Abstract: 1H longitudinal relaxation time profiles (T1) at different proton Larmor frequencies were registered for a solid-state plant tissue by using fast field cycling (FFC) nuclear magnetic resonance (NMR) spectroscopy. T1 distributions were obtained and the curves deconvoluted in order to differentiate among the different T1 components. Among the components, two were assigned to hydrophobic (e.g., fatty acid) and hydrophilic (e.g., saccharide) molecular systems, whereas the others were attributed to bulk and bound water. This paper shows for the first time solid-state FFC-NMR spectroscopy applied to plant tissue and reveals that relaxometry is a very promising technique for studying plant systems.

Abstract: Inductively coupled plasma–optical emission spectrometry was used to determine copper, iron, and zinc in both whole Crayfish and tail meat of crayfish from selected areas in southwestern Louisiana. Also included was a comparison between male and female crayfish. Results showed no significant difference between male and female crayfish and individuals from different sites. Iron was approximately four times greater in concentration for whole crayfish compared with tail meat.

Abstract: The state of the art of green spectroscopy, as a sustainable and friendly alternative to the classical spectrometric methods of analysis, has been established from the evaluation of the scientific literature published about this topic in the frame of the so-called Green Chemistry paradigm. Special attention has been paid to the fact that keywords like Green Analytical Chemistry, environmentally friendly, or clean analytical method or sustainable analytical chemistry are far from being commonly used in analytical studies. In spite of this fact there are numerous studies that provide direct analytical methodologies, or a reduction of reagents consumption or waste generation, the recycling of used solvents, or the replacement of toxic compounds by non-toxic or, at least, less toxic ones. So, additional efforts must be made to engage the scientific community in the practice of making the work safer and more sustainable in the analytical laboratories.

Abstract: The aim of this study was to investigate the changes of Fourier transform infrared (FT-IR) spectra of rat liver and spleen tissues from time zero to 144 h postmortem. The absorbance (Ax represents the infrared absorbance at wavenumber x cm−1) ratios of major absorbance bands were examined. A 3303/A 2925, A 1647/A 1541 (liver), A 1238/A 1338, A 1153/A 1338 (liver), A 1080/A 1338, and A 1030–1050/A 1338 (liver) showed a decrease postmortem, whereas the A 1396/A 1456 ratio (spleen) showed an increase. Furthermore, these absorbance ratios showed a strong linear relationship with increasing time postmortem, and the A 1238/A 1338 ratio of spleen offered a stronger correlation (R 2 = 0.88) than did the others. A new absorbance band appeared at 1120 cm−1 for the liver and spleen at 120 h postmortem and another new band appeared at 1170 cm−1 for the liver, but the existing absorbance band at 1170 cm−1 disappeared in the spleen. Our initial results demonstrate that the quantitative analysis of FT-IR spectr...

Abstract: This article reviews the work over the past few years on the photolysis of propionaldehyde, n-butyraldehyde, n-pentanal, n-hexanal, and n-heptanal in the 280–330 nm region, obtained by combining laser photolysis with cavity ring-down spectroscopy. Absorption cross-sections of these aldehydes were measured. The HCO radical was observed as a photodissociation product. The HCO quantum yield was determined as a function of photolysis wavelength, aldehyde pressure, and nitrogen buffer-gas pressure. A scheme to group aldehydes according to similarity in photochemistry was proposed.

Abstract: Since its creation, the Multisyringe Flow Injection Analysis (MSFIA) technique has proved to be a highly useful tool for the automation of sample pretreatment procedures prior to spectroscopic detection (UV-vis spectrophotometry, fluorescence, or chemiluminescence). This article reviews the recent applications of the MSFIA technique and how they have contributed to the Green Analytical Chemistry field. These contributions are mainly based on the development of multicommutated analytical methodologies for the minimization of the consumption of reagents, automation and miniaturization of solid phase extraction, reagent immobilization, or in the automation and miniaturization of the required pretreatments prior to separation techniques.

