Facile Synthesis of Quinoline-Substituted 3-Hydroxy-2-oxindoles and 3-Amino-2-oxindoles via a Palladium-Catalyzed Cascade Intramolecular Cyclization/Intermolecular Nucleophilic Addition Reaction.

An efficient cascade intramolecular cyclization/intermolecular nucleophilic addition reaction of allenyl benzoxazinone with isatin or isatin-derived ketimine has been established by using Pd0-π-Lewis base catalysis. A series of 3-hydroxy-2-oxindoles and 3-amino-2-oxindoles with quaternary carbon atoms at the C3 position were synthesized in good yields under mild conditions through this protocol.

A rapid hydrophilic interaction liquid chromatographic determination of glimepiride in pharmaceutical formulations.

Glimepiride is one of the most widely prescribed antidiabetic drugs and contains both hydrophobic and hydrophilic functional groups in its molecules, and thus could be analyzed by either reversed-phase high performance liquid chromatography (HPLC) or hydrophilic interaction liquid chromatography (HILIC). In the literature, however, only reversed-phase HPLC has been reported. In this study, a simple, rapid and accurate hydrophilic interaction liquid chromatographic method was developed for the determination of glimepiride in pharmaceutical formulations. The analytical method comprised a fast ultrasound-assisted extraction with acetonitrile as a solvent followed by HILIC separation and quantification using a Waters Spherisorb S5NH2 hydrophilic column with a mobile phase consisting of acetonitrile and aqueous acetate buffer (5.0 mM). The retention time of glimepiride increased slightly with decrease of mobile phase pH value from 6.8 to 5.8 and of acetonitrile content from 60% to 40%, indicating that both hydrophilic, ionic, and hydrophobic interactions were involved in the HILIC retention and elution mechanisms. Quantitation was carried out with a mobile phase of 40% acetonitrile and 60% aqueous acetate buffer (5.0 mM) at pH 6.3, by relating the peak area of glimepiride to that of the internal standard, with a detection limit of 15.0 µg/L. UV light absorption responses at 228 nm were linear over a wide concentration range from 50.0 µg/L to 6.00 mg/L. The recoveries of the standard added to pharmaceutical tablet samples were 99.4-103.0% for glimepiride, and the relative standard deviation for the analyte was less than 1.0%. This method has been successfully applied to determine the glimepiride contents in pharmaceutical formulations.

Isolation and screening of carboxydotrophs isolated from composts and their potential for butanol synthesis.

Carboxydotrophs are known for their ability to convert carbon monoxide (CO) to butanol through fermentation. Such a platform offers a promising alternative approach to biofuel production from synthesis gas feedstocks. In this study, carboxydotrophs were isolated from various manure compost. Out of 500 isolates, only 11 carboxydotrophs (7 mesophiles and 4 thermophiles) were found to utilize CO as the sole source of carbon and energy. To assess the biochemical basis for their ability to produce biofuel (butanol), the level of activities of CO dehydrogenase (CODH), hydrogenase and butanol dehydrogenase (BDH) enzymes for these isolates against the known carboxydotroph, Butyribacterium methylotrophicum was assessed. All isolates showed evidence of enzyme activities (0.16-2.20 micromol min(-1)), with the majority exhibiting higher activities compared with the known carboxydotroph, B. methylotrophicum (0.33-0.71 micromol min(-1)). The level of activities for CODH and BDH ranged from 0.163-3.59 micromolmin(-1) and 0.19-2.2 micromolmin(-1), respectively. Three isolates (M7-1, T2-22, and T3-14) demonstrated enzymatic activity three to seven times higher than B. methylotrophicum. Of these, T2-22 exhibited the highest BDH activity and shows great promise in the conversion of toxic CO into butanol more so than other carboxytotrophs known thus far. This study revealed some biochemical basis for butanol production from CO by carboxydotrophs. However, more research is needed to discover a direct biological route for butanol production from CO to strengthen their potential for synthesis gas bioprocessing. Follow-up work will focus on whole-genome sequencing of the promising isolate T2-22 to provide system-level insights into how carboxydotrophs utilize and regulate their molecular machineries for butanol production.

Determination of cocaine on banknotes using innovative sample preparation coupled with multiple calibration techniques.

