Coupling of carboxymethyl starch with 2-carboxyethyl acrylate: A new sorbent for the wastewater remediation of methylene blue.

Textile and printing industries play a vital role in the economy of any country. But the effluents of these industries, which contain toxic Methylene Blue (MB) dye when mixed with fresh water, make it unfit for human health and aquatic life. For the removal of MB, different adsorbents were used, but they were expensive, non-biodegradable or less effective. In this research, novel carboxymethyl starch grafted poly 2-carboxyethyl acrylate (CM-St-g-P2CEtA) was synthesized by reacting carboxymethyl starch with 2-carboxyethyl acrylate. The reaction followed a free radical polymerization mechanism. The structure and properties of CM-St-g-P2CEtA were investigated by advanced analytical techniques. The CM-St-g-P2CEtA was employed for the remediation of Methylene Blue (MB) dye from wastewater. The removal percentage (%R) of MB was checked under different parameters, like different pH levels, different initial concentrations of dye, different adsorbent doses, and different contact times. The results obtained during the experiment were subjected to different adsorption and kinetic models. In the kinetic investigation, the experimental results were best represented by the pseudo-second-order kinetic model due to its high R2 value of 0.999. Similarly, with a regression coefficient (R2) value of 0.947, the Langmuir adsorption isotherm was best represented by the experimental results. The Langmuir adsorption model showed that MB dye was adsorbed on the surface of CM-St-g-P2CEtA in a monolayer pattern. The pseudo 2nd order kinetic model suggested that the adsorption process favored chemisorption mechanism. The CM-St-g-P2CEtA showed maximum percentage removal efficiency (%R) of 99.3% for MB dye.

Microwave Irradiation Assists the Synthesis of a Novel Series of bis-Arm s-Triazine Oxy-Schiff Base and Oxybenzylidene Barbiturate Derivatives.

A novel series of s-triazines incorporating 4-hydroxybenzaldehyde and 4-hydroxy-3-methoxybenzaldehyde was prepared and fully characterized. The reaction was carried out via stepwise nucleophilic aromatic substitution of chlorine atoms in cyanuric chloride. The first chlorine was substituted by different amines (morpholine, piperidine, or diethylamine) to afford 2,4-dichloro-6-substituted-1,3,5-triazine. The second and third chlorines were substituted by benzaldehyde derivatives in the presence of Na2CO3 as a HCl scavenger to afford the target products: s-triazine oxyaldehyde derivatives (dipodal). The dipodal derivatives were reacted with acid hydrazide, hydralazine, barbituric, or thiobarbituric acid derivatives using conventional heating or microwave irradiation to afford the di-arm s-triazine oxy-Schiff base and oxybenzylidene barbiturate derivatives in good yields. Microwave irradiation done in less solvent afforded the target product in less reaction time with good yield and purity. These types of derivatives might have special interest in coordination and medicinal chemistry.

Functionalized nanoparticles based solid-phase membrane micro-tip extraction and high-performance liquid chromatography analyses of vitamin B complex in human plasma.

Iron nanoparticles were prepared by a green method following functionalization using 1-butyl-3-methylimidazolium bromide. 1-Butyl-3-methylimidazole iron nanoparticles were characterized using FTIR spectroscopy, energy dispersive X-ray fluorescence, X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The nanoparticles were used in solid-phase membrane micro-tip extraction to separate vitamin B complex from plasma before high-performance liquid chromatography. The optimum conditions obtained were sorbent (15 mg), agitation time (30 min), pH (9.0), desorbing solvent [water (5 mL) + methanol (5 mL) + sodium hydroxide (0.1 N) + acetic acid (d = 1.05 kg/L, pH 5.5), desorbing volume (10 mL) and desorption time (30 min). The percentage recoveries of all the eight vitamin B complex were from 60 to 83%. A high-performance liquid chromatography method was developed using a PhE column (250 × 4.6 mm, 5.0 µm) and water/acetonitrile (95:5, v/v; pH 4.0 with 0.1% formic acid) mobile phase. The flow rate was 1.0 mL/min with detection at 270 and 210 nm. The values of the capacity, separation and resolution factor were 0.57-39.47, 1.12-6.00 and 1.84-26.26, respectively. The developed sample preparation and chromatographic methods were fast, selective, inexpensive, economic and reproducible. The developed method can be applied for analyzing these drugs in biological and environmental matrices.

