Muhammad Abdul Qadir

Green Synthesis and Characterization of Silver Nanoparticles Using Ferocactus echidne Extract as a Reducing Agent

The green synthesis of silver nanoparticles using an aqueous extract of Ferocactus echidne(a member of the cactus family) as a reducing agent is reported. It is simple, efficient, rapid, and ecologically friendly compared to chemical-mediated methods. Ferocactus echidne is a plant of high medicinal value and rich in polyphenolic antioxidants. The extraction is simple and the product rapidly reduces silver ions without involvement of any external chemical agent. The reduction of silver nanoparticles was characterized by ultraviolet-visible spectrometry as a function of time and concentration. The results show that Ferocactus echidne reduces silver ions within 6 h depending upon the concentration. Further increases in reaction time may result in a blue shift, indicating an increase in particle size, whereas concentration had a minor effect on the particle size. The structure of synthesized nanoparticles was investigated by infrared spectroscopy, scanning electron microscopy, and X-ray diffraction. The infrared spectra indicated the association of organic materials with silver nanoparticles to serve as capping agents. Scanning electron micrographs showed that synthesized silver nanoparticles were nearly uniform and elliptical in shape with diameters of 20 to 60 nm. X-ray diffraction confirmed the formation of silver nanoparticles with an approximate 20 nm particle size calculated using the Debye-Scherer equation. Biological tests revealed that the silver nanoparticles were active against gram positive and negative bacteria( Escherichia coli and Staphylococcus aureus) and fungi (Candida albicans), indicating their broad spectrum antibiotic and antifungal abilities.

Determination of Aluminium by Electrothermal Atomization Atomic Absorption Spectrometry in Serum to Characterize Hemodialysis Toxicity

A simple and cost-effective method is described for the determination of aluminum by electrothermal atomic absorption spectrometry (ET-AAS) in serum of hemodialysis patients and healthy subjects. The only preparative step required is the dissolution of the serum sample in 0.2% magnesium nitrate matrix modifier and separate diluents 0.01 M EDTA and 0.1% Triton X-100. The calibration curve was linear from 20 to 100 µg/L with correlation coefficients of 0.9993 and 0.9998 for EDTA and Triton X-100, respectively. The sensitivity of the method for aluminum at the 309.3 nm line was 74 pg. The instrumental and method limits of detection were 2.2 µg/L and 4.4 µg/L, respectively. The aluminum concentrations of forty serum samples from hemodialysis patients and healthy subjects were determined and the mean values were 170.9 ± 6.8 µg/L and 47.3 ± 9.3 µg/L, respectively, whereas the permissible limit for aluminum in blood serum is 10 µg/L. The high level of Al in serum was related to oral phosphate binding agents and dialysis treatment.

Optimization and Validation Procedure for Elemental Composition of Fresh and Pasteurized Milk in Pakistan Employing Microwave Digestion Followed by ICP-OES: a Contribution to Risk Assessment

Inductively coupled plasma–optical emission spectrometry method for determination of macroelements (Ca, Mg, K, P, Na), trace elements (Cr, Cu, Fe, Mn, Se, Zn), non-essential element (Al), and toxic heavy metals (As, Cd, Pb) in fresh milk (n = 24) and pasteurized milk (n = 15) was optimized and validated. Analytical lines with low matrix affects and free from spectral interferences were selected for optimization and validation studies. Accuracy and precision were performed on certified milk samples and percent relative standard deviation (%RSD), and recovery results are in compliance with FDA guidelines for inductively coupled plasma–optical emission spectrometry (ICP-OES) methods for elemental composition in food stuffs. Significantly higher concentration of Al was found in both types of milk samples as compared with recommended standard for milk. No significant difference was found between the concentration of Pb and Cd in both samples. A strong positive correlation was found between Cu-Fe and Al-P. Correlations between other elements within each of analyzed samples were also found. The results indicate that particular attention should be paid to Al and Pb residues to control and confirm the absence of possible toxicological risks.

Evaluation of Phenolic Compounds and Antioxidant and Antimicrobial Activities of Some Common Herbs

The study was designed to evaluate the phenolic, flavonoid contents and antioxidant and antimicrobial activities of onion (Allium cepa), garlic (Allium sativum), mint (Mentha spicata), thyme (Thymus vulgaris), oak (Quercus), aloe vera (Aloe barbadensis Miller), and ginger (Zingiber officinale). All extracts showed a wide range of total phenolic contents, that is, 4.96 to 98.37 mg/100 g gallic acid equivalents, and total flavonoid contents, that is, 0.41 to 17.64 mg/100 g catechin equivalents. Antioxidant activity (AA) was determined by measuring reducing power, inhibition of peroxidation using linoleic acid system, and 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) scavenging activity. Different extracts inhibited oxidation of linoleic acid by 16.6–84.2% while DPPH radical scavenging activity (IC50 values) ranged from 17.8% to 79.1 μg/mL. Reducing power at 10 mg/mL extract concentration ranged from 0.11 to 0.84 nm. Furthermore the extracts of these medicinal herbs in 80% methanol, 80% ethanol, 80% acetone, and 100% water were screened for antimicrobial activity by disc diffusion method against selected bacterial strains, Staphylococcus aureus, Escherichia coli, Bacillus subtilis, and Pasteurella multocida, and fungal strains, Aspergillus niger, Aspergillus flavus, Rhizopus solani, and Alternaria alternata. The extracts show better antimicrobial activity against bacterial strains as compared to fungal strains. Results of various assays were analyzed statistically by applying appropriate statistical methods.

