A rapid automated method for wine analysis based upon sequential injection (SI)-FTIR spectrometry

A new process control methodology for the simultaneous determination of sugars, alcohols and organic acids in wine based on multivariate evaluation of mid-IR transmission spectra of wine samples is presented. In addition to ethanol several lower level wine components (glucose, fructose, glycerol, citric-, tartaric-, malic-, lactic- and acetic acid) were determined. To establish a multivariate calibration model a set of 72 calibration solutions was prepared and measured, using a novel, fully automated sequential injection (SI) system with Fourier transform infrared (FTIR) detection. The resulting spectra were evaluated using a partial least square (PLS) model. The developed PLS model was then applied to the analysis of real wine samples containing 79–91 g L^–1 ethanol, 5.9–8.1 g L^–1 glycerol, 0.4–6.9 g L^–1 glucose, 1.5–7.5 g L^–1 fructose, 0.3–1.6 g L^–1 citric acid, 1.0–1.7 g L^–1 tartaric acid, 0.02–3.2 g L^–1 malic acid, 0.4–2.8 g L^–1 lactic acid and 0.15–0.60 g L^–1 acetic acid, yielding results which were in good agreement with those obtained by an external reference method (HPLC-IR). The short analysis time (less than 3 min) together with high reproducibility makes the newly developed method applicable to process control and screening purposes (average of the standard deviations calculated from four repetitive measurements of six different real samples: ethanol: 0.55 g L^–1, glycerol: 0.037 g L^–1, glucose: 0.056 g L^–1, fructose: 0.036 g L^–1, citric acid: 0.020 g L^–1, tartaric acid: 0.010 g L^–1, malic acid: 0.052 g L^–1, lactic acid: 0.012 g L^–1 and acetic acid: 0.026 g L^–1). Received: 21 January 1998 / Revised: 5 March 1998 / Accepted: 6 March 1998     

Simultaneous GC-MS quantitation of acids and sugars in the hydrolyzates of immunostimulant, water-soluble polysaccharides of basidiomycetes

Summary The simultaneous quantitation of acids and sugars as their trimethyl silyl (TMS) derivatives has been extended in order to identify and quantitate the simple acid and sugar constituents in the hydrolyzates of various immunostimulant, water-soluble polysaccharides obtained from various Basidiomycetes, such as Armillariella mellea, Auricularia auricula-judae, Coriolus versicolor, Flammulina velutipes, Fomes fomentarius, Ganoderma applanatum, Ganoderma lucidum, Pleurotus ostreatus, Schizophyllum commune, Trametes hirsuta. Optimum hydrolysis conditions, performed with 2 M trifluoroacetic acid (TFAA) for five hrs, proved the presence of several sugars and acids with maximum recovery. (i) the total sugar/sugar alcohol content of polysaccharides varied between 20- and 65% and consisted of arabitol (0.01–10.2%), arabinose (0.09–1.3%), ribose (0.2–1.8%), fucose (0.3–1.2%), mannitol (0.01–5.3%), sorbitol (0.01–0.05%), galactiol (0.04%), fructose (0.08–0.8%), galactose (0.9–29%), glucose (10–53%), uronic acids (0.14–3.7%), sucrose (0.03–2%), trehalose (0.2–1%), cellobiose (0.01–0.6%), maltose (0.2–1.9%), other disaccharides (0.2–8%). (ii) The total of acids varied from 1.5 to 30% including o-phosphoric (1.3–19%), malic (0.08–4.7%), citric (0.08–4.7%), isocitric; (3%) and C₁₆−C₁₈ fatty acids (1–6%).     