Enantiomeric resolution of multiple chiral centres racemates by capillary electrophoresis.

Enantiomeric resolution of multichiral centre racemates is an important area as some multichiral centre racemates are of great medicinal importance. However, enantioseparation of such types of racemates is a challenging task. Amongst many analytical techniques, capillary electrophoresis is a powerful technique and may be used to resolve such racemates. Only few papers are available describing enantiomeric resolution of such racemates. Therefore, efforts have been made to describe the enantiomeric resolution of multichiral centre racemates by capillary electrophoresis. This article discusses the importance of multichiral racemates, the need for capillary electrophoresis in enantiomeric resolution and chiral resolution of multichiral centre racemates using various chiral selectors. Further, attempts have been made to discuss the future challenges and prospects of enantiomeric resolution of multichiral racemates. The various chiral selectors used for the purpose are chiral crown ether, cyclodextrins, polysaccharides, macrocyclic glycopeptide antibiotics and ligand exchange.

sym-Trisubstituted 1,3,5-Triazine Derivatives as Promising Organic Corrosion Inhibitors for Steel in Acidic Solution.

Triazine derivatives, namely, 2,4,6-tris(quinolin-8-yloxy)-1,3,5-triazine (T3Q), N²,N4,N6-tris(pyridin-2-ylmethyl)-1,3,5-triazine-2,4,6-triamine (T3AMPy) and 2,2',2''-[(1,3,5-triazine-2,4,6-triyl)tris(azanediyl)] tris(ethan-1-ol) (T3EA) were synthesized and their inhibition of steel corrosion in hydrochloric acid solution was investigated using electrochemical techniques. The corrosion protection of the prepared compounds increased with increasing concentration and reached up to 98% at 250 ppm. The adsorption of T3Q, T3AMPy, and T3EA on the steel surface was in accordance with the Langmuir adsorption isotherm. The electrochemical results revealed that T3Q, T3AMPy and T3EA act as excellent organic inhibitors and can labeled as mixed type inhibitors. The efficiencies of the tested compounds were affected by the nature of the side chain present in the triazine ring, where T3EA gave the least inhibition while T3Q and T3AMPy gave higher and almost the same inhibition effects. The inhibition efficiencies obtained from the different electrochemical techniques were in good agreement.

Enantiomeric separation and simulation studies of pheniramine, oxybutynin, cetirizine, and brinzolamide chiral drugs on amylose-based columns.

Solid phase extraction (SPE)-chiral separation of the important drugs pheniramine, oxybutynin, cetirizine, and brinzolamide was achieved on the C18 cartridge and AmyCoat (150 x 46 mm) and Chiralpak AD (25 cm x 0.46 cm id) chiral columns in human plasma. Pheniramine, oxybutynin, cetirizine, and brinzolamide were resolved using n-hexane-2-PrOH-DEA (85:15:0.1, v/v), n-hexane-2-PrOH-DEA (80:20:0.1, v/v), n-hexane-2-PrOH-DEA (70:30:0.2, v/v), and n-hexane-2-propanol (90:10, v/v) as mobile phases. The separation was carried out at 25 ± 1 ºC temperature with detection at 225 nm for cetirizine and oxybutynin and 220 nm for pheniramine and brinzolamide. The flow rates of the mobile phases were 0.5 mL min(-1). The retention factors of pheniramine, oxybutynin, cetirizine and brinzolamide were 3.25 and 4.34, 4.76 and 5.64, 6.10 and 6.60, and 1.64 and 2.01, respectively. The separation factors of these drugs were 1.33, 1.18, 1.09 and 1.20 while their resolutions factors were 1.09, 1.45, 1.63 and 1.25, and 1.15, respectively. The absolute configurations of the eluted enantiomers of the reported drugs were determined by simulation studies. It was observed that the order of enantiomers elution of the reported drugs was S-pheniramine > R-pheniramine; R-oxybutynin > S-oxybutynin; S-cetirizine > R-cetirizine; and S-brinzolamide > R-brinzolamide. The mechanism of separation was also determined at the supramolecular level by considering interactions and modeling results. The reported SPE-chiral high-performance liquid chromatography (HPLC) methods are suitable for the enantiomeric analyses of these drugs in any biological sample. In addition, simulation studies may be used to determine the absolute configuration of the first and second eluted enantiomers.

