Standard Wet Chemical Methods Research Articles

Formulation and Evaluation of Starch Phosphate-Based Cream Derived from Manihot esculentus

AbstractStarch is an important excipient employed in the pharmaceutical industry but irrespective of its source, the native starch is undesirable for many applications because of its inability to withstand processing conditions and hence needs its modification to achieve the desired properties. This study aimed to synthesize starch phosphate through the modification of starch obtained from Manihot esculentus, and then explore its potential in the preparation of cream formulations. In the present study, the starch was extracted from M. esculentus (cassava), then phosphorylated by reacting with varied concentrations of disodium hydrogen phosphate, anhydrous (Na2HPO4, 0.05, 0.1, and 0.2 mol/dm3) under pH 6. A standard wet chemistry method was used for the determination of the degree of substitution by phosphate (DSp) of modified starch, and Fourier transform infrared (FTIR) spectra were used for structure identification. The starch phosphate obtained was employed to develop a cream formulation. The physicochemical properties of the formulation were further evaluated. Calamine cream BP was utilized as a control. Our result indicated that a higher concentration of Na2HPO4 favors a higher DSp (0.047). FTIR spectra of the modified starch suggested a new peak at 1,090 cm−1 (P-OR). The cream formulated with a high DSp of starch phosphate demonstrated good physicochemical properties with spreadability (7.84–8.65 gcm/s), pH (6.5–7.0), viscosity (267–296 cp), extrudability (2.05–2.62%) and physical stability, and were smooth, opaque, greasy, homogeneous, and easily removed on washing with water. Statistical analysis showed that there was no significant difference between the starch phosphate-based cream and the control, but a significant difference between the starch phosphate-based cream and a native starch-based cream. Given the above, starch phosphate with a high DSp can be prepared from M. esculentus starch and utilized as a promising emulsifying agent in cream formulation due to its being more widely available, more stable, and cost-effective.

Preparation and Characterization of Silver Nanoparticles by Pulsed Laser Ablation and Investigation of their Effect on Bacteria

Synthesis of silver nanoparticles (AgNP) by pulsed liquid laser ablation (PLAL) produces AgNPs that are better suited for biological applications compared to those prepared by standard wet-chemical methods. These were mainly achieved by water ablation with pulse widths in the nanosecond range. In the case of surface NP activation, we previously detected a strong surface-enhanced Raman scattering (SERS) signal from such AgNPs. To do this, we dilute Colloid slightly with LiCl. These surface alterations may have an effect on the NPs' capability to combat bacteria. every time, AgNPs with a median diameter of under ten nm were created., that has been incontestible in alternative studies to be the optimum size for germicidal activity.. Furthermore, minimum restrictive concentration (MIC) values for LiCl-modified AgNPs fell inside a slender vary of 1.1-3.8 g/mL, creating them the foremost efficient. This result's believed to be explained by the metal surface's enhanced surface reactivity, which is brought on by the existence of charged active sites.

Sources and concentrations of acidic constituents in the ambient air of Saudi Arabia

Air pollution has given great interest because of its wide adverse effects on the human health and all components of the ecosystem. In developing countries, research concerning assessment of acidic constituents of the ambient air and its effects is still lacking, particularly in the Arab ones. The objective of this study was to assess levels of acidic constituents of the ambient air in Saudi Arabia through selection of Dammam City as a case study. This study presents a comprehensive set of three successive academic years of data (2016–2019). Levels of PM10, SO2, and NO2 were continuously measured for 24 h/day. Concentrations of Cl−, SO42−, and NO3− and fly ash were determined by standard wet chemical methods. The mean concentrations of PM10 (177.4 ± 52.5 μg/m3) exceeded all the local and international standards, where levels of SO2 (17.5 ± 6.2 μg/m3) and NO2 (101.1 ± 27.3 μg/m3) were lower than their AQGs. The sum of the Cl−, SO42−, and NO3− constituted 29.2% of the PM10 concentration, while the fly ash constituted 55.1%. Dammam atmosphere is greatly affected by the combustion sources of industry and traffic activity rather than the formation of secondary aerosols as the result of chemical transformation of acidic gases (NO2 and SO2). In addition, acidic constituents of the ambient air are not a considerable environmental problem in Dammam City and Kingdom of Saudi Arabia as general.