Thermal degradation of poly(lactic acid) measured by thermogravimetry coupled to Fourier transform infrared spectroscopy

Thermogravimetric (TG), differential thermal analysis (DTA) and thermal degradation kinetics, FTIR and X-ray diffraction (XRD) analysis of synthesized glycine–montmorillonite (Gly–MMT) and montmorillonite bound dipeptide (Gly–Gly–MMT) along with pure Na–MMT samples have been performed. TG analysis at the temperature range 25–250 °C showed a mass loss for pure Na–MMT, Gly–MMT and Gly–Gly–MMT of about 8.0%, 4.0% and 2.0%, respectively. DTA curves show the endothermic reaction at 136, 211 and 678 °C in pure Na–MMT whereas Gly–MMT shows the exothermic reaction at 322 and 404 °C and that of Gly–Gly–MMT at 371 °C. The activation energies of the first order thermal degradation reaction were found to be 1.64 and 9.78 kJ mol⁻¹ for Gly–MMT and Gly–Gly–MMT, respectively. FTIR analyses indicate that the intercalated compounds decomposed at the temperature more than 250 °C in Gly–MMT and at 250 °C in Gly–Gly–MMT.     

Exploring the Role of C–H….π Interactions on the Structural Stability of Single Chain “All-Alpha” Proteins

C–H….π interactions are known to be important contributors to protein stability. In this study, we have analyzed the influence of C–H….π interactions in single chain “all-alpha” proteins. In the data set, a total of 181 C–H….π interactions were observed. The most prominent representatives are the interactions between aromatic C–H donor groups and aromatic π acceptors. Eighty-one percent of the C–H….π interactions between side chain to side chain and remaining19% of the C–H….π interactions were observed between side-chain to side-chain five-member aromatic ring. The donor atom contribution to C–H….π interactions was mainly from Phe, Tyr, and Trp residues. The acceptor atom contribution to C–H….π interactions was mainly from Phe, Tyr, Trp, and His. The highest percentage of C–H….π interactions were observed form Phe residue. The secondary structure preference analysis of all C–H….π interacting residues showed that Phe, Tyr, Trp, and His preferred to be in helix. Long-range C–H….π interactions are the predominant type of interactions in single chain all-alpha proteins data set. All the C–H….π interactions forming residues in the data set preferred to be in the buried region. Seventy-three percent of the donor residues and 65% of the acceptor residues are highly conserved.     

Synthesis of Amido- and Diamidophosphites with Polyfluoroalkyl Substituents

Bis(polyfluoroalkyl) chlorophosphites and polyfluoroalkyl dichlorophosphites react easily with secondary amines (from –40 to –22°C, 1–3 h, CH2Cl2) in the presence or absence of triethylamine to form the corresponding bis(polyfluoroalkyl) diorganylamidophosphites or bis(diorganylamido) polyfluoroalkyl phosphites in the yield of up to 74%. Bis(polyfluoroalkyl) diorganylamidophosphites were also synthesized from diorganylamidodichlorophosphites and polyfluoroalkanols (–25 to –22°C, 2 h, Et3N–CH2Cl2) with a yield of 56–60%.     

The effect of CH<Subscript>3</Subscript>, F and NO<Subscript>2</Subscript> substituents on the individual hydrogen bond energies in the adenine–thymine and guanine–cytosine base pairs

The substituent effects on the geometrical parameters and the individual hydrogen bond (HB) energies of base pairs such as X–adenine–thymine (X–A–T), X–thymine–adenine (X–T–A), X–guanine–cytosine (X–G–C), and X–cytosine–guanine (X–C–G) have been studied by the quantum mechanical calculations at the B3LYP and MP2 levels with the 6–311++G(d,p) basis set. The electron withdrawing (EW) substituents (F and NO₂) increase the total binding energy (ΔE) of X–G–C derivatives and the electron donating (ED) substituent (CH₃) decreases it when they are introduced in the 8 and 9 positions of G. The effects of substituents are reversed when they are located in the 1, 5, and 6 positions of C, with exception of CH₃ in the 1 position and F in the 5 position, which in both cases the ΔE value decreases negligibly small. With minor exceptions (X=8–CH₃, 8–F, and 9–NO₂), both ED and EW substituents increase slightly the ΔE values of X–A–T derivatives. The individual HB energies (∆E _HBs) have been estimated using electron densities that calculated at the hydrogen bond critical points (HBCPs) by the atoms in molecules (AIM) method. Most of changes of individual HBs are in consistent with the ED/EW nature of substituents and the role of atoms entered H-bonding. The remarkable change is observed for NO₂ substituted derivative in each case.     

