A simple, precise, inexpensive and reproducible spectrophotometric method was investigated for the determination of chromium ion (III) in aqueous media, this method based on the formation of a complex between chromium...A simple, precise, inexpensive and reproducible spectrophotometric method was investigated for the determination of chromium ion (III) in aqueous media, this method based on the formation of a complex between chromium ion (III) and ninhydrin, a deep greenish-violet colored product in the presence of potassium hydroxide was obtained. The absorption of this product was measured at λ<sub>max</sub> = 375 nm. The reaction proceeds quantitatively at room temperature. The linear calibration curve was constructed over range of (4.8 × 10<sup>-4</sup> - 1.6 × 10<sup>-2</sup>) mol/L of chromium ions with molar absorptivity of 2.90 × 10<sup>2</sup> and correlation coefficient R<sup>2</sup> = 0.9989. The calculated Sandell’s sensitivity value is 0.179 μg/cm<sup>2</sup>, the limits of detection (LOD) and the limit of quantification (LOQ) are found to be 3.74 × 10<sup>-5</sup> and 1.24 × 10<sup>-4</sup> mol/L, respectively. The method was successfully applied for determination of the chromium ion in aqueous solution. The stoichiometry of the reactions was determined molar combining ratio of 1:2 between chromium and ninhydrin.展开更多
The effect of cationic micelles of cetyltrimethylammonium bromide (CTAB) on the interaction of chromium dipeptide complex ([Cr(Ⅲ)-Gly-Gly]2+) with ninhydrin under varying conditions has been investigated. The rates o...The effect of cationic micelles of cetyltrimethylammonium bromide (CTAB) on the interaction of chromium dipeptide complex ([Cr(Ⅲ)-Gly-Gly]2+) with ninhydrin under varying conditions has been investigated. The rates of the reaction were determined in both water and surfactant micelles in the absence and presence of various organic and inorganic salts at 70 ℃ and pH 5.0. The reaction followed first- and fractional-order kinetics with respect to [Cr(Ⅲ)- Gly-Gly2+] and [ninhydrin]. Increase in the total concentration of CTAB from 0 to 40×10-3 mol·dm-3 resulted in an increase in the pseudo-first-order rate constant (kψ) by a factor of ca 3. Quantitative kinetic analysis of kψ-[CTAB] data was performed on the basis of the pseudo-phase model of the micelles. As added salts induce structural changes in micellar systems that may modify the substrate-surfactant interactions, the effect of some inorganic (NaBr, NaCl, Na2SO4) and organic (NaBenz, NaSal, NaTos) salts on the rate was also explored. It was found that the tightly bound counterions (derived from organic salts) were the most effective.展开更多
An efficient synthesis of hydroindeno[1,2-b]indoles is described via three-component reaction of ninhydrin and cycloalkan-1,3-dione in the presence of primary amines in water as the green solvent in excellent yield.
It is extremely difficult to develop fingerprints from the surface of currency.There are studies reporting that the high vacuum metal deposition(VMD)method can be used to detect fingerprints on certain types of curren...It is extremely difficult to develop fingerprints from the surface of currency.There are studies reporting that the high vacuum metal deposition(VMD)method can be used to detect fingerprints on certain types of currency notes.Both VMD and 1,2-indandione/ninhydrin techniques are employed to visualize latent fingermarks on porous surfaces,such as paper.The current study explores whether the VMD method or 1,2-indandione/ninhydrin reagent method is more effective in the development of fingerprints on remninbi(RMB).Uncirculated,circulated,and water-exposed RMB was utilized in this study,along with five donors who ranged in their age and potential to leave fingermarks.Samples were aged for a determined period(for uncirculated and circulated RMB,times were 1,3,5,10,and 35 days;for watei^exposed RMB,exposure time was 1 day)and then treated with VMD and 1,2-indandione/ninhydrin.The results suggested that the 1,2-indandione/ninhydrin reagent yielded a better effect for both circulated and uncirculated RMB.For the RMB exposed to water,VMD performed better and gave limited results in terms of fingerprint development,which could serve as a reference for actual forensic cases.展开更多
文摘A simple, precise, inexpensive and reproducible spectrophotometric method was investigated for the determination of chromium ion (III) in aqueous media, this method based on the formation of a complex between chromium ion (III) and ninhydrin, a deep greenish-violet colored product in the presence of potassium hydroxide was obtained. The absorption of this product was measured at λ<sub>max</sub> = 375 nm. The reaction proceeds quantitatively at room temperature. The linear calibration curve was constructed over range of (4.8 × 10<sup>-4</sup> - 1.6 × 10<sup>-2</sup>) mol/L of chromium ions with molar absorptivity of 2.90 × 10<sup>2</sup> and correlation coefficient R<sup>2</sup> = 0.9989. The calculated Sandell’s sensitivity value is 0.179 μg/cm<sup>2</sup>, the limits of detection (LOD) and the limit of quantification (LOQ) are found to be 3.74 × 10<sup>-5</sup> and 1.24 × 10<sup>-4</sup> mol/L, respectively. The method was successfully applied for determination of the chromium ion in aqueous solution. The stoichiometry of the reactions was determined molar combining ratio of 1:2 between chromium and ninhydrin.