Advances in enantiomeric resolution on monolithic chiral stationary phases in liquid chromatography and electrochromatography.

During the last decade, chiral monolithic stationary phases have been prepared and used for rapid enantioseparations in CEC and HPLC. Various chiral selectors are used to prepare these CSPs. The preparation, properties, and applications of these CSPs are discussed in this paper. Attempts have been made to describe optimization strategies and the chiral recognition mechanisms. A comparison of chiral separations in CEC and HPLC is described. Efforts have also been made to predict the future perspectives and challenges of chiral monolithic stationary phases. The most effective chiral selectors include polysaccharides, cyclodextrins, and macrocyclic glycopeptide antibiotics. These chiral phases produced acceptable analytical enantiomeric separation of a variety of racemates. However, the development of these CSPs for preparative-scale separations is needed.

Advances in chiral separations of small peptides by capillary electrophoresis and chromatography.

Many chemical and biological processes are controlled by the stereochemistry of small polypeptides (di-, tri-, tetra-, penta-, hexapeptides, etc). The biological importance of peptide stereoisomers is of great value. Therefore, the chiral resolution of peptides is an important issue in biological and medicinal sciences and drug industries. The chiral resolutions of peptide racemates have been discussed with the use of capillary electrophoresis and chromatographic techniques. The various chiral selectors used were polysaccharides, cyclodextrins, Pirkle types, macrocyclic antibiotics, crown ethers, imprinted polymers, etc. The stereochemistry of dipeptides is also discussed. Besides, efforts are made to explain the chiral recognition mechanisms, which will be helpful in understanding existing and developing new stereoselective analyses. Future perspectives of enantiomeric resolution are also predicted. Finally, the review concludes with the demand of enantiomeric resolution of all naturally occurring and synthetic peptides.

Enantio-separation of drugs with multiple chiral centers by chromatography and capillary electrophoresis.

Some drugs with more than one chiral center are of high medicinal values. However, the chiral resolution of such types of racemate is a challenging task for scientists. The evolution of efficient chiral selectors is a hope for the future. Some papers have described such types of chiral resolution. The different techniques used for the purpose are HPLC, micellar electrokinetic chromatography, supercritical fluid chromatography, capillary electrochromatography and capillary electrophoresis. Owing to these facts, it was necessary to review the enantiomeric resolution of racemic drugs having more than one chiral center. The present article describes the chiral resolution of labetalol, formoterol, nadolol, indenolol, nebivolol and diltiazem using above cited techniques. In addition, attempts have been made to discuss the chiral recognition mechanism and future perspectives.

Seasonal concentrations of lead in outdoor and indoor dust and blood of children in Riyadh, Saudi Arabia.