Resonance light-scattering method for the determination of BSA and HSA with sodium dodecyl benzene sulfonate or sodium lauryl sulfate

A new resonance light-scattering (RLS) assay of proteins such as bovine serum albumin (BSA) and human serum albumin (HSA) is presented. In the medium of phosphoric acid (pH=2.6), the weak RLS of sodium dodecyl benzene sulfonate (SDBS) or sodium lauryl sulfate (SLS) can be greatly enhanced by proteins, owing to interaction between the protein and the anionic surfactant and formation of an associate. The RLS intensity of the SDBS–protein system is stronger than that of the SLS–protein system under same experimental conditions. It is considered that the synergistic resonance caused by the absorption of both protein and SDBS could produce strong RLS, while absorption of protein only in the SLS system could cause relatively weak RLS. The enhanced intensity of RLS is proportional to the concentration of the protein. If SDBS is used as the probe the linear range is 7.5×10^–9–1.5×10^–5 g mL^–1 for BSA and 1.0×10^–8–1.0×10^–5 g mL^–1 for HSA. The detection limits are 1.8 and 2.8 ng mL^–1, respectively. When SLS is used as the probe the linear range is 2.0×10^–8–1.0×10^–5 g mL^–1 and 2.5×10^–8–1.0×10^–5 g mL^–1 for BSA and HSA, respectively, and the detection limits are 12.8 and 21.6 ng mL^–1, respectively. The biological mimics samples are synthetic concoctions of BSA and HSA with some interferents. In these samples, the concentration of interferents is higher than the concentration normally existing in organisms. The samples were determined satisfactorily.     

An Enhanced Adsorption in Puerarin Retention on Oligo-β-Cyclodextrin Grafted Poly(Glycidyl Methacrylate) Media

The poly(glycidyl methacrylate) adsorbents P(GMA–EDMA) and P(GMA–DVB) were synthesized by the radical suspension–polymerization method and farther coupled by oligo-β-cyclodextrin (CDP) to obtain P(GMA–EDMA)–CDP and P(GMA–DVB)–CDP. The synthesized polymeric media were characterized by Fourier transform infrared (FTIR) spectrometer, scanning electron microscopy, and BET surface area. The adsorption of puerarin from aqueous solution onto the four media, i.e., P(GMA–EDMA), P(GMA–DVB), P(GMA–EDMA)–CDP, and P(GMA–DVB)–CDP, was studied. An enhanced adsorption of puerarin apparently presented on grafted media. The interaction between the polymeric media and the puerarin was researched by FTIR. The result shows that the adsorption efficiency on P(GMA–DVB)–CDP driven by multiple weak interactions is much higher than that on P(GMA–EDMA) driven by hydrogen bonding interaction only and on P(GMA–DVB) or P(GMA–EDMA)–CDP driven by two interactions.     

Essential oil ofPeucedanum oreoselinum fruits collected near Vilnius

Fruits ofPeucedanum oreoselinum (L.) Moench, were collected at three sites in 1995–1998 and contained 1.5–5.0% essential oil. Analyses were performed using GLC and GC-MS. The main component of the essential oil is limonene (44.1–82.4%). The majority of examined samples contained more limonene than has been reported in the literature. Only in sunny locations do plants synthesize significant quantities of γ-terpinene (12.2–17.5%) and β-pinene (8.5–14.5%). Small quantities of α-pinene are present in all studied samples of essential oil (4.0–8.3%). Monoterpenes comprise 97.1–98.6% of the essential oil. The remainder consists of sesquiterpenes. Institute of Chemistry, ul. Goshtauto, 9, Vilnius, Lithuania. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 743–745, November–December, 1999.     

