DETERMINATION OF NITRITE, NITRATE AND TOTAL NITROGEN IN VEGETABLE SAMPLES

Yellow diazonium cation formed by reaction of nitrite with 6-amino-1-naphthol-3-sulphonic acid is coupled with β-naphthol in strong alkaline medium to yield a pink coloured azo dye. The azo-dyes shows absorption maximum at 510 nm with molar absorptivity of 2.5 ×104 M-1 cm-1. The dye product obeys Beer\'s law (correlation coefficient = 0.997), in terms of nitrite concentration, up to 2.7 μg NO2 mL-1. The above colour reaction system has been applied successfully for the determination of nitrite, nitrate and total nitrogen in vegetable samples. Unreduced samples give direct measure for nitrite whilst reduction of samples by copperized-cadmium column gives total nitrogen content and their difference shows nitrate content in the samples. Variety of vegetables have been tested for their N-content (NO2-/NO3-/total-N) with % RSD ranging between 1.5 to 2.5 % for nitrite determination. The effects of foreign ions in the determination of the nitrite, nitrate, and total nitrogen have been studied. Statistical comparison of the results with those of reported method shows good agreement and indicates no significant difference in precision. KEY WORDS: Yellow diazonium cation, 6-Amino-1-naphthol-3-sulphonic acid, Vegetables, Nitrite in vegetables, Nitrate in vegetables, Total nitrogen in vegetables Bull. Chem. Soc. Ethiop. 2007, 21(3), 445-450

Ion-pair single-drop microextraction with ATR-FTIR determination of phosphate in water samples

A simple, rapid and green ion-pair single-drop microextraction procedure followed by attenuated total reflectance-Fourier transform infrared technique has been developed for the analysis of phosphate in water samples. This method is based on the extraction of the phosphate-cetyltrimethylammonium bromide ion-pair by the single-drop extraction procedure. The linear range for calibration plot of phosphate is 1-900 ng mL-1, with good correlation coefficient (r2 = 0.998). The limit of detection, limit of quantification, standard deviation and relative standard deviation of six replicate measurements are respectively 0.34 ng mL-1, 1.12 ng mL-1, 0.001 and 0.94-3.36%. The significant parameters such as selection of solvent, their volume, ion-pair reagent and their concentration, extraction time, stirring rate, sample pH, extraction temperature and effect of salt concentration are studied and optimized. The present method is successfully applied for the quantification of phosphate in water samples with minimal solvent consumption and sensitivity as compared with the conventional methods

Evaluation of the phytochemical and mineral characteristics of some selected Sapotaceae plants

Aims: To study the spectral and thermal characteristics, and the oil, starch, polyphenol and mineral contents of seeds and leaves from three Sapotaceae species, provided that trees and shrubs of this family are an important source of nutritional and functional products. Methodology: Leaves and seeds from three Sapotaceae plants, namely Moa tree (Madhuca indica J. F. Gmel.), Chico sapote (Manilkara zapota (Linn.) van Royen) and Spanish cherry (Mimusops elengi Linn.), were collected in the Raipur area of Chhattisgarh, India. Their physicochemical characterization (including oil, polyphenol, starch and mineral contents; functional groups; and thermal degradation patterns) was carried out by using various techniques, viz. solvent extraction, spectrophotometry, enzymatic digestion, X-ray fluorescence (XRF) and Fourier-transform infrared (FTIR) spectroscopies, thermogravimetric/derivative thermogravimetric (TG/DTG) and differential scanning calorimetry (DSC), respectively. Results: The three Sapotaceae seeds under study were found to contain polyphenol, mineral, starch and oil contents in the 1850–23180 mg/kg, 11390–19385 mg/kg, 6.7–9.1% and 9.8-54.1% range, respectively. Their leaves and seed coats featured total phenolic contents in the 24260–28600 mg/kg and 7810–23060 mg/kg range, respectively, and mineral contents in the 8823–27462 mg/kg and 3619–15884 mg/kg range, respectively. The functional groups of the phytochemicals, studied by FTIR, were assigned. Their thermal decomposition patterns, which involved loss of water and volatile organic compounds, proteins, oil and starch/cellulose, were also described. Conclusion: The Sapotaceae leaves, seed coat, kernel and cake are enriched with very high contents of starch, proteins, polyphenols and minerals, suggesting their possible valorization in human food, animal feeding and as herbal medicines

Procjena i vrednovanje PM2.5 u vanjskom okolišu u odnosu na njegove zdravstvene učinke u industrijskim područjima u kojima se koristi mineralni ugljen