Preparation of Lignin Nanoparticles from Wood Waste for Wood Surface Treatment.

Lignin was isolated from wood wastes comprising Iroko sawdust (IR) and mixed sawdust from Iroko and Norway spruce (IRNS), furnished by a local wood houses producer. The respective acidolysis lignin fractions were structurally characterized using pyrolysis (Py)-GCMS, two-dimensional heteronuclear single quantum correlation nuclear magnetic resonance (2D HSQC NMR), Fourier-transform infrared FTIR and ultraviolet-visible (UV-VIS) spectroscopies, size exclusion chromatography, and standard wet-chemistry methods for Klason lignin and polysaccharides determination. The isolated lignin fractions were subsequently used for the preparation of lignin nanoparticles (LNPs) using a non-solvent method. LNPs were then used for wood surface treatment using a dip-coating technique. The coated wood samples were analyzed by colorimetry and scanning electron microscopy (SEM) before and after artificial weathering experiments in a UV chamber to investigate the UV protection potential of the LNPs coatings. Wood samples dip-coated with LNPs showed promising surface modifications resembling a sort of film of fused LNPs. Coatings made from IR-LNPs and IRNS-LNPs performed significantly better in artificial weathering experiments than uncoated reference samples.

TEMPO-oxidized O-acetyl galactoglucomannan oligomers: isolation and comprehensive structural elucidation

Hemicelluloses, the second most abundant polysaccharides right after cellulose, represent complex biopolymers whose structural features are not yet fully understood. Hence, the applicability of functionalized hemicellulose derivatives is still limited. Thus, the development of practical methods to reveal their structure is essential. Anionic, carboxylated GGM was prepared as the substrate, and their corresponding oligomers have been isolated and fully characterized for the first time in the present work. In order to accomplish this, each step has been optimized sequentially. Oxidized GGM was enzymatically digested, and the corresponding oligomers were isolated by preparative GPC. A toolset of wet chemistry and instrumental methods was used to characterize the isolated compounds in detail. Moreover, quantitative 13C-NMR combined with MALDI was demonstrated to deliver accurate analytical data compared to standard but time-consuming wet chemistry methods. The developed toolset is expected to be applicable to other plant polysaccharides and their derivatives as well.

Potential of near infrared spectroscopy to monitor variations in soluble sugars in Loblolly pine seedlings after cold acclimation

The freeze tolerance of seedlings can be affected by cold acclimation. This acclimation can in turn alter the seedlings absorbance spectra due to variation of soluble sugar content (SSC). If models developed from the absorbance at wavelengths in the near infrared reflectance (NIR) region could provide information concerning the variation in SSC, nursery managers could assess the freeze tolerance of each seedling before planting. The objective of this research was to investigate the potential to use NIR based analysis to study the variation of SSC in Loblolly pine (Pinus taeda L.) seedlings after cold acclimation. Seventy seedlings were frozen using different cold treatments and 10 seedlings were designated as controls. The standard wet chemistry method was employed to collect the original SSC data, including glucose, fructose and galactose. NIR spectroscopy was completed by using a NIR machine, with a range of 10,000–4000cm−1. The results were analyzed using partial least squares regression in an effort to determine the SSC in the leaves, stems and roots. Results showed that the freeze tolerance of seedlings increased after cold acclimation and was positively related to the presence of SSC. After cold acclimation, leaves had the most SSC, and the galactose content was more than that of glucose or fructose in seedlings. Based on the determination coefficient (R2) and the residual predictive deviation (RPD), the predicted results of NIR models were evaluated. The model for leaf galactose (R2=0.88 and RPD=2.17) was the most stable and accurate model. This paper demonstrates that NIR coupled with chemometric modeling can be a useful tool in the monitoring of SSC variation and this information could be useful in the prediction of freeze tolerance.