Abstract: The UV-Vis spectroscopic behavior of the solvatochromic dye 4-[(1-methyl-4(1H)-pyridinylidene)-ethylidene]-2,5-cyclohexadien-1-one (Brooker's merocyanine) was investigated in aqueous solution (pH 10.55) in the presence of increasing amounts of native (α- and β-) and modified (methyl-β- and hydroxypropyl-β-) cyclodextrins. The data obtained showed that a bathochromic shift occurs in the dye solution after the addition of the cyclodextrins, indicating that the probe is transferred to a low-polarity microenvironment with the addition of the cyclodextrin. Experimental data also suggest the occurrence of a 1:1 dye:cyclodextrin inclusion complex.

Abstract: Arsenic is a toxic heavy metal that occurs naturally in water, soil, and air. It is widespread in the environment as a consequence of both anthropogenic and natural processes. In the current study, an attempt has been made to analyze the arsenic-induced molecular changes in macromolecular components like proteins and lipids in the kidney tissues of edible fish Labeo rohita using Fourier transform infrared (FTIR) spectroscopy. The FTIR spectrum of kidney tissue is quite complex and contains several bands arising from the contribution of different functional groups. The detailed spectral analyses were performed in three distinct wave number regions, namely 3600–3050 cm−1, 3050–2800 cm−1, and 1800–800 cm−1. The current study shows that the kidney tissues are more vulnerable to arsenic intoxication. FTIR spectra reveal significant differences in both absorbance intensities and areas between control and arsenic-intoxicated kidney tissues; this result indicates that arsenic intoxication induces signifi...

Abstract: A sensitive, selective, and solvent-free method based on direct immersion solid-phase microextraction (DI-SPME) followed by gas chromatography with mass spectrometry (GC-MS) is proposed for the determination of trace amounts of famoxadone in wines, fruits, and vegetables. Parameters affecting the sample enrichment step, such as sample mass, ionic strength, adsorption and desorption times, and temperatures were carefully optimized. A polar 85 µm polyacrylate fiber was found to be suitable for extraction at 60°C in 20 min under continuous stirring. Desorption was carried out at 270°C for 5 min. Undiluted wine samples and diluted extracts obtained from the solid samples submitted to an ultrasound treatment in the presence of ethanol were quantified against external aqueous standards prepared in 12% ethanol (v/v). Under the optimized conditions, detection limits of 5 ng L−1 and 10 pg g−1 were obtained for liquid and solid samples, respectively. SPME-GC-MS analysis yielded good repeatability (RSD unde...

Abstract: The interaction of isoquercitrin and bovine serum albumin (BSA) was investigated by means of fluorescence spectroscopy (FS), resonance light scattering spectroscopy (RLS), and ultraviolet spectroscopy (UV). The apparent binding constants (K a) between isoquercitrin and BSA were 5.37 × 105 L mol−1 (293.15 K) and 2.34 × 105 L mol−1 (303.15 K), and the binding site values (n) were 1.18 ± 0.03. According to the Forster theory of non-radiation energy transfer, the binding distances (r) between isoquercitrin and BSA were 1.94 and 1.95 nm at 293.15 K and 303.15 K, respectively. The experimental results showed that the isoquercitrin could be inserted into the BSA, quenching the inner fluorescence by forming the isoquercitrin–BSA complex. The addition of increasing isoquercitrin to BSA solution leads to the gradual enhancement in RLS intensity, exhibiting the formation of the aggregate in solution. It was found that both static quenching and non-radiation energy transfer were the main reasons for the fluo...

Abstract: Sequential injection analysis (SIA) is proposed for managing microvolumes of sample and arsenic species solutions for speciation analysis by capillary electrophoresis focusing on the reduction of hazardous waste residues. An electronically controlled hydrodynamic injector was projected to introduce microvolumes of solutions prepared by SIA into the CE capillary with precision better than 2%. The determination of arsenite, arsenate, monomethylarsonic acid, dimethylarsinic acid, and arsenobetaine was performed from 50 µL volumes of lyophilized urine and extract of shrimp with the system hyphenated to inductively coupled plasma mass spectrometry (CE–ICP–SFMS).