A method using innovative sample preparation was developed for determination of cocaine on banknotes. Aqueous extraction of cocaine from banknotes was performed using a sonication-enhanced technique. Quantitation of cocaine was achieved using high performance liquid chromatography (HPLC) with UV detection at 230 nm, whereas identification was accomplished utilizing gas chromatography with mass spectrometry (GC-MS). Multiple calibration techniques, including the external calibration method (ECM), internal standard method (ISM), and standard addition method (SAM) were incorporated into the experimental design to simultaneously determine cocaine contents and assess matrix effects. Statistical paired t tests confirmed that matrix effects were not significant with the sample preparation employed. No damage to the features of the banknotes was observed from the extraction procedure. Extraction efficiency, spike recovery, and detection limit were also determined. The unique experimental design allowed for ECM, ISM, and SAM to concurrently determine the contents of cocaine on banknotes collected around Metro-Detroit. The concentration range of cocaine was from 1.58 to 14.7 µg per note, with an average of 6.96 µg per note. The method is simple and suitable for drug analysis and forensic science applications.

Simultaneous determination of anthraquinones in radix Polygoni multiflori by capillary gas chromatography coupled with flame ionization and mass spectrometric detection.

A rapid, accurate and reliable analytical method was developed for the simultaneous determination of five major anthraquinones, aloe-emodin, chrysophanol, emodin, physcion, and rhein, in radix Polygoni multiflori, a traditional Chinese herbal medicine. The method comprises a fast ultrasonic extraction with methanol and derivatization with N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA)+1% trimethylchlorosilane (TMCS) followed by capillary gas chromatographic (GC) separation. The effect of reaction time on the derivatization of anthraquinones was examined. A baseline separation of the anthraquinone and internal standard derivatives was achieved in 15min. The detection limits range from 0.22 to 0.60microg/mL for the five anthraquinones. The calibration curves are linear over the concentration range studied (from the detection limits to 40.0microg/mL) with the squares of correlation coefficients, R2, greater than 0.998. The developed method was successfully applied to the simultaneous determination of anthraquinones in radix P. multiflori samples. The peak identification was confirmed using GC-MS. The contents of anthraquinones in radix P. multiflori samples studied were 27.41, 289.6, 64.22, 202.1, 288.6microg/g for chrysophanol, emodin, aloe-emodin, physcion, rhein, respectively. All relative standard deviations are less than 3.2%. The recoveries range from 80.2% to 119.3% for the five analytes. To the authors' best knowledge, this is the first GC method reported for the simultaneous determination of the five anthraquinones in radix P. multiflori.

Trace elements in atmospheric wet precipitation in Detroit metropolitan area: Levels and possible sources.

Rain and snow samples were collected in the Detroit metropolitan area and analyzed by inductively coupled plasma-mass spectrometry (ICP-MS). Twenty-two elements were detected in a concentration range from ∼0.03 to ∼1.8 × 103 µg/kg. An enrichment factor (EF), defined as, EF=(X/Al)sample(X/Al)crust , was estimated for each element (X) detected, and used to determine possible origins of the element. Based on the hypothesis that crustal material is the only source of aluminum (Al) found in the atmospheric environment, an EF value near unity for an element suggests that crustal material is a major source of this element. If EF>10, an element is enriched in the atmosphere relative to its concentration in the earth's crust, implying a source other than the crust. Alkali, alkaline earth and lanthanide metals detected in the samples exhibit low EF values, indicating mainly a crustal source. Six elements (As, Cd, Cu, P, Pb and Zn) were significantly enriched in the samples as their EF values were greater than 10, thus originated likely from anthropogenic emissions. The relative order of the significantly enriched elements is estimated as follows: Cd > Pb > Zn > As > Cu > P. A high enrichment (EF∼100) for phosphorus was observed and caused plausibly by extensive usage of phosphorus-containing fertilizers and pesticides.

Occurrence and photochemical degradation of 17alpha-ethinylestradiol in Acushnet River Estuary.

17alpha-Ethinylestradiol (EE2), a major constituent of common contraceptive pills, and three other estrogenic hormones, estrone (E1), 17beta-estradiol (E2) and mestranol (MeEE2) have been determined in Acushnet River Estuary seawater using a GC-MS technique. Among three estrogenic compounds detected, EE2 has the highest concentration, up to 4.7 ng/l, at which EE2 may affect lobster and other fish abundance in the coastal seawater due to its high biological activity on fish feminization. Two natural estrogenic hormones, E1 and E2 have also been found in the estuary at concentrations up to 1.2 ng/l and 0.83 ng/l, respectively. Although EE2 is persistent to microbial degradation, it can undergo a rapid photodegradation in estuarine seawater under natural sunlight irradiation, with a half-life of less than 1.5 days in spring sunny days.