Application of near-infrared spectroscopy for estimation of non-structural carbohydrates in foliar samples of Eucalyptus globulus Labilladière.

Near-infrared reflectance spectroscopy (NIRS) is frequently used for the assessment of key nutrients of forage or crops but remains underused in ecological and physiological studies, especially to quantify non-structural carbohydrates. The aim of this study was to develop calibration models to assess the content in soluble sugars (fructose, glucose, sucrose) and starch in foliar material of Eucalyptus globulus. A partial least squares (PLS) regression was used on the sample spectral data and was compared to the contents measured using standard wet chemistry methods. The calibration models were validated using a completely independent set of samples. We used key indicators such as the ratio of prediction to deviation (RPD) and the range error ratio to give an assessment of the performance of the calibration models. Accurate calibration models were obtained for fructose and sucrose content (R2 > 0.85, root mean square error of prediction (RMSEP) of 0.95%–1.26% in the validation models), followed by sucrose and total soluble sugar content (R2 ~ 0.70 and RMSEP > 2.3%). In comparison to the others, calibration of the starch model performed very poorly with RPD = 1.70. This study establishes the ability of the NIRS calibration model to infer soluble sugar content in foliar samples of E. globulus in a rapid and cost-effective way. We suggest a complete redevelopment of the starch analysis using more specific quantification such as an HPLC-based technique to reach higher performance in the starch model. Overall, NIRS could serve as a high-throughput phenotyping tool to study plant response to stress factors.

Application of infrared technique in soil properties’ characterization in South Kivu province of DR Congo

Understanding soil properties is an essential pre-requisite for sustainable land management. Assessment of soil properties has long been done through conventional laboratory analysis, which is costly and time consuming. Therefore, there is a need to develop alternative cheaper and faster techniques for soil analysis. In recent years, special attention has been given to Infrared Reflectance Spectroscopy and chemometrics. Near Infrared Reflectance (NIR) and mid-infrared (MIR) spectroscopy techniques are rapid, convenient and simple non-destructive techniques for quantifying several soil properties. This study aims to characterized soil based on based on infrared spectroscopy. This method were to predict soil pH, soil organic C, total N, exchangeable Al, Ca, Mg, and K, CEC and soil texture for soil samples collected in Sud-Kivu province, Democratic Republic of Congo. A total of 530 composite soil samples were taken from two locations (Burhale and Luhihi) at two depths (0-20 and 20- 40 cm) using a spatially-stratified random sampling design within an area of 100 km2. After minimal sample preparation, the MIR spectrum of a soil takes about two minutes for the analyses. Ddifferences in characteristics were evaluated between the two locations, land use (cultivated vs. non-agricultural land) and soil depth. A random subset of the samples (10%) were analyzed using standard wet chemistry methods, and calibration models developed using MIR data to estimate soil properties for the full soil sample set. Partial least squares regression (PLS) method gave acceptable coefficients of determination between 0.71 and 0.93 for all parameters hence good prediction. Though IR is cheap for analyzing soil properties it requires high investment at the beginning. There is therefore need of technical and material support to make this technology useful in developing countries.

Surface plasmon resonance-induced photoactivation of gold nanoparticles as mitochondria-targeted therapeutic agents for pancreatic cancer