Abstract: The demand for lactic acid as a raw material for the chemical industry is on the rise. Various lactic acid bacteria (LAB) have been tested for the fermentation of sugar-cane juice and molasses into lactic acid. Industrially, the most commonly used producer strains are from the Lactobacillus genus. We report here on the fermentation of sugar-cane juice and syrup into L-lactic acid using Lactobacillus delbrueckii subsp delbrueckii (NCIM 2365). We present a reliable method to quantitatively assess the amount of L-lactic acid produced during fermentation using 1H NMR spectroscopy. This analytical method offers various advantages over existing ones and can be extended to the on-line monitoring of fermentation of sugars into lactic acid in industry.

Abstract: The solvatochromic behavior of the title phenolate 1 was described and interpreted by means of theoretical calculations employing the PCM model and a TD-DFT method. The cationic halochromism of 1 was studied in DMSO and in ethanol solutions of LiClO4 and interpreted by a simple model that reproduced the variation of the charge-transfer transition energy of 1 with the cation concentration in solution.

Abstract: In this work, the quantitative structure–properties relationship (QSPR) was applied to modeling and predicting the 29Si-NMR chemical shifts of a series of silicate species (on Q2 sites). The descriptors that were selected by stepwise multiple linear regression technique were square of alpha polarizability, Moran autocorrelation–lag3/unweighted by atomic Sanderson electronegativities, square of asphericity, and topological path/walk 2-Randic shape index. These descriptors could encode electronic, geometric, and topological characteristics that affect the chemical shifts of the molecules of interest. The results obtained using the multiple linear regression (MLR) model were comparable with the experimental values. The cross-validation test was also performed to evaluate the prediction power of the MLR model obtained. The q2 and PRESS of this model are 0.976 and 0.44761, respectively, revealing the credibility of the model.

Abstract: A lanthanum(III) complex of catechin has been synthesized and characterized by elemental analysis, molar conductance, UV-Vis spectra, infrared spectra, thermal analysis, and 1H NMR. The complex behaves as a nonelectrolyte in methanol solvent. The spectral and thermal properties of the complex are examined. A thermogravimetric (TGA) study showed the hydrated nature of the complex. 1H NMR spectra of the lanthanum and the catechin (CT) ligands measured in CD3OD-d4 also show metal ligand coordination. The lanthanum–catechin complex shows bright luminescence in methanol solution. The interaction of the complex with calf thymus DNA has been investigated by absorption and emission spectroscopic measurements. Experimental spectral results suggest CT–DNA binding with catechin complex via an intercalative mode.

Abstract: Leaf oils of Cymbopogon flexuosus and Cymbopogon tortilis were submitted to combined analysis by CG(retention indices), Gas Chromatography Mass Spectrometry (GC-MS), and 13C Nuclear Magnetic Resonance (NMR). The composition was dominated by geranial (39.2% and 32.0%) and neral (24.1% and 19.1%). Cis- and trans-7-hydroxy-3,7-dimethyl-3,6-oxyoctanal (synonym: cis- and trans-tetrahydro-5-(1-hydroxy-1-methylethyl)-2-methyl-2-furanacetaldehyde) were identified by 13C NMR by comparison with literature data.

Abstract: On-line atom trapping inside a nickel flame furnace using chemical vapor generation for sample introduction was proposed for the determination of trace cadmium by flame atomic absorption spectrometry (AAS). Cadmium volatile species was generated upon reaction with potassium borohydride and then flushed into a flame furnace for on-line trapping by a flow of nitrogen carrier gas. The middle part of the flame furnace, where the carrier gas impacts, is cooled by the gas flow, and this provides a fine strategy for on-line atom trapping for the purpose of preconcentration. A stainless steel plate is put on the top of the flame burner in the middle to form a flame-free zone, which also greatly lowers the temperature of the flame furnace and facilitates the atom-trapping process. Due to the introduction of chemical vapor generation, matrix effect was greatly alleviated compared with direct pneumatic nebulization for on-line atom trapping in flame furnace AAS. With trapping time of 35 s, the current appro...

Abstract: Co(II), Ni(II), Cu(II), Cd(II), and Fe(II) complexes with Schiff base derived from 2-amino-5-(2-amino-1,3,4-thiadiazolyl)-1,3,4-thiadiazole (1) and salicylaldehyde have been prepared. The ligand an...