Because detrimental effects of exposure to lead (Pb) on human health have been observed, we previously investigated concentrations of Pb in water supplies and blood of adult residents of Riyadh, Saudi Arabia. The objectives of the present study were to: (1) examine seasonal rates of deposition of Pb in dust in several areas of Riyadh city, (2) measure concentrations of Pb in both outdoor and indoor dust, (3) compare concentrations of Pb in dust in Riyadh with those reported for other cities, and (4) quantify Pb in blood of children living in Riyadh. Mean, monthly deposition of PB in outdoor dust was 4.7 × 10(1) ± 3.6 tons km(-2), with a mean Pb concentration of 2.4 × 10(2) ± 4.4 × 10(1) µg/g. Mean, monthly deposition of Pb in indoor dust was 2.7 ± 0.70 tons km(-2), with a mean concentration of 2.9 × 10(1) ± 1.5 × 10(1) µg Pb/g. There was a significant (P < 0.01) correlation between concentrations of Pb in outdoor and indoor dust. There was no correlation between concentrations of Pb in indoor dust and that in blood of children of Riyadh, whereas there was a weakly significant (P < 0.05) correlation between concentrations of Pb in outdoor dust and that in blood of children. The mean (±SD) concentration of Pb in blood of children in Riyadh was 5.2 ± 1.7, with a range of 1.7-1.6 × 10(1) µg/dl. Concentrations of Pb in blood of 17.8 % of children in Riyadh were greater than 10 µg/dl, which is the CDC's level of concern.

Cyclo-hexyl-ammonium nitrate.

In the title salt, C6H14N(+)·NO3 (-), the cyclo-hexyl ring adopts a chair conformation. The ammonium group occupies an equatorial position and the crystal struture is stabilized by inter-molecular N-H⋯O hydrogen-bonding inter-actions, resulting in a three-dimensional network.

Effect of multi-walled carbon nanotubes incorporation into benzyl methacrylate monolithic columns in capillary liquid chromatography.

This work describes the preparation of polymer based monolithic materials and their use as stationary phases in capillary liquid chromatography. Multi-walled carbon nanotubes (MWCNT) were incorporated into a mixture containing benzyl methacrylate (BMA) and ethylene dimethacrylate (EDMA) as co-monomers. The optimized porogenic mixture was a ternary solution composed of cyclohexanol, 1,4-butandiol and butanol which resulted in a stable and homogeneous suspension. Six capillary columns with increasing amounts of MWCNT, from 0 to 0.4 mg mL(-1), were prepared by thermal polymerization in 0.32 mm (i.d.) and 150 mm length fused silica tubing. The chromatographic evaluation showed that the synthesized monolithic beds were mechanically stable while their porosity and permeability increased with the MWCNT content. The prepared capillary columns were tested for the separation of mixtures of ketones and phenols at an optimum flow rate of 2 µL min(-1). The results showed that incorporation of MWCNT slightly affected the retention while it enhanced the column efficiency by increasing the column efficiency by a factor of up to 9. This effect corresponded also to an improved resolution and full separation of the solutes.

Recent trends in ultra-fast HPLC: new generation superficially porous silica columns.

New generation columns, i.e. packed with superficially porous silica particles are available as trade names with following manufacturers: Halo, Ascentis Express, Proshell 120, Kinetex, Accucore, Sunshell, and Nucleoshell. These provide ultra-fast HPLC separations for a variety of compounds with moderate sample loading capacity and low back pressure. Chemistries of these columns are C(8), C(18), RP-Amide, hydrophilic interaction liquid chromatography, penta fluorophenyl (PFP), F5, and RP-aqua. Normally, the silica gel particles are of 2.7 and 1.7 µm as total and inner solid core diameters, respectively, with 0.5-µm-thick of outer porous layer having 90 Å pore sizes and 150 m(2)/g surface area. This article describes these new generation columns with special emphasis on their textures and chemistries, separations, optimization, and comparison (inter and intra stationary phases). Besides, future perspectives have also been discussed.

Rapid and economic chiral-HPLC method of nebivolol enantiomers resolution in dosage formulation.