Influence of Second-Order Lines on the Quantitative Wavelength Dispersive Spectrometry Analysis at Low Accelerating Voltages

The study covers a problem frequently encountered in the quantification of the results of wavelength-dispersive spectrometry (WDS) for the composition analysis of thin films. The characteristics of a Parallel Beam Spectrometer and traditional WDS systems were examined and olivine mineral – (Mg, Fe)₂SiO₄ (O – 44.03 wt%, Mg – 31.1 wt%, Si – 19.56 wt%, Fe – 5.06 wt%, Ni – 0.16 wt%, Mn – 0.09 wt%) was used as a reference material. Low accelerating voltage at 7 kV and beam current 400 nA were applied. Both methods yielded 30–35% of Mn. This is attributed to the overlapping of the MnLα first-order and the MgKα second-order lines. Studies of the influences of the second- and the third-order lines show that the second-order lines from Kα and Lα X-ray counts affected significantly the obtained WDS spectra when the influence of Mα counts was insignificant. Furthermore, the third-order lines did not have a marked effect on the analysis results.     

Synthesis,characterization and visible-light photocatalytic activity of TiO2–SiO2 composite modified with zinc porphyrins

Three types of silica gel supported titanium dioxide particles immobilizing Zn(II) carboxylphenyl porphyrins appending p-CH₃, p-H and p-Cl phenyl substituents (designated as ZnMP–TiO₂–SiO₂, ZnPP–TiO₂–SiO₂ and ZnCP–TiO₂–SiO₂, respectively) have been synthesized and characterized using SEM, XRD, IR, AFS, DRS, UV–Vis, XPS and TG. The photodegradation of α-terpinene in aqueous suspension was used to determine the photocatalytic activity of TiO₂–SiO₂ samples which had been impregnated with Zn(II) porphyrins, as sensitizers. The experimental results confirmed that the photocatalytic activitys of these composites are much higher than those of the nonmodified TiO₂–SiO₂ under visible light irradiation and follow the order of ZnMP–TiO₂–SiO₂ > ZnPP–TiO₂–SiO₂ > ZnCP–TiO₂–SiO₂.     

Synthesis and Electrochemical Behavior of Some 1H-3-Methyl-4-ethoxycarbonyl-5-(benzylidenehydrazino)pyrazoles

Summary. 1H-3-Methyl-4-ethoxycarbonyl-5-(benzylidenehydrazino)pyrazoles are key intermediates in obtaining various heterocyclic systems including pyrazolotriazoles. We present the voltammetric behavior of these compounds in nonaqueous media, with the following para substituents grafted on the benzene ring: –N(CH₃)₂, –OH, –OCH₃, –F, –Cl, –CF₃, –NO₂, as well as of the novel compounds with –Br, –I, and –SCH₃ in the para position, in order to elucidate the influence of the various substituents on the mechanism of anodic oxidation.     

Synthesis and Electrochemical Behavior of Some 1H-3-Methyl-4-ethoxycarbonyl-5-(benzylidenehydrazino)pyrazoles

1H-3-Methyl-4-ethoxycarbonyl-5-(benzylidenehydrazino)pyrazoles are key intermediates in obtaining various heterocyclic systems including pyrazolotriazoles. We present the voltammetric behavior of these compounds in nonaqueous media, with the following para substituents grafted on the benzene ring: –N(CH₃)₂, –OH, –OCH₃, –F, –Cl, –CF₃, –NO₂, as well as of the novel compounds with –Br, –I, and –SCH₃ in the para position, in order to elucidate the influence of the various substituents on the mechanism of anodic oxidation.     