Atmospheric PM2.5 pollution, has shown potential impact on the human health in general, thus it requires to look into the chemical characteristics of PM2.5 masses for designing effective policies to reduce health risks amongst public under exposure. The study carried out, here, has presented the ambient PM2.5 concentrations, concentrations of chemical components and associated health risks over rural and urban environments in the area of mineral based coal-fired industrial areas of central India for a period of one year (2015–16). Overall 260 PM2.5 samples, collected from rural, urban and industrial sites, were analyzed for various elements Al, As, Ca, Hg, Cr, Co, Cu, Fe, Mn, K, Cd, Mo, Ni, Pb, Se, Sb, Na, Mg, K, V and Zn, ions such as Na+, Mg2+, K+, Ca2+, F–, Cl–, NH4+, NO3–, SO42– and carbonaceous matter. The annual average PM2.5 mass concentrations were found to be ~2 to ~6 folds higher than the annual National Ambient Air Quality standard (40 µg m–3). Further this study also evaluates, carcinogenic and non-carcinogenic health risks associated with ambient PM2.5 exposures (via ingestion, inhalation and dermal). The elemental species that have shown non-carcinogenic risks for both children and adults of all three sites are: Co, Mn, Ni (rural), As, Cd, Cr, Mn, Ni, V (urban and industrial sites). Similarly, the excess carcinogenic risks, in total, from Cd, Co, Cr, Ni, Pb was found to be higher than acceptable limits (10–6 to 10–4).Onečišćenje atmosfere lebdećim česticama (PM2.5) pokazalo je potencijalni utjecaj na zdravlje ljudi općenito. Stoga je potrebno sagledati kemijska svojstva čestica PM2.5 kako bi se postiglo učinkovito smanjenje zdravstvenih rizika izložene populacije. U ovome radu prikazuju se rezultati studije koncentracija PM2.5 i koncentracija kemijskih sastojaka u lebdećim česticama za jednogodišnje razdoblje (2015.–2016.) koji su povezani sa zdravstvenim rizicima u ruralnim i urbanim sredinama u industrijskim područjima u središnjoj Indiji u kojima se koristi mineralni ugljen kao pogonsko industrijsko gorivo. Ukupno je analizirano 260 uzoraka PM2.5 s ruralnih, urbanih i industrijskih lokacija za različite elemente: Al, As, Ca, Hg, Cr, Co, Cu, Fe, Mn, K, Cd, Mo, Ni, Pb, Se , B, Na, Mg, K, V i Zn, ione poput Na+, Mg2+, K+, Ca2+, F–, Cl–, NH4+, NO3–, SO42– i spojeve ugljika. Utvrđeno je da su prosječne godišnje masene koncentracije PM2.5 od ~2 do ~6 puta više od dopuštenih godišnjih vrijednosti prema indijskom Nacionalnom standardu kvalitete zraka (40 µgm–3). Nadalje, ova studija također ocjenjuje kancerogene i nekancerogene rizike za zdravlje povezane s izloženošću česticama PM2.5 u okolišu (putem gutanja, udisanja i dodira s kožom). Elementi koji su pokazali nekancerogene rizike i za djecu i za odrasle na sve tri lokacije su: Co, Mn, Ni (ruralno područje), As, Cd, Cr, Mn, Ni i V (urbano i industrijsko područje). Slično, utvrđen je povećan kancerogeni rizik za Cd, Co, Cr, Ni i Pb, koji je veći od prihvatljivih granica (10–6 do 10–4)

BTEX in ambient air of India: a scoping review of their concentrations, sources, and impact

Toxic gaseous organic air pollutants such as benzene, toluene, ethylbenzene, and xylene isomers (m, p, and o-x) (BTEX) are considered hazardous due to its adverse impacts on human health and on climate change. This review identifies the major research questions addressed so far and the research gap in research articles, published between 2001 and 2022, focusing on the ambient BTEX concentrations in different locations in India along with its sources, ozone formation potential (OFP), and associated health risks. The ambient levels of BTEX were also compared with those of other Asian countries. A comparison of ambient BTEX levels with different microenvironments in India is also presented. BTEX concentrations were found in the range of 30.95 to 317.18 µg m−3 and multi-fold higher in urban environments than those measured in the rural air. In most reported studies, the order of occurrence of BTEX compounds was toluene > benzene > xylene isomers > ethylbenzene and winter had higher concentrations than in other seasons, including summer. As far as BTEX levels in classified areas of urban environments are concerned, traffic locations have shown the highest BTEX concentrations, followed by residential, commercial, and industrial locations. OFP indicated that xylene isomers and toluene contributed to ozone formation. The major gaps in reported studies on BTEX measurement are (1) source apportionment; (2) impact on lower tropospheric chemistry, human health, and climate change; and (3) removal techniques from air.publishe

Removal of phenol in aqueous solution by adsorption onto green synthesized coinage nanoparticles beads