A fast, economic, reproducible, accurate, effective, rugged and selective chiral-HPLC method was developed and validated for the enantiomeric resolution of nebivolol enantiomers [(+)-RRRS and (-)-SSSR)] in dosage formulation. The method was rapid as chiral separation occurred within only 12 min. The mobile phase used was n-heptane-ethanol-DEA (85:15:0.1, v/v) at 3.0 mL/min flow-rate with 225 nm detection. The column used was an amylase-based 3-AmyCoat (150 × 46 mm) [tris-(3,5-dimethylphenyl carbamate)]. The capacity factors of (+)-RRRS and (-)-SSSR enantiomers were 7.85 and 10.90 while the separation and resolution factors were 1.39 and 1.83, respectively. The limits of detection and quantitation for (+)-RRRS enantiomer were 4.5 and 10.00 µg/mL, while these values for (-)-SSSR enantiomer were 4.1 and 8.2 µg/mL, respectively. The linearity was observed in the concentrations range of 0.10-1.0 mg/mL for both enantiomers. The π-π interactions, hydrogen bonds, dipole-dipole interactions and steric effects control the chiral resolution of nebivolol enantiomers on the reported chiral column. The reported method can be used for the quality control of nebivolol in pharmaceutical preparations with good economy. In addition, this method can also be used for the analysis of (+)-RRRS and (-)-SSSR) enantiomers in biological and environmental samples.

Superficially porous particles columns for super fast HPLC separations.

Superficially porous silica particles columns (SPSPCs) are manufactured by different companies. The most common have the brand names Halo, Ascentis Express and Kinetex. These columns provide super fast, sharp peaks and moderate sample loading and back pressure. These are available in different chemistries such as C8, C18, RP Amide and Hilic. Normally, the silica gel particles have 2.7 and 1.7 µm total and inner solid core diameters with 0.5 µm thick outer porous layer, 90 Å pore size and 150 m²/g surface area. They have been used for the separation and identification of low and high molecular weight compounds. The present article describes the state of the art of superficially porous silica particles based columns with special emphasis on their structures, mechanisms of separation, applications and comparison.

A practical chemo-enzymatic approach to highly enantio-enriched 10-ethyl-7,8-dihydro-γ-ionone isomers: a method for the synthesis of 4,5-didehydro-α-ionone.

An efficient and convenient strategy for the enantioselective synthesis of enantiomerically enriched 10-ethyl-7,8-dihydro-γ-ionone isomers (R)-(+)-7, and (S)-(-)-7 are described utilizing a lipase mediated resolution protocol, and reductive elimination of the secondary allylic alcohol as the key step. The enantioselective and diastereoselective lipase kinetic acetylation of 4-hydroxy-γ-ionone derivatives 6a afforded the 4-acetyl-γ-ionone derivatives (-)-8, and the 4-hydrox-γ-ionone derivatives (+)-6a, which are suitable precursors of the desired products. Stereospecific palladium-mediated elimination of allylic acetate provides the target compounds with an excellent enantiomeric excess and yield. Additionally, the novel 4,5-didehydro-α-ionone 13 is obtained from readily prepared (2,6,6-trimethylcyclohexa-2,4-dien-1-yl) methanol 9. The structures of all newly synthesized compounds have been elucidated by (1)H, (13)C NMR, GC-MS, and IR spectrometry. These compounds represent a new class of odorants that may be of pivotal relevance in industrial perfumery.

Daily intake of selenium and concentrations in blood of residents of Riyadh City, Saudi Arabia.