Background: Noble metal nanoparticles such as gold nanoparticles can strongly absorb light in the visible region by inducing coherent collective oscillation of conduction band electrons in strong resonance with visible frequencies of light. This phenomenon is frequently termed as surface plasmon resonance (SPR).Objectives: The main objective was to study the effects of laser photoactivated gold nanoparticles (by means of SPR) on human pancreatic cancer cells.Results: Gold nanoparticles obtained using standard wet chemical methods (with sodium borohydride as a reducing agent) underwent photoexcitation using 2w 808 nm laser and further administered to 1.4E7 pancreatic cancer cell lines. Flow cytometry, transmission electron microscopy, phase contrast microscopy, quantitative proteomics and confocal microscopy combined with immunochemical staining were used to examine the interaction between photo excited gold nanoparticles and pancreatic cancer cells.Conclusion: The study shows that phonon–phonon interactions following laser photoexcitation of gold nanoparticles exhibit increased intracellular uptake, as well as mitochondrial swelling, closely followed by mitochondrial inner membrane permeabilization and depolarization. This unique data may represent a major step in mitochondria-targeted anticancer therapies using laser-activated gold nanoparticles.

Synthesis and characterisation of starch phosphates

Monostarch monophosphates with different phosphorus contents were prepared via reacting starch with a mixture of primary and secondary sodium phosphates under weak acidic conditions in a semi-dry process. For a structural characterisation of starch phosphates 31P NMR and FT Raman spectra were recorded. The degrees of substitution (DS P) of modified starch were determined using a standard wet chemistry method. By recording the FT Raman spectra of starch phosphates a characteristic band at ∼975 cm −1 was found whose intensity depends on the degree of phosphorylation of starch. The integrated areas of this C–O–P stretching vibration were plotted versus the degree of substitution DS P of starch phosphates obtained from standard photometric method. A strong linear correlation was derived which is suitable to determine the level of phosphorylation of starch phosphates with unknown DS P value by Raman spectroscopy as a rapid and non-destructive method.

In vitro toxicity studies of polymer-coated gold nanorods

We evaluated cellular responses to polymer-treated gold nanorods, which were synthesizedusing the standard wet-chemistry method that utilizes hexadecyltrimethylammoniumbromide (CTAB). The nanorod dispersions were coated with either polystyrene sulfonate(PSS) or polyethylene glycol (PEG). Two sizes of nanorods were tested, with opticalresponses peaking at 628 and 773 nm. The cells were from mammary adenocarcinoma(SKBR3), Chinese Hamster Ovary (CHO), mouse myoblast (C2C12) and HumanLeukemia (HL60) cell lines. Their mitochondrial function following exposure to thenanorods were assessed using the MTS assay. We found PEGylated particlesto have superior biocompatibility compared with PSS-coated nanorods, whichshowed substantial cytotoxicity. Electron microscopy showed no cellular uptake ofPEGylated particles compared with their PSS counterparts. PEGylated gold nanorodsalso exhibited better dispersion stability in the presence of cell growth medium;PSS-coated rods tended to flocculate or cluster. In the case of the PSS particles,toxicity correlated with surface area across the two sizes of nanorods studied.

Rapid Assessment of Lignin Content and Structure in Switchgrass (Panicum virgatum L.) Grown Under Different Environmental Conditions

Switchgrass (Panicum virgatum L.) is a candidate feedstock in bioenergy, and plant breeding and molecular genetic strategies are being used to improve germplasm. In order to assess these subsequent modifications, baseline biomass compositional data are needed in a relevant variety of environments. In this study, switchgrass cv. Alamo was grown in the field, greenhouse, and growth chamber and harvested into individual leaf and stem tissue components. These components were analyzed with pyrolysis vapor analysis using molecular beam mass spectrometry, Fourier transform infrared, and standard wet chemistry methods to characterize and compare the composition among the different growth environments. The details of lignin content, S/G ratios, and degree of cross-linked lignin are discussed. Multivariate approaches such as projection to latent structures regression found a very strong correlation between the lignin content obtained by standard wet chemistry methods and the two high throughput techniques employed to rapidly assess lignin in potential switchgrass candidates. The models were tested on unknown samples and verified by wet chemistry. The similar lignin content found by the two methods shows that both approaches are capable of determining lignin content in biomass in a matter of minutes.