XRF Analysis of Microsamples of Semiconductor Type Multielement Materials by the Thin Layer Method. Determination of Cr, Co, Ni, Cu, Zn, Ga, Se, Sb, Yb

 A simple and quick method of durable samples preparation by the thin layer method through direct digesting of the analysed material on the substrate has been presented. Four- and three-component mono- and polycrystals have been analysed. Standards have been used in calibration containing: Cr, Co, Ni, Cu, Zn, Ga, Se, Sb, Yb. To improve the correlation between the concentration and the fluorescent radiation models of mathematical corrections have additionally been used: multiple linear regression, Lucas-Tooth-Pyne model (L. T. P.) and de Jongh model (d. J.). Statistical parameters: detection limits for 0.5 mg samples: Cr–0.041%, Co–0.034%, Ni–0.042%, Cu–0.053%, Zn–0.054%, Ga–0.057%, Se–0.057%, Sb–0.113%, Yb–0.077%. Correlation coefficients: simple regression 0.9946–0.9997, multiple regression 0.9974–1.0000, L. T. P. 0.9993–1.0000, d. J. 0.9995–1.0000. Received August, 1, 1998. Revision March 25, 1999.     

Chemical variation in leaf oils of Pistacia chinensis from five locations in China

Hydrodistilled leaf oils of Pistacia chinensis Bunge from five locations in China were analyzed using GC/MS. A total of 58 compounds was identified in the oils, and a relatively high variation in their contents was found. The major compounds include β-phellandrene (0.54–53.86%), α-pinene (4.74–54.44%), β-pinene (0.49–42.90%), caryophyllene (5.64–20.01%), cis-ocimene (tr−43.93%), eudesmadiene (0–15.06%), and camphene (tr−20.57%). Cluster analysis classified the leaf oils into two chemotypes: one rich in α-pinene and β-pinene, and the other rich in β-phellandrene. Published in Khimiya Prirodnykh Soedinenii, No. 4, pp. 341–343, July–August, 2006.     

Hematological health-related intervals estimated using an indirect method in order to satisfy the accreditation standards

 The estimation of reference limits represents quite a taxing task for laboratories which frequently adopt the limits suggested by manufacturers or those reported in the literature. This practice does not meet the requirements of accreditation programs (i.e. Essential Criteria, Clinical Pathology Accreditation) that require laboratories to produce or check all their reference intervals. We collected 15 244 hematological results from females aged 0–99 years obtained by the Rovereto Hospital Laboratory and calculated the reference intervals, or to be more precise the health-related intervals, using an indirect method (based on all the inpatient and outpatient results). All the measurements were carried out using an automatic Coulter STK S analyzer, and the results were transferred to Verona by e-mail. The results for hemoglobin were: <1 year (n=154)=90–171 g/l; 2–8 years (n=619)=104–136 g/l; 9–14 years (n=322)=118–143 g/l; 15–44 years (n=6329)=106–144 g/l; 45–75 years (n=4893)=107–148 g/l; 75–99 years (n=2927)=90–153 g/l. The results appear different from the results currently used by Rovereto Hospital (120–160 g/l) but comparable to those reported in the literature with the exception of the subjects under 1 year and over 75 years, probably due to the excess of "diseased" subjects in these classes. The indirect method allows even small laboratories to produce or check their reference intervals for all age groups, increasing the clinical effectiveness of laboratory results and satisfying the accreditation standards. Received: 15 April 2000 · Accepted: 20 April 2000     

Conductivities of Several Ternary Electrolyte Solutions and Their Binary Subsystems at 293.15, 298.15, and 303.15 K

Conductivities were measured for the ternary systems NaNO₃–KNO₃–H₂O, NaCl–BaCl₂–H₂O, NaCl–LaCl₃–H₂O, and their binary subsystems NaNO₃–H₂O, KNO₃–H₂O, NaCl–H₂O, BaCl₂–H₂O, and LaCl₃–H₂O at (293.15, 298.15 and 303.15) K. The results were used to verify the generalized Young’s rule and the semi-ideal solution theory. Comparison of the results shows that the average relative differences between the predicted and measured conductivities are ≤4.2×10⁻³ for NaNO₃–KNO₃–H₂O, ≤4.6×10⁻³ for NaCl–BaCl₂–H₂O, and ≤8.9×10⁻³ for NaCl–LaCl₃–H₂O, indicating that the generalized Young’s rule and the semi-ideal solution theory can provide good predictions for the conductivity of mixed electrolyte solutions in terms of the data from their binary subsystems.     