Abstract: Silicon-29 NMR spectroscopy was used to characterize aqueous and alcoholic alkaline solutions of tri-butylmethyl ammonium (TBMA) silicates. The effect of TBMA cation on the equilibrium of silicate oligomers in aqueous alkaline silicate solutions was investigated using 29Si NMR spectra. It was found that TBMA cation has a structure directing role and directs the silicate species to form minor amounts of silicate anion in the presence of high concentration of silicon. Silicon-29 NMR spectra of TBMA silicate solutions indicate that considerable changes occurred by changing the Si/TBMA ratio. The distribution of silicate species was affected by the presence of the alcohols, specifically methanol.

Abstract: A review of recent literature utilizing alternative sample pretreatment methods for solid environmental and biological materials analysis to assess total metals content by atomic spectrometry is provided. All the selected treatments coincide with all or some of the fundamentals of Green Chemistry policy such as prevention of waste generation; safer and less toxic solvents and reagents; and designs for energy efficiency. The review covers the classic slurry sampling technique, mainly, its current trends, as well as developments based on the use of diluted acids, chelating agents solutions, or even water for leaching (extraction) methods assisted by ultrasounds, microwave energy, or pressurization. In addition, the use of conventional or assisted enzymatic hydrolysis procedures is also discussed.

Abstract: The fluorescence quenching of solutes 3-[5′-methyl-3′-phenylindol-2′-yl]-s-triazolo [3,4-b] [1,3,4] thiadiazol-6(5H)-thione (MPITTT) and 3-phenyl-2,5-bis-[thiosemicarbazido] indole (PbisTI) by carbon tetrachloride (CCl4) in dioxane and acetonitrile mixtures has been studied at room temperature by steady-state fluorescence measurements. The positive deviation from linearity has been observed in the Stern–Volmer (S-V) plots for both fluorophores in different composition of mixed solvents even at moderate CCl4 concentration (0.10 mol dm−3). Various quenching parameters of the quenching processes have been determined using the extended S-V equation and have been found to be dependent on the solvent polarity. Further, with the use of the finite sink approximation model, it is concluded that the bimolecular quenching reactions are diffusion limited, and the distance parameter R′ and mutual diffusion coefficient D are estimated independently.

Abstract: The crystal structures of 5-benzyl-2-thiohydantoin (5-BTH) and 1-acetyl-5-benzyl-2-thiohydantoin (1-Ac-5-BTH) have been determined by X-ray diffraction. In the 5-BTH crystals, the enantiomeric (R)- and (S)-5-BTH molecules are connected to form cyclic dimers via the hydrogen bonds of the thioamide and the amide moieties. On the other hand, the intermolecular hydrogen bonds in 1-Ac-5-BTH crystals form an infinite chain. These differences in the hydrogen bond pattern are also discussed in the IR and Raman spectra. The ab initio molecular orbital calculations (Gaussian 03) with 6-31G(d,p) basis set were carried out for 5-BTH and 1-Ac-5-BTH to get the preferred conformation.

Abstract: In situ Fourier transform IR spectroscopy was a useful tool in monitoring the pH-dependent and two-step oximation of methyl ethyl ketone and benzaldehyde in a liquid–liquid two-phase system, one phase of which was water. Carrying out the oximations at pH 8, the oximation was complete within 45 min and the corresponding carbonyl compound–hydroxylamine adduct (2) could be detected as an intermediate, but at pH 10, the corresponding oxime (3) was formed faster, practically without the appearance of the intermediate. At pH ∼ 2.5 using methyl ethyl ketone, the protonated form of the corresponding oxime (3'a) developed gradually without the transient appearance of the intermediate (2). pH dependence of the 3a → 3'a and 3'a → 3a interconversions were studied in separate experiments.

