyl acetate, followed by a cleanup procedure with gel permeation chromatography. The separation of 2,4-D, dicamba and 2,4,5-T by NACE was optimized based on orthogonal experiment design with four factors at three levels. The optimal NACE condition was established with the running buffer of 40.0 mmol/L ammonium acetate in 90% CH3CN (apparent pH 10.2), and the applied voltage of -25 kV over a capillary of 50 microm id x 46 cm (37.5 cm to the detector window), which gave a baseline separation of 2,4-D, dicamba and 2,4,5-T within 15 min. The LOD were ca. 0.4-0.6 microg/mL for the three herbicides, whereas the overall recovery ranged from 80.8 to 84.1%. The proposed method has been successfully applied to measure 300 real tobacco samples, and the residue profiles of the three herbicides in tobacco samples were obtained and evaluated.

A mitochondrion has a pH gradient between the two sides of its inner membrane in order to produce adenosine triphosphate (ATP). Because ATP depletion causes numerous diseases, the measurement of the pH value around the mitochondrion is expected to clarify the mechanism of these diseases. In this study, a dual-wavelength pH-sensitive dye was excited by two-photon absorption initiated using a femtosecond pulse laser. In addition, fluorescence from the dye was directly collected from the fluorescent point using the collection-mode probe of a scanning near-field optical microscope. By this proposed method, a pH calibration curve was obtained from the fluorescent intensity ratio of the dye solution, and temporal pH variations with 0.1 s time resolution following the addition of acid were observed. Moreover, mitochondrial activity on the basis of the pH changes was successfully observed in three different mitochondrial densities.

In this work, a simple method based on reverse-phase high-performance liquid chromatography (HPLC) with tris(2,2-bipyridyl)ruthenium(II) [Ru(bpy)32+]-modified single Pt wire electrogenerated chemiluminescence (ECL) detector for the determination of three antiemetic drugs was developed. The proposed detector was based on Ru(bpy)32+ immobilized on a Pt wire surface with Nepem-105D ion exchange solution. The method allows for the simultaneous detection of these antiemetic drugs in human serum and offers short analysis times. In this HPLC-ECL system, luminescence reagent Ru(bpy)32+ was immobilized, thus, no Ru(bpy)32+ delivery system is needed, furthermore, stable ECL response of analytes can obtained. Besides conserving the expensive reagent, the experimental setup is also simplified.