Quantification of human and veterinary antibiotics in water and sediment using SPE/LC/MS/MS

An analytical method was developed and tested for four different groups of veterinary antibiotics in both river water and sediment matrices. Solid phase extraction (SPE) was used to enrich and to clean up the aqueous sample. Also, Mcllvaine and ammonium hydroxide buffer solutions were used to extract the compounds from the sediment matrix. High performance liquid chromatography (HPLC) equipped with tandem mass spectrometry (MS/MS) was used to separate and quantify the samples. The range of recoveries (in percent) for tetracyclines (TCs), sulfonamides (SAs), macrolides (MLs), and ionophore polyethers (IPs) in the water matrix were 102.2–124.8, 76.6–124.3, 89.5–114.7, 82.7–117.5 with 1–13 (%) of relative standard deviation respectively with three different concentrations. For sediment, the percent recovery ranges were 32.8–114.8, 62.4–108.9, 53.4–128.4 and 51.3–105.4 for TCs, SAs, MLs and IPs, respectively. The relative standard deviation ranged from 16 – 27 (%) over three different concentrations. The limit of quantification (LOQ) was determined by two different methods and calculated to be in the range of 0.01–0.04 μg/l and 0.3–2.5 μg/kg for TCs, SAs, and MLs in water and sediment, respectively. For IPs, the LOQ was 0.001–0.003 μg/l in river water and 0.4–3.6 μg/kg for sediment. The sediment concentration measured in an agriculture-influenced river was much higher than in the overlying water matrix, indicating a high degree of sediment partitioning for these compounds.     

Chemical deposition and characterization of thin polypyrrole films on glass plates: role of organosilane treatment

 Thin chloride-doped polypyrrole films (PPyCl) were deposited chemically onto untreated and silane-treated planar glass plates from aqueous solutions. The organosilanes used to treat the glass substrates were methyltriethoxysilane (Cl), propyltrimethoxysilane (C3), octyltrimethoxysilane (C8) and aminopropyltriethoxysilane (APS). The decreasing order of hydrophobic character of silane-treated glass slides, as measured by water contact angle measurements, was glass–APS ≅ glass–C8 > glass–C3 > glass–C1 > glass. X-ray photoelectron spectroscopy was used to determine the surface chemical composition of the glass plates before and following coating with the silane coupling agents and/or the PPy thin layer, respectively. The attenuation in intensity of the glass Na_{1 s} peak enabled the average thickness of the various organosilane overlayers to be estimated. Atomic force microscopy showed that the morphology of the organosilane overlayers was islandlike. The domains have a structure which depends upon the nature of the organosilane in question. Scanning electron microscope images showed that the morphology of the PPyCl thin films was homogeneous when coated onto glass–APS and glass–C8, but wrinkled at the surface of glass, glass–C1 and glass–C3 plates. Qualitative peel tests using 3M adhesive tape showed very good adhesion of PPyCl to the glass–APS substrate, whereas adhesion was fairly poor in the case of glass–PPy and PPy–alkylsilane–glass interfaces. The results of this multitechnique study suggest that hydrophobic interactions are important to obtain homogeneous and continuous thin PPy films, but Lewis acid–base interactions are the driving forces for strong and durable PPy–glass adhesion. Received: 3 January 2000/Accepted: 19 May 2000     

Long-Chain Alkane Dehydrogenation over Hierarchically Porous Ti-Doped Pt–Sn–K/TiO2–Al2O3 Catalysts

Kinetics and Catalysis - Hierarchically porous γ-Al2O3, TiO2–Al2O3 composite supports, and Pt–Sn–K/Al2O3 and Pt–Sn–K/TiO2–Al2O3 catalysts were prepared...