Improved algorithm for the computation of nitrate concentrations in seawater using an in situ ultraviolet spectrophotometer

Improvements in the data processing algorithm and calibration procedures have greatly increased the accuracy of nitrate measurements using an in situ ultraviolet spectrophotometer (ISUS). Two major changes in the algorithm involve application of a temperature‐dependent correction to the bromide spectrum and then using the observed temperature and salinity to subtract the bromide component before fitting nitrate. By reducing the degrees of freedom in calculating nitrate concentrations, the accuracy of the ISUS instrument is substantially improved. The new algorithm was tested in environments ranging from the Southern Ocean to oligotrophic eastern Pacific seawater and found to be applicable at all temperatures and depths. The standard error of the estimate for regression between ISUS nitrate values and discrete samples measured by standard wet chemistry methods for the combined data set is reduced by greater than 2‐fold (1.4 down to 0.65 µM) using the new algorithm. This corresponds to a 5‐fold reduction in variance (2.0 down to 0.4 µM2). Although biofouling and calibration drift remain issues for any instrument deployed in situ for long periods of time, using the measured salinity and temperature to correct the ultraviolet spectra before the nitrate calculations will reduce the impacts of these confounding processes.

One-step growth of gold nanorods using a β-diketone reducing agent

The synthesis and characterisation of gold nanorods have been carried out by reduction of the gold salt HAuCl4. This has been done using a single reducing agent, acetylacetone, rather than the two reducing agents, sodium borohydride and ascorbic acid, normally required by standard wet chemistry methods of gold nanorod formation. Using this novel method, the nanorods were synthesised at several different pH values which were found to greatly affect both the rate at which the nanorods form and their physical dimensions. The concentrations of acetylacetone and silver nitrate used relative to the gold salt were found to alter the aspect ratio of the nanorods formed. Rods with an average length of 42 nm and an aspect ratio of 4.6 can be easily and reproducibly formed at pH 10 using this method. Nanorods formed under optimum conditions were investigated using TEM.

Raman spectroscopic determination of extent of O-esterification in acetylated soy protein isolates

Soy protein isolates were chemically modified with varying amounts of acetic anhydride, and the extent of O-esterification was determined by a standard wet chemistry method. Raman spectra of the modified soy proteins were obtained. A characteristic 1737 cm −1 CO vibrational band was observed and its intensity was dependent on the degree of O-esterification. The ratio of intensity of the 1737 cm −1 band to a 1003 cm −1 phenylalanine stretch band (used as an internal standard) was plotted against the extent of O-esterification determined chemically. A linear fit was obtained with a correlation coefficient ( R 2) of 0.9986. Hence, Raman spectroscopy represents a rapid non-destructive method to determine the degree of O-esterification in food proteins.

Study of Succinylated Food Proteins by Raman Spectroscopy

Three food protein products, soy protein isolates, spray-dried egg white, and whey protein isolates, were chemically modified to varying levels with succinic anhydride, and the extent of modification of these proteins were determined by standard wet chemistry methods. Raman spectra (500-2000 cm(-1)) of the modified proteins were obtained. New C=O stretching vibrations were observed at 1420 and 1737 cm(-1) and were attributed to the carboxylate (COO-) and ester carbonyl (RCOO-) groups, respectively, which were appended to the proteins during succinylation. Two series of calibration curves were obtained by plotting the intensity ratio of the 1420 and 1737 cm(-1) to 1003 cm(-1) phenylalanine stretching band (used as an internal standard) against the extent of substituted epsilon-amino (and alpha-amino) groups and aliphatic hydroxyl groups, respectively. Linear fits were obtained with correlation coefficient r > 0.988. The Raman spectral data were also analyzed to study the effect of succinylation on the conformation of the three proteins. Some conformational changes were observed, including a transition from ordered to disordered structures, an exposure of tryptophan residues from a buried, hydrophobic microenvironment, and probably conformational shift of cystine residues.