The adsorption of phenol from aqueous solution was carried out by using alginate-stabilized silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs) beads as adsorbents. The resulting AgNPs and AuNPs were characterized by scanning electron microscope, UV-visible spectroscopy and Fourier transform infrared spectroscopy. Batch adsorption studies have shown that removal is dependent upon process parameters like initial concentration, contact time, pH and adsorbent dosage. The adsorption data obtained from batch studies at optimized conditions have been subjected to Freundlich and Langmuir isotherm studies. The pseudo-first-order and pseudo-second-order kinetic models were also applied to the experimental data. Phenol was effectively (90.0 +/- A 0.8 %) removed from the aqueous solution using alginate-stabilized AuNPs beads as the adsorption process. Desorption studies were made to elucidate recovery of the adsorbate and adsorbent for the economic competitiveness of the removal system. The alginate-stabilized AgNPs and AuNPs beads were found to be good adsorbents for adsorption of phenol from the aqueous solution

Microwave synthesis of polymer coated silver nanoparticles by glucose as reducing agent

821-824Silver nanoparticles have been prepared by the reduction of silver nitrate using glucose as reducing agent and polyvinylpyrrolidone as stabilizing agent and characterized by transmission electron microscopy and UV-visible spectroscopy. TEM images show the average size of silver nanoparticles to be 11 nm. Various optimizing parameters such as effects of silver nitrate concentration, glucose concentration and microwave irradiation time are also described

Determination of cadmium(II) with 5-Br-PADAP in the presence of CPC and HDPBA

1408-14122-(5-Bromo-2-pyridylazo)-5-diethylaminophenol (5- Br-PADAP), a trihydroxy phenyl dye and N-hydroxy-N,N ' diphenylbenzomidine (HDPBA), a reported extractant, in presence of a cationic surfactant (CPC) have been used for the spectrophotometric determination of cadmium(II). The Cd(II)CPC-(5-Br-PADAP) red coloured complex formed in aqueous medium has been extracted with N-hydroxy-N,N ' diphenylbenzomidine in dichloromethane in the pH range 8.6-10.6. This extracted complex shows maximum absorbance at λmax= 560 nm against reagent blank with molar absorptivity of 9.5×104 dm3 mol-1 cm-1. The detection limit of the method is 0.01μg ml-1. The relative standard deviation (RSD, n= 10) for solutions containing 0.40 μg ml-1 Cd(II) is 1.6%. The system obeys Beer's law in the range 0.05-1.0μg ml-l. The effect of foreign ions and other experimental variables have been studied. Cd(II) has been successfully determined in standard, environmental and biological samples using the present method

Extraction of chloroplatinate(II)– 2-[(5-bromo-2-pyridylazo)]-5-diethylaminophenol-(TX-100)-<i style="">N</i>-hydroxy-<i style="">N,N’</i>- diphenylbenzamidine complex

138-143A sensitive and selective spectrophotometric method, developed for the determination of trace amounts of platinum, is based on the formation of platinum as a mixed complex with 2-[(5-bromo-2-pyridylazo)]-5-diethylaminophenol (5-Br-PADAP) and TX-100 or triton X-100 (Polyethylene-di-isobutyl-glycol-ether) from 0.1M SnCl2 in to HCl and extraction with N-hydroxy-N,N’-diphenylbenzamidine (HDPBA) in dichloromethane. The violet coloured Pt(II)- 5-Br-PADAP-(TX-100)–HDPBA complex in dichloromethane shows maximum absorbance at 575 nm with molar absorptivity value of 6.0x104 dm3/mol/cm. The repeatability of the method was checked by finding relative standard deviation (RSD, n=10) value for solutions each containing 1.5 g/cm2 Pt(II) and the RSD value of the method was found to be 1.5%. The system obeyed Beer’s law up to 2.1 mg/cm2 of platinum and the detection limit of the method is 20 ng/cm2 on a three times the standard deviation of the blank absorbance basis. High concentration of foreign ions, with the exception of palladium, does not interfere with the determination of platinum. The proposed method has been applied for determination of platinum in automobile exhaust sample, soil and vegetation samples

Determination of free and total zinc using 2-[(5-bromo-2-pyridylazo)]- 5-diethylaminophenol in mixed surfactant medium

733-736A simple and sensitive spectrophotometric method for chemical fractionation and determination of zinc in cosmetics and pharmaceuticals is described based on the formation or red coloured species of Zn(II) with 2-[(5-bromo-2-pyridylazo)]-5-diethylaminophenol (5-Br-PADAP) and mixed surfactants (TX-100 and Brij-35) in the pH range 8.2- 10.5. The red coloured Zn(II)-5-Br-PADAP-(TX-100+Brij-35) complex in aqueous medium shows maximum absorbance at 550 mm with molar absorptivity of 1.60105 dm3 mol-1  cm-l. The detection limit or the method is 6 ng  Zn(II)/cm2 and obeys Beer's law up to 0.4 µg Zn(II)/cm2 in aqueous phase. Relative standard deviation for ten determinations for solution containing 0.2 µg Zn(II)/cm2 is 1.5%. The validity of the method has been satisfactorily examined for the determination of zinc (free and total) in cosmetics and pharmaceutical formulating samples manufactured in India, with RSD value from actual analyte content ranging between 2.1 and 2.7% for cosmetics and between 1.9 and 2.8 % for pharmaceutical formulations. </span