文摘The effect of cationic micelles of cetyltrimethylammonium bromide (CTAB) on the interaction of chromium dipeptide complex ([Cr(Ⅲ)-Gly-Gly]2+) with ninhydrin under varying conditions has been investigated. The rates of the reaction were determined in both water and surfactant micelles in the absence and presence of various organic and inorganic salts at 70 ℃ and pH 5.0. The reaction followed first- and fractional-order kinetics with respect to [Cr(Ⅲ)- Gly-Gly2+] and [ninhydrin]. Increase in the total concentration of CTAB from 0 to 40×10-3 mol·dm-3 resulted in an increase in the pseudo-first-order rate constant (kψ) by a factor of ca 3. Quantitative kinetic analysis of kψ-[CTAB] data was performed on the basis of the pseudo-phase model of the micelles. As added salts induce structural changes in micellar systems that may modify the substrate-surfactant interactions, the effect of some inorganic (NaBr, NaCl, Na2SO4) and organic (NaBenz, NaSal, NaTos) salts on the rate was also explored. It was found that the tightly bound counterions (derived from organic salts) were the most effective.
基金financial and spiritual support from Research Council of Gonbad Kavous University
文摘An efficient synthesis of hydroindeno[1,2-b]indoles is described via three-component reaction of ninhydrin and cycloalkan-1,3-dione in the presence of primary amines in water as the green solvent in excellent yield.
基金Source of support in the form of grants:Operation Expenses for Universities'Basic Scientific Research in 2016 ofPPSUC(No.2016JKF01102).
文摘It is extremely difficult to develop fingerprints from the surface of currency.There are studies reporting that the high vacuum metal deposition(VMD)method can be used to detect fingerprints on certain types of currency notes.Both VMD and 1,2-indandione/ninhydrin techniques are employed to visualize latent fingermarks on porous surfaces,such as paper.The current study explores whether the VMD method or 1,2-indandione/ninhydrin reagent method is more effective in the development of fingerprints on remninbi(RMB).Uncirculated,circulated,and water-exposed RMB was utilized in this study,along with five donors who ranged in their age and potential to leave fingermarks.Samples were aged for a determined period(for uncirculated and circulated RMB,times were 1,3,5,10,and 35 days;for watei^exposed RMB,exposure time was 1 day)and then treated with VMD and 1,2-indandione/ninhydrin.The results suggested that the 1,2-indandione/ninhydrin reagent yielded a better effect for both circulated and uncirculated RMB.For the RMB exposed to water,VMD performed better and gave limited results in terms of fingerprint development,which could serve as a reference for actual forensic cases.
基金National Natural Science Foundation of the People’s Republic of China(32201935,21773080,22011540378)Education Department of Jilin Province(JJKH20211127KJ)+1 种基金the Development Program of the Science and Technology of Jilin Province(20190701003GH)the Interdisciplinary Integration and Innovation Project of JLU(JLUX4JC2021Q211)。