Dynamic and simultaneous analyses of gaseous sulfur and hydrocarbon compounds released during pyrolysis of coal

A flame ionization detector (FID) and a flame photometric detector (FPD) with a sulfur filter are coupled with a fixed-bed micro-reactor for temperature-programmed decomposition (TPD), TPD-FPD&FID, to allow simultaneously analysis of gaseous sulfur compounds and gaseous hydrocarbons released during pyrolysis of coals. As an example, a Chinese bituminous coal is used. Detailed experimental and quantification procedures are discussed. The results, mass of gaseous sulfur compounds and mass of gaseous hydrocarbons released as functions of pyrolysis temperature, can be used to analyze pyrolysis behavior and characteristics of sulfur and organic matrix in the coal. The results show that the method is reproducible with high accuracy in a wide range of experimental conditions, and the total amounts of sulfur determined by the FPD measurements are highly comparable to that obtained using a standard wet chemistry method.

An AFM Study of the Genesis and Sintering in Hydrogen of a Realistic Cu/Amorphous Silica Planar Model Catalyst

The genesis and subsequent sintering in a hydrogen atmosphere of realistic Cu/amorphous silica planar model catalysts have been investigated by atomic force microscopy. Samples were prepared by standard wet chemical methods followed by calcination and reduction, mimicking as closely as possible the procedures used in the preparation of practical, dispersed Cu catalysts. Changes in size distribution and mean particle size are observed as the sequence of transformations, Cu nitrate → cupric oxide → Cu metal, proceeds and an interpretation is offered. Pronounced sintering in hydrogen is the result of migration, agglomeration and coalescence of entire Cu particles, as opposed to Ostwald ripening. A mechanism for this process is proposed on the basis of absorption/desorption of hydrogen at steady state.

A new method for determining gossypol in cottonseed oil by FTIR spectroscopy

AbstractA new method was developed to determine the gossypol content in cottonseed oil using FTIR spectroscopy with a NaCl transmission cell. The wavelengths used were selected by spiking clean cottonseed oil to gossypol concentrations of 0–5% and noting the regions of maximal absorbance. Transmittance values from the wavelength regions 3600–2520 and 1900–800 cm−1 and a partial least squares (PLS) method were used to derive FTIR spectroscopic calibration models for crude cottonseed, semirefined cottonseed, and gossypol‐spiked cottonseed oils. The coefficients of determination (R2) for the models were computed by comparing the results from the FTIR spectroscopy against those obtained by AOCS method Ba 8‐78. The R2 were 0.9511, 0.9116, and 0.9363 for crude cottonseed, semirefined cottonseed, and gossypol‐spiked cottonseed oils, respectively. The SE of calibration were 0.042, 0.009, and 0.060, respectively. The calibration models were cross‐validated within the same set of oil samples. The SD of the difference for repeatability and accuracy of the FTIR method were better than those for the chemical method. With its speed (ca. 2 min) and ease of data manipulation, FTIR spectroscopy is a useful alternative to standard wet chemical methods for rapid and routine determination of gossypol in process and/or quality control for cottonseed oil.

FTIR spectroscopic determination of soap in refined vegetable oils

AbstractA new analytical method was developed for the determination of soap in palm and groundnut oils by FTIR spectroscopy. Soap from 0 to 80 mg/kg oil was produced in situ in the oils by adding sodium hydroxide. The FTIR spectroscopy was with a sodium chloride transmission cell, and the partial least‐squares statistical method was used to calibrate a model for each oil. The accuracy of the method was comparable to that of AOCS Method Cc17‐95, with coefficients of determination (R2) of 0.98 and 0.98 for both palm and groundnut oils. The standard errors of calibration were 1.84 and 1.36 for the two oils, respectively. The calibration models were cross‐validated, and the R2 of cross‐validation and standard errors of cross validation were computed. The standard deviation of the difference for repeatability of the FTIR method was better than that for the chemical method used for determining soap in palm and groundnut oils. With its speed and ease of data manipulation by computer software, FTIR spectroscopy is a possible alternative to the standard wet chemical methods for rapid (2 min) and accurate routine determination of soap in chemically refined vegetable oils.