Concentrations of selenium (Se) in food from local markets of Riyadh, Kingdom of Saudi Arabia (KSA) were measured and daily intake calculated based on information from a questionnaire of foods eaten by healthy Saudis. The daily intake of Se was then compared to concentrations of Se in blood serum. Primary sources of Se in the diet of Saudis were as follows: meat and meat products (31%), egg (20.4%), cereals and cereal products (16%), legumes (8.7%), fruits (6.8%), milk and dairy products (2.0%), beverages (2%), sweets (1.8%), pickles (0.2%), and oil (0.02%). Daily intake of Se, estimated to be 93 µg Se/person/day, was slightly greater than that calculated from the Food and Agriculture Organization (FAO) food balance sheet for KSA, which was approximately 90 µg Se/person/day. The daily intake of Se by Saudis in Riyadh was greater than that of Australians or Dutch but less that of Canadians and Americans. There was a statistically significant correlation (R = +0.38, P < 0.05) between daily intake of Se and concentrations of Se in blood serum of Saudis in Riyadh. The mean concentration of Se in serum was 1.0 × 10(2) ± 30.5 µg Se/l. Taken together, the results suggest that the average Se intake and Se serum concentrations are within the known limits and recommendations, making it unlikely that Saudis are on average at risk of deficiency or toxicity.

Evaluation of trace metals in tea samples from Jeddah and Jazan, Saudi Arabia by atomic absorption spectrometry.

The Cd, Pb, Mn, Zn, Ni, Co, Fe, Cr and Cu content were determined in various teas available in local markets of Jeddah and Jazan, Saudi Arabia. Concentrations of the trace metals were measured after acid digestion using a flame atomic absorption spectrometer. Validation of the digestion procedure was performed by the analysis of a certified reference material. The cadmium, lead, manganese, zinc, nickel, cobalt, iron, chromium and copper concentrations were found in the range of below the detection limit (BDL)--0.7 µg/g, BDL--8.7 µg/g, 48-859 µg/g, 6.6-120 µg/g, BDL--16.9 µg/g, BDL--3.1 µg/g, 46-348 µg/g, BDL--4.9 µg/g and 5.2-21.6 µg/g respectively. The values found in this study were compared with literature values.

Three new cycloartane triterpenoids from Astragalus bicuspis.

Three new cycloartane triterpenoids have been isolated from Astragalus bicUSPIS Fisch. Their structures were elucidated as 23(R),24(S),25( R),26(S)-16 ß/23,23/26,24/25-triepoxy-26-hydroxy-9,19-cyclolanosta-3,6-dione (1), 6 α,23,24,25-tetraol-16 ß-acetoxy-23(R),24(R)-9,19-cyclanosta-3-one (2), and 6 α,23,24,25-tetraol-16 ß-acetoxy-23(R),24(R)-9,19-cyclolanosta-3 ß- O-xyloside (3), based on their spectroscopic analysis. All cycloartane tritepenoids exhibited weak cytotoxicities against 3T3 fibroblast cells as compared to the standard drug cycloheximide. Compounds 3 and 4 were also tested for their antileishmanial potential, and a weak activity was observed against promastigotes of Leishmania major.

Effects of Mesembrrybryanthemum forsskalei Hochst seeds in lowering glucose/lipid profile in streptozotocin-induced diabetic rats.

The aim of present investigation was to study the effects of Mesembryanthemum forsskalei Hochst (Samh) seeds in streptozotocin-induced diabetic rats. Thirty rats were administrated with streptozotocin to induce diabetes and 6 rats were used as untreated diabetic control. Diabetic rats were fed with 5 and 15% Samh seed alone and in combination with fatty diet i.e. 2% Cholesterol for 6 weeks. Effects of Samh seed on blood glucose levels, lipid profiles and enzyme activities of diabetic rats were examined. In addition, total cholesterol (TC), triglyceride (TG) and high density lipoprotein-cholesterol (HDL-C) were determined. Diabetic rats treated with 15% Samh seed diet were significantly decreased the level of TC (40%), TG (46%) and HDL-C (31%) respectively. Whereas, there was no significant effects observed in the glucose level in 15% Samh seeds treated rats for 6 weeks. A decrease in enzymes levels, AST (58.2%), LDH (1.6%), ALT (24.3%) and ALP (5.38%) in 5% Samh seeds diet treated rats were observed and were found near to untreated control. Findings from present study demonstrated that non fatty Samh seeds diet could have hypoglycemic and antihyperlipidemic effects in diabetic rats and could be useful model for the treatment of diabetic patients.