Abstract: A simple, convenient, sensitive, and environmentally friendly analysis method for carbamate pesticide residues in vegetable samples was proposed by using electrokinetic flow analysis (EFA) with on-line hollow fiber liquid–liquid–liquid microextraction (LLLME) and ultraviolet spectrophotometry (UV). On-line LLLME conditions were investigated, including organic solvents, flow rate of sample loading, extraction times and sample volume, and so on. With dodecanol phase immobilized on the hollow fiber, the on-line LLLME unit could be operated for 150 hr. In each regeneration of dodecanol phase on the hollow fiber, the consumption of dodecanol was 50 µL, namely., the consumption rate was 0.33 µL h−1. By introducing 5.0 mL sample solution, the analytical time was 22 min and the enrichment factor of carbaryl achieved 300. The linear calibration range was from 0.0033 to 1.0 µg mL−1 carbaryl, which was used as a converted concentration for total carbamate pesticides. The relative standard deviation (R.S.D.)...

Abstract: In the current work a Green Analytical Chemistry (GAC) procedure for photometric determination of orthophosphate in river water at µg L−1 concentration level is described. The flow system module and the LED-based photometer were assembled together to constitute a compact unit in order to allow that a flow cell with optical path-length of 100 mm was coupled to them. The photometric procedure based on the molybdenum blue method was implemented employing the multicommuted flow injection analysis approach, which provided facilities to allow reduction of reagent consumption and as well as waste generation. Aiming to prove the usefulness of the system, orthophosphate in river and tap waters was determined. Accuracy was ascertained by spiking samples with orthophosphate solution yielding recoveries ranging from 96% up to 107%. Other profitable features such as a wide linear response range between 10 to 800 µg L−1 ; a detection limit (3σ criterion) of 2.4 µg L−1 ; a relative standard deviation (n = 7) of...

Abstract: In this short letter, we report a compact spectrophotometer consisting of a liquid core waveguide as the optical cell and a handheld charge coupled device spectrometer as the detector. This instrumentation features portability, ultrahigh sensitivity, simultaneous multicomponent detection, and minimal analyte solution. Its ultrahigh sensitivity permits the measurement of Cr(III) without coloration with any reagents. Therefore, a simple, fast, cost-effective, and green analytical method was developed for the ultrasensitive and simultaneous speciation analysis of Cr(III) and Cr(VI) in water samples, with the limits of detection down to the ppb level.

Abstract: The technique of micro-Raman spectroscopy has the advantages of being nondestructive, high speed, high accuracy and also can be used for finite-precision analysis in combination with microscopy. In this paper, bleached and filled jadeite-jade and filled ruby were selected as the analysis objects, and then micro-Raman spectroscopy in combination with XRF and IR was carried out for detection and analyses. There were many microcracks observed in the micrograph of jadeite-jade, which is the result of bleaching with strong acid, and it was proved that these cracks were filled with epoxy resin by the diagnostic Raman shifts near 777, 1123, 1611, 2930, and 3065 cm−1. Many cracks and white floccules were observed in the micrograph of filled ruby; This was the result of filling with lead glass and organic material. In addition, the broad and strong Raman shift near 1563 cm−1 was attributed to lead glass, and Raman shifts near 2331, 2874, and 3285 cm−1 were attributed to organic filler. This analysis metho...

Abstract: The vacuum ultraviolet (VUV) absorption spectrum of difluoromethane (CH2F2) was studied using synchrotron radiation from the storage ring Indus-1, Indore, India. Spectra were recorded in the spectral region 1050–1500 A (∼8.3–11.8 eV) at a resolution of 1.5 A. Three absorption band systems were observed in this region. Overall features observed are in good agreement with previously published work. Some discrepancies in assignments of the observed vibronic bands carried out by previous workers have been resolved. The observed bands have been classified in terms of Rydberg series.

Abstract: Spectroscopy and flow methodologies are an interesting and fruitful marriage in the field of Green Analytical Chemistry (GAC). Automation, immobilization of analyte, reagent(s), reaction product, or catalyst on active solid surfaces and miniaturization are highlighted as alternatives for waste decrease. Flow-Through Solid-Phase Spectroscopy (FSPS) can be envisaged as a variant of the use of immobilized reagents. It is implemented by placing the solid support inside the flow cell in order to perform the analyte (or its reaction product) retention and detection simultaneously. FSPS is an interesting spectroscopy approach that offers simple and rapid procedures that fulfil satisfactorily the requirements demanded by GAC. This article is focused on the contribution of FSPS methodologies to the GAC concept. The different strategies and types of FSPS developed will be presented and discussed in detail under the Green Spectroscopy point of view.