Determination of creatinine, uric and ascorbic acid in bovine milk and orange juice by hydrophilic interaction HPLC.

Creatinine (Cr), uric (UA) and ascorbic acid (AA) are common constituents in human fluids. Their abnormal concentrations in human fluids are associated with various diseases. Thus, apart from the endogenous formation in human body, it is also important to examine their sources from food products. In this study, a rapid and accurate HILIC method was developed for simultaneous determination of Cr, UA and AA in bovine milk and orange juice. Milk samples were pretreated by protein precipitation, centrifugation and filtration, followed by HPLC separation and quantification using a Waters Spherisorb S5NH2 column. The developed method has been successfully applied to determine the concentration of UA, AA and Cr in milk and fruit juice samples. The milk samples tested were found to contain UA and creatinine in the concentration range of 24.1-86.0 and 5.07-11.2 µg mL(-1), respectively. The orange juices contain AA over 212 µg mL(-1).

Separation and identification of aromatic acids in soil and the Everglades sediment samples using solid-phase microextraction followed by capillary zone electrophoresis.

The separation and identification of aromatic acids in soil and the Everglades sediment samples was carried out using solid-phase microextraction (SPME) followed by capillary zone electrophoresis (CZE). The soil and sediment samples were subject to a series of sample treatments including oxidative hydrolysis with molecular oxygen in a sodium hydroxide solution, acidification and filtration. The aromatic acids in the sample filtrate were extracted using SPME with a polyacrylate-coated fiber. The acids adsorbed on the fiber were subsequently desorbed in methanol. The desorbed acids were then separated by CZE. Several aromatic acids (e.g.. salicylic acid, p-coumaric acid, ferulic acid and vanillic acid) in both soil and sediment samples were separated, identified and quantified. The results of this study show that the combination of SPME with CZE is promising for environmental analysis.

Absorption and excretion of cranberry-derived phenolics in humans.

Absorption and excretion of twenty cranberry-derived phenolics were studied following the consumption of cranberry juice, sauces, and fruits by healthy human volunteers. Plasma and urine samples were collected and analysed by gas chromatography-mass spectrometry (GC-MS). A high performance liquid chromatography (HPLC) method was employed for analysing urinary creatinine, which was used as a normalisation agent. Significant increases in the sum of plasma phenolics were observed with different concentration peaks (between 0.5 and 2h) for individual subjects. Some of the phenolics, such as trans-cinnamic, vanillic, p-coumaric acids, and catechin showed second plasma concentration peaks. All of cranberry-derived phenolics increased significantly in urine samples after the intake of each cranberry product. The high molecular weight quercetin and myricetin, which were abundant in cranberry foodstuffs, were not found in either plasma or urine samples. This study provided the fundamental information for understanding the absorption and excretion of phenolics in the human gastrointestinal system after dietary intake of cranberry products.

Simultaneous determination of catechins, caffeine and gallic acids in green, Oolong, black and pu-erh teas using HPLC with a photodiode array detector.

A simple and fast HPLC method using a photodiode array detector was developed for simultaneous determination of four major catechins, gallic acid and caffeine. After multiple extractions with aqueous methanol and acidic methanol solutions, tea extract was separated within 20 min using a methanol-acetate-water buffer gradient elution system on a C(18) column. The sample extraction data demonstrated that the single extraction used in the previous studies with aqueous acetonitrile or methanol is not sufficient; the multiple extraction procedure is essential for the quantitative analysis of catechins, phenolic acids and caffeine in teas. Several green, Oolong, black and pu-erh teas were successfully analyzed by this method. The analytical results obtained indicated that green teas contain higher content of catechins [(-)-epigallocatechin gallate, (-)-epigallocatechin, (-)-epicatechin gallate, and (-)-epicatechin] than both Oolong, pu-erh and black teas because fermentation process during the tea manufacturing reduced the levels of catechins significantly. The fermentation process also remarkably elevated the levels of gallic acid in full-fermented pu-erh and black teas. Another interesting finding is the low level of caffeine in Oolong teas, especially in Fujian Oolong tea.