Detection of Vibrational Spectroscopic Biomarkers of the Effect of Gold Nanoparticles on Wheat Seedlings Using Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy

The aim of this study is to evaluate the biochemical changes in the leaves of wheat seedlings exposed to gold nanoparticles (AuNPs) nondestructively and rapidly using attenuated total reflectance Fourier transform infrared spectroscopy and laser-induced fluorescence. The 18?nm size gold nanoparticles are synthesized by citrate reduction. For analyzing the effect of gold nanoparticles on wheat seedlings, the treatment of gold nanoparticles was applied to the seedlings through roots and following the spectroscopic measurement of biochemical signatures. The laser-induced fluorescence measurement has been performed to access the effect of gold nanoparticles on the chlorophyll concentration of wheat seedlings. The decrease in the fluorescence intensity and the fluorescence intensity ratio on the treatment of gold nanoparticles indicates increase in the concentration of chlorophyll in the leaves of wheat seedlings. The attenuated total reflectance Fourier transform infrarred spectroscopy in combination with principal component analysis has been used to visualize the biochemical changes in the cellulose, hemicellulose, pectin, lignin, amino acids, proteins, and lipid of the leaves of wheat seedlings by recording infrared spectra in the region from 4000 to 400?cm^?1. Principal component analysis applied to the preprocessed infrared data clearly distinguishes the spectral variability between control and gold nanoparticle treated seedlings. The study shows that exposure of gold nanoparticles increases the concentrations of cellulose, hemicelluloses, pectin, and lignin in the leaves of wheat seedlings. The increase in these chemicals indicates the modulation of cell walls of the wheat seedlings by the gold nanoparticle treatment. The exposure to gold nanoparticles also enhances the expression of lipid and proteins in the leaves of wheat seedlings.     

Non-invasive Monitoring of Biochemical Response of Wheat Seedlings Toward Titanium Dioxide Nanoparticles Treatment Using Attenuated Total Reflectance Fourier Transform Infrared and Laser Induced Fluorescence Spectroscopy

Widespread commercial application of titanium dioxide nanoparticles leads to their dispersion in the environment and inevitable interaction with living organisms. Their presence necessitates the monitoring of nanoparticle interactions with plants using advanced techniques that are capable of noninvasively and sensitively estimating the changes involved in the biochemical profile. The current study aims to investigate the effects of titanium dioxide nanoparticles on biochemicals of wheat leaves using label free, nondestructive, rapid, sensitive, and advanced spectroscopic probes: laser induced fluorescence and attenuated total reflectance Fourier transform infrared spectroscopy coupled with multivariate analysis. The fluorescence and infrared spectra of control and titanium dioxide nanoparticle treated wheat leaves were acquired in the region from 400 to 800?nm and 4000 to 485?cm^?1. The treatment of titanium dioxide nanoparticles decreases the chlorophyll content and the concentrations of cellulose, hemicellulose, xyloglucans, pectin, and lignin indicating interferences in the biosynthesis and structure of cell walls of the wheat leaves. The level of amide I, carbonyl, and methylene groups also increases following the treatment of titanium dioxide nanoparticles indicating lipid and protein peroxidation and the accumulation of carbonyl compounds. The changes in the integrated area ratios of the amide II/amide I, carbonyl/methyl, and methylene/amide II bands demonstrate disorder in the membrane integrity. This study establishes the efficiency of noninvasive, label-free, and rapid protocols based on attenuated total reflectance Fourier transform infrared and laser induced fluorescence to monitor the interactions of nanoparticles with plants at early stage of plant growth before visual signs of toxicity appear.     

