Food safety problems caused by excessive nitrite addition have been frequently reported and the detection of nitrite in food is particularly important. The standing time during the pretreatment of primary sample has a...Food safety problems caused by excessive nitrite addition have been frequently reported and the detection of nitrite in food is particularly important. The standing time during the pretreatment of primary sample has a great influence on the concentration of nitrite tested by spectrophotometric method. In this context, three kinds of food samples are prepared, including canned mustard, canned fish and home-made pickled water. A series of standing times are placed during the sample pretreatments and the corresponding nitrite contents in these samples are detected by spectrophotometric method based on N-ethylenediamine dihydrochloride. This study aims to find out a reasonable standing time during the pretreatment of food sample, providing influence factor for precise detection of nitrite.展开更多
The complex of molybdenum (VI) with stilbene-2,2’-disulfonic acid-4,4’’bis (azo-1’’)-3’’, 4’’ dioxybenzene (stillbazo) in the presence of a cationic surfactant cetylpyridinium chloride (CPCl) was studied spec...The complex of molybdenum (VI) with stilbene-2,2’-disulfonic acid-4,4’’bis (azo-1’’)-3’’, 4’’ dioxybenzene (stillbazo) in the presence of a cationic surfactant cetylpyridinium chloride (CPCl) was studied spectrophotometrically. It was found that in the presence of CPCl, a mixed-ligand complex with a component ratio of 1:2:4 is formed. The effect of pH, time, temperature, the concentration of reagents, and CPCl in the formation of homogeneous ligand and mixed-ligand complexes were studied. The stability constants (lg<em>β</em><sub><em>k</em></sub> = 86 × 10<sup>8</sup>) and the molar absorption coefficient of the mixed-ligand complex (<em>ε</em><sub><em>к</em></sub> = 11,835) were determined. It was found that Beer’s law is observed at a concentration of 0.05 - 17.00 μg/ml. A method has been developed for the spectrophotometric determination of molybdenum (VI) in complex industrial facilities.展开更多
Cadmium toxicity in wastewater is a rising concern due to industries like batteries,metallurgy,electroplating,plastic stabilizers,and pigments.The quantitative detection of Cd^(2+)and its remediation from wastewater s...Cadmium toxicity in wastewater is a rising concern due to industries like batteries,metallurgy,electroplating,plastic stabilizers,and pigments.The quantitative detection of Cd^(2+)and its remediation from wastewater samples are of major concern from an environmental point of view.In the present work,an effective spectrophotometric method has been reported using 5,7-dibromo-8-hydroxyquinoline(DBHQ)as a complexing agent for Cd^(2+).This method has advantages like using recyclable,less toxic solvents and easy sample preparation.The limit of detection,limit of quantification,and sensitivity of the proposed method were found to be 33.30,36.70 mg L^(−1),and 2×10^(−3),respectively.The DBHQ method was validated using atomic absorption spectroscopy,and the recovery percentage was more than 98%.These results indicate that DBHQ can be effectively used for monitoring Cd^(2+)in aqueous systems.The method developed was further employed for monitoring Cd^(2+)adsorption on calcium alginate(AL)hydrogels.Batch adsorption studies were done to optimize parameters of Cd^(2+)removal using AL hydrogels,and the data obtained were used for kinetic and thermodynamic studies.Kinetic studies indicated that the pseudo-first-order model showed better fitting,and thermodynamic studies showed Freundlich-like adsorption.The maximum adsorption capacity of Cd^(2+)on AL hydrogels was found to be 56.45 mg g^(−1).The validation studies of DBHQ were performed using statistical analysis methods like t-tests and one-way variance.展开更多
文摘Food safety problems caused by excessive nitrite addition have been frequently reported and the detection of nitrite in food is particularly important. The standing time during the pretreatment of primary sample has a great influence on the concentration of nitrite tested by spectrophotometric method. In this context, three kinds of food samples are prepared, including canned mustard, canned fish and home-made pickled water. A series of standing times are placed during the sample pretreatments and the corresponding nitrite contents in these samples are detected by spectrophotometric method based on N-ethylenediamine dihydrochloride. This study aims to find out a reasonable standing time during the pretreatment of food sample, providing influence factor for precise detection of nitrite.
文摘The complex of molybdenum (VI) with stilbene-2,2’-disulfonic acid-4,4’’bis (azo-1’’)-3’’, 4’’ dioxybenzene (stillbazo) in the presence of a cationic surfactant cetylpyridinium chloride (CPCl) was studied spectrophotometrically. It was found that in the presence of CPCl, a mixed-ligand complex with a component ratio of 1:2:4 is formed. The effect of pH, time, temperature, the concentration of reagents, and CPCl in the formation of homogeneous ligand and mixed-ligand complexes were studied. The stability constants (lg<em>β</em><sub><em>k</em></sub> = 86 × 10<sup>8</sup>) and the molar absorption coefficient of the mixed-ligand complex (<em>ε</em><sub><em>к</em></sub> = 11,835) were determined. It was found that Beer’s law is observed at a concentration of 0.05 - 17.00 μg/ml. A method has been developed for the spectrophotometric determination of molybdenum (VI) in complex industrial facilities.
文摘Cadmium toxicity in wastewater is a rising concern due to industries like batteries,metallurgy,electroplating,plastic stabilizers,and pigments.The quantitative detection of Cd^(2+)and its remediation from wastewater samples are of major concern from an environmental point of view.In the present work,an effective spectrophotometric method has been reported using 5,7-dibromo-8-hydroxyquinoline(DBHQ)as a complexing agent for Cd^(2+).This method has advantages like using recyclable,less toxic solvents and easy sample preparation.The limit of detection,limit of quantification,and sensitivity of the proposed method were found to be 33.30,36.70 mg L^(−1),and 2×10^(−3),respectively.The DBHQ method was validated using atomic absorption spectroscopy,and the recovery percentage was more than 98%.These results indicate that DBHQ can be effectively used for monitoring Cd^(2+)in aqueous systems.The method developed was further employed for monitoring Cd^(2+)adsorption on calcium alginate(AL)hydrogels.Batch adsorption studies were done to optimize parameters of Cd^(2+)removal using AL hydrogels,and the data obtained were used for kinetic and thermodynamic studies.Kinetic studies indicated that the pseudo-first-order model showed better fitting,and thermodynamic studies showed Freundlich-like adsorption.The maximum adsorption capacity of Cd^(2+)on AL hydrogels was found to be 56.45 mg g^(−1).The validation studies of DBHQ were performed using statistical analysis methods like t-tests and one-way variance.