Amidine Sulfonamides and Benzene Sulfonamides: Synthesis and Their Biological Evaluation

New amidine and benzene sulfonamide derivatives were developed and structures of the new products were confirmed by elemental and spectral analysis (FT-IR, ESI-MS, 1HNMR, and 13CNMR). In vitro, developed compounds were screened for their antibacterial and antifungal activities against medically important bacterial strains, namely, S. aureus, B. subtilis, and E. coli, and fungi, namely, A. flavus, A. parasiticus, and A. sp. The antibacterial and antifungal activities have been determined by measuring MIC values (μg/mL) and zone of inhibitions (mm). Among the tested compounds, it was found that compounds 3b, 9a, and 9b have most potent activity against S. aureus, A. flavus, and A. parasiticus, respectively, and were found to be more active than sulfamethoxazole and itraconazole with MIC values 40 μg/mL. In contrast, all the compounds were totally inactive against the A. sp. except 10b and 15b to show activity to some extent.

Physiochemical, Biochemical, Minerals Content Analysis, and Antioxidant Potential of National and International Honeys in Pakistan

16 honey samples from Pakistan and two other countries were investigated for their physiochemical, biochemical, minerals, and antioxidant potential. Antioxidant activities of all honey samples were performed by using percentage inhibition of DPPH free radical, AEAC, and FRAP. 5-HMF and mineral contents were determined by HPLC and AAS, respectively. The obtained values of respective parameters, namely, pH, EC, TDS, total acidity, moisture, ash, color intensity, sugars, proline, and protein were in compliance with codex standard and recommendation of council directive by European Union. The total phenolics contents in acacia honey from Germany and jujube honey from Pakistan are similar to monofloral honey from Saudi Arabia and Yemen, respectively. The mineral contents in tested honey samples are comparable with honey from Brazil and Romania. Dark color honeys contained higher phenolic contents than light color ones and attributed to higher oxidation potential and have strong positive correlation with DPPH and FRAP.

Erratum to: Quantitation and Risk Assessment of Chemical Adulterants in Milk Using UHPLC Coupled to Photodiode Array and Differential Refractive Index Detectors

Milk can be adulterated illegitimately with formaldehyde, melamine, urea, and sugars for preservation, protein content enhancement, and taste improvement, respectively. In the present study, formaldehyde, melamine, urea, and sugars (fructose, glucose, lactose, sucrose) were analyzed using ultra-fast high performance liquid chromatography in 30 fresh and pasteurized milk samples. Satisfactory chromatographic retention and peak shape investigated and method has been validated by means of recovery experiments in samples spiked at two levels. Average recoveries ranged between 95–105 % with excellent precision; RSD lower than 5 % was achieved. Among the tested samples, formaldehyde was detected in all samples while seven and 20 samples were positive for melamine and sucrose, respectively. Monitoring of these adulterants in milk could help to reduce the human health hazards. Exposure to formaldehyde, melamine, and urea from consumption of milk was estimated, and these were less than 3.3, 1, and 700 μg/mL, respectively, which is an oral reference dose suggested by the World Health Organization and US Food and Drug Administration.

Evaluation of trace elemental composition of aerosols in the atmosphere of Rawalpindi and Islamabad using radio analytical methods.

Geological and anthropogenic contributions to air pollution were monitored by analyzing aerosol particulates present in the atmosphere of Rawalpindi and Islamabad, Pakistan, using instrumental neutron activation for trace elemental analysis. A scanning electron microscope was used to study particulate size distribution and morphology. Twenty two elements were analyzed and their likely sources were identified. It was found that 69% of the suspended particulate matter in the atmosphere of Islamabad, and 52% in Rawalpindi, were of a diameter less than 3 μm. The presence of Yb, Cs, Sc, Rb, Co, Eu, La, Ba, Zn and Hf indicates that a major portion of the trace elements in the aerosol particulates was due to the geological nature of the land, while Sc was considered to be arising from coal burning. The presence of Cr, Fe, Ce, Pb and Cd was attributed to anthropogenic activities at Rawalpindi and Islamabad. Unusually high concentrations of Mo and Nb were found in the atmosphere of Islamabad, based on soil derived aerosols.

Preparation of high purity nickel film from industrial effluent by the distribution of charge over microelectrodes using newly designed free electrolytic diffusion approach

The present work deals with the development of a newly designed free electrolytic diffusion approach (the distribution of charge over microelectrodes) for the purification of metals and was successfully applied for the purification of nickel from the industrial effluent containing high proportion of nickel. Atomic absorption spectrophotometer (AAS) analyzed the purified nickel deposited on working microelectrodes. The results obtained show that the purity of nickel was enhanced from 95% to 99.9% with traces of copper etc. It was concluded that distribution of charge over the microcathodes at a rate of 50 cycles per second (cps) shows better results for the production of high purity (HP) nickel as compared to 25 cycles per second (cps).

Comprehensive two-dimensional ion chromatography (2D-IC) coupled to a post-column photochemical fluorescence detection system for determination of neonicotinoids (imidacloprid and clothianidin) in food samples

There are increasing concerns about the dietary risks of neonicotinoids (NNIs); therefore their sensitive and accurate determination in dietary products is indispensable. However, the complex composition of agricultural food matrixes makes their extraction and quantitative determination a challenging task. Realizing this need, we herein report a simple, cost-effective, selective and sensitive fluorescence analytical workflow for analyses of two non-fluorescent neonicotinoids imidacloprid (IMI) and clothianidin (CLT) in six complex food samples (honey, ginger, durian, apple, tomato, cucumber) by online clean-up of sample extracts using two-dimensional ion chromatography (2D-IC) and a subsequent online post column UV induced fluorescence detection system. This online clean-up setup has proven advantageous to improve the limit of detection, potentially diminish matrix effects, and reduce analysis time and labor. The developed method showed excellent analytical figures of merit including linearity, selectivity, repeatability, recovery, and resolution for analysis of IMI and CLT in food samples.