Nondestructive and Rapid Probing of Biochemical Response of Arsenic Stress on the Leaves of Wheat Seedlings Using Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy

The goal of the current study is to characterize the changes in the biochemical composition of the leaves of wheat seedlings stressed by arsenic at concentrations of 0.2, 0.3, 0.4, and 0.5?mM using laser induced chlorophyll fluorescence and attenuated total reflectance Fourier transform infrared spectroscopy. The chlorophyll fluorescence spectra of the leaves of control and arsenic treated wheat seedlings showed increase in the intensity and intensity ratios of chlorophyll fluorescence bands indicating decrease in the photosynthesis performance and chlorophyll content of the leaves of wheat seedlings treated with arsenic. The infrared spectra of the leaves of control and arsenic treated wheat seedlings were obtained from 4000 to 485?cm^?1 at a resolution of 4?cm^?1. Multivariate principle component analysis of the preprocessed spectra suggest significant biochemical discrimination between the control and arsenic treated seedlings. Arsenic treatment decreased the concentration of cellulose while increasing the pectin, hemicellulose, xyloglucan, and lignin levels in the wheat seedling leaves. The exposure to arsenic also increased the spectral signatures of α-helix, β-sheet, amino acids, glutathione, lipids, and carboxyl compounds. These changes in the biochemicals indicate their physiological roles in mediating arsenic stress in wheat seedlings. The study also demonstrates the applicability of spectroscopic techniques for the non-invasive and rapid monitoring of the metabolism and physiology of the vegetation stressed by metals and metalloids before visual signs of toxicity appear.     

Non-destructive Phenotyping of Chili Pepper Ripening Using Spectroscopic Probes: A Potential Approach for Shelf-Life Measurement

This study explores the application of spectroscopic techniques (laser induced fluorescence, Raman and attenuated total reflectance Fourier transform infrared) coupled with principal component analysis for the nondestructive, extraction free and rapid evaluation of biochemical changes associated with ripening of chili peppers at four stages (mature, pre-ripe, ripe and post-ripe). The analysis of the fluorescence spectra of the exocarp of chili pepper shows a decrease in the intensity of chlorophyll bands at 685 and 735?nm and an increase in the intensity of carotenoid fluorescence bands at 490–500?nm and 565–580?nm with progress in the ripening stages. These changes are regarded to be significant phenotypic markers for the ripening of chili peppers. The observed changes in the position of carotenoid bands in Raman spectra at 1004, 1156, 1188, and 1524?cm^?1 with increase in their intensity indicating the accumulation of carotenoids and change in the carotenoid composition from β-carotene in the mature chilis to capsanthin in the ripe chilis. In addition, the infrared spectra show changes in the carbohydrates, amide II, amide I and cutin at various stages of ripening. Also, the variation in the position of pectin bands indicates change in its molecular mass with decreasing content. The determined spectral signatures can be used as biomolecular index for effective monitoring of the ripening of chili peppers. The commercial application of noninvasive spectroscopic probes will be advantageous for the phenotyping of economically important plant parts, screening, grading, shelf life estimation and quality standardization.     

Performance of Pleurotus ostreatus Mushrooms and Spent Substrate for the Biosorption of Cd(II) From Aqueous Solution

The capacities of Pleurotus ostreatus mushroom and spent substrate were evaluated for the biosorption of cadmium (II) from aqueous solution in order to select the most efficient material for bioremediation. The optimum sorption conditions were optimized, including the pH of the aqueous solution, contact time, biomass dosage, initial metal concentration, and temperature. The sorption of cadmium on both biosorbents was also evaluated by several kinetic, equilibrium, and thermodynamic models. The possible heavy metal biosorption mechanisms were evaluated through point of zero charge (pH_pzc), Fourier-transform infrared (FTIR) spectroscopy and scanning electron microscopy coupled with energy dispersive X-ray microanalysis (SEM-EDX). Based on the results of column studies, the effectiveness of the P. ostreatus spent substrate was confirmed as a biosorbent for Cd(II) removal from aqueous solutions.     

Recent advances in the use of graphene-family nanoadsorbents for removal of toxic pollutants from wastewater

Adsorption technology is widely considered as the most promising and robust method of purifying water at low cost and with high-efficiency. Carbon-based materials have been extensively explored for adsorption applications because of their good chemical stability, structural diversity, low density, and suitability for large scale production. Graphene – a single atomic layer of graphite – is the newest member in the family of carbon allotropes and has emerged as the “celeb” material of the 21st century. Since its discovery in 2004 by Novoselov, Geim and co-workers, graphene has attracted increased attention in a wide range of applications due to its unprecedented electrical, mechanical, thermal, optical and transport properties. Graphene's infinitely high surface-to-volume ratio has resulted in a large number of investigations to study its application as a potential adsorbent for water purification. More recently, other graphene related materials such as graphene oxide, reduced graphene oxide, and few-layered graphene oxide sheets, as well as nanocomposites of graphene materials have also emerged as a promising group of adsorbent for the removal of various environmental pollutants from waste effluents. In this review article, we present a synthesis of the current knowledge available on this broad and versatile family of graphene nanomaterials for removal of dyes, potentially toxic elements, phenolic compounds and other organic chemicals from aquatic systems. The challenges involved in the development of these novel nanoadsorbents for decontamination of wastewaters have also been examined to help identify future directions for this emerging field to continue to grow.     

Nanoparticles: Properties,applications and toxicities

This review is provided a detailed overview of the synthesis, properties and applications of nanoparticles (NPs) exist in different forms. NPs are tiny materials having size ranges from 1 to 100 nm. They can be classified into different classes based on their properties, shapes or sizes. The different groups include fullerenes, metal NPs, ceramic NPs, and polymeric NPs. NPs possess unique physical and chemical properties due to their high surface area and nanoscale size. Their optical properties are reported to be dependent on the size, which imparts different colors due to absorption in the visible region. Their reactivity, toughness and other properties are also dependent on their unique size, shape and structure. Due to these characteristics, they are suitable candidates for various commercial and domestic applications, which include catalysis, imaging, medical applications, energy-based research, and environmental applications. Heavy metal NPs of lead, mercury and tin are reported to be so rigid and stable that their degradation is not easily achievable, which can lead to many environmental toxicities.     

Analysis of questioned documents: A review

During the last years (2000–2014), many publications concerning the forensic analysis of questioned documents have been published, and new techniques and methodologies are nowadays employed to overcome forensic caseworks. This article reviews a comprehensive collection of the works focused on this issue, including dating studies, the analysis of inks from pens and printers, the analysis of paper, the analysis of other samples related to questioned documents and studies on intersecting lines. These sections highlight the most relevant analytical studies by a wide range of analytical techniques. Separation and spectrometric techniques are critically discussed and compared, emphasizing the advantages and disadvantages of each one. Finally, concluding remarks on the research published are included.     

Characterization of carbon nanotubes and analytical methods for their determination in environmental and biological samples: A review

In the present paper, a critical overview of the most commonly used techniques for the characterization and the determination of carbon nanotubes (CNTs) is given on the basis of 170 references (2000–2014). The analytical techniques used for CNT characterization (including microscopic and diffraction, spectroscopic, thermal and separation techniques) are classified, described, and illustrated with applied examples. Furthermore, the performance of sampling procedures as well as the available methods for the determination of CNTs in real biological and environmental samples are reviewed and discussed according to their analytical characteristics. In addition, future trends and perspectives in this field of work are critically presented.     

Speciation and detection of arsenic in aqueous samples: A review of recent progress in non-atomic spectrometric methods

Inorganic arsenic (As) displays extreme toxicity and is a class A human carcinogen. It is of interest to both analytical chemists and environmental scientists. Facile and sensitive determination of As and knowledge of the speciation of forms of As in aqueous samples are vitally important. Nearly every nation has relevant official regulations on permissible limits of drinking water As content. The size of the literature on As is therefore formidable. The heart of this review consists of two tables: one is a compilation of principal official documents and major review articles, including the toxicology and chemistry of As. This includes comprehensive official compendia on As speciation, sample treatment, recommended procedures for the determination of As in specific sample matrices with specific analytical instrument(s), procedures for multi-element (including As) speciation and analysis, and prior comprehensive reviews on arsenic analysis. The second table focuses on the recent literature (2005–2013, the coverage for 2013 is incomplete) on As measurement in aqueous matrices. Recent As speciation and analysis methods based on spectrometric and electrochemical methods, inductively coupled plasma-mass spectrometry, neutron activation analysis and biosensors are summarized. We have deliberately excluded atomic optical spectrometric techniques (atomic absorption, atomic fluorescence, inductively coupled plasma-optical emission spectrometry) not because they are not important (in fact the majority of arsenic determinations are possibly carried out by one of these techniques) but because these methods are sufficiently mature and little meaningful innovation has been made beyond what is in the officially prescribed compendia (which are included) and recent reviews are available.