CHINESE JOURNAL OF CATALYSIS
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2014
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IF 1.552
Xianfeng Fu,Jianyong Zheng,Xiangxian Ying,Hongde Yan,Zhao Wang
A novel ultraviolet (UV) spectrophotometric method for evaluating lipase transesterification activity in organic solvents is described. The model reaction was lipase-catalyzed transesterification between p -nitrophenyl palmitate (pNPP) and n -butanol in n -hexane at 30 °C. The conversion of pNPP to p -nitrophenol was monitored by measuring UV absorbance changes at 310 nm. Seven commercial lipases were tested using this method, and the results were similar to those obtained using gas chromatography . The UV spectrophotometric method was used to investigate the kinetics of the Lipozyme TL IM-catalyzed reaction of pNPP, and the correlation between synthetic activity and biocatalyst concentration was determined. The method was also used to investigate the Lipozyme TL IM-catalyzed transesterification properties, namely solvent effect, acyl acceptor specificity, alcohol tolerance, optimum reaction temperature, and thermostability.
研究领域:
生物化学
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酶工程
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DOI
高影响因子
Journal of Analysis and Testing
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2022
·Vol. 7
·期 2
·157-162
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IF 0
Gao Su,Ye Ming-Liang,Ma Rui,Liu Ai-Rong,Gao Hong-Wen
Based on the Mg 2 + complexation with acid chrome blue K (ACBK) at pH 10.2, an automatic system was designed to determine total hardness of water. The system consists of a vector colorimeter, a multi-channel sampling pump and both reagents A and B. Two kinds of reagent solutions were prepared and used in this system, i.e., ammoniacal buffer and ACBK—disodium magnesium EDTA solutions. The experimental results of the standard solutions containing 2 and 3 mg/L of total hardness showed that the relative standard deviations (RSDs) were 1.9% and 2.2%, respectively, and the limit of detection (LOD) was only 0.035 mg/L. The detection of four natural water samples showed that the recoveries were between 85.0% and 108.6%, consistent with those obtained by ICP-AES method.
研究领域:
分析化学
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环境科学
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产品关联
DOI
SPECTROSCOPY LETTERS
·
2025
·
IF 1.6
Jin Dangqin,Zhou Hui,Xiao Jiali,Gao Qin,Gong Aiqin
This study presents the development and validation of UV-spectrophotometry methods for the quantification of organophosphorus pesticide residues in fruits and vegetables based on solid phase extraction and the principle of enzyme inhibition of catalase. A silica gel modified with 3,3 ‘- dodecyl-1,1’ - di-1-vinylimidazolium bromide ionic liquid (Poly - (3,3 ‘- dodecane-1,1’ - bis-1-vinylimidazolium dibromide modified silica), Poly (DBVD) - Sil, is used as a solid-phase extraction adsorbent. At the same time, based on the principle of enzyme inhibition of catalase, bovine liver catalase was screened as the enzyme solution, and a rapid detection method for profenofos residue was established by solid-phase extraction UV-spectrophotometry by optimizing the reaction conditions. That CAT inhibited the oxidation of MB by H2O2, limited MB fading, and the degree of absorbance recovery was related to CAT activity. Profenofos has a significant inhibitory effect on catalase, with a decrease in absorbance values. The natural logarithm of profenofos is linearly related to the enzyme activity inhibition rate within the range of 0.001-5.0 mg/L, the linear regression equation is y = 0.0509x + 0.4341, with R2=0.9968, the detection limit (3s/k) is 3.1 × 10−4 mg/L. A standard recovery rate of 95.3% to 104.2% for profenofos. The results showed the method is simple, fast, precise, accurate, and has a low detection limit, meeting the needs of rapid detection of profenofos residues in fruits and vegetables.
研究领域:
分析化学
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食品科学
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环境科学
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产品关联
DOI
高影响因子
SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
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2020
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IF 3.232
Jin Yang,Yan Cao,Naidong Zhang
A method was developed that used hydroxylamine hydrochloride as a probe in a superoxide anion radical-generating visible light system for determining superoxide anion radicals. An Azure I solution with hydroxylamine hydrochloride was illuminated, after which a ferric iron solution was added to the sample solution and the remaining hydroxylamine hydrochloride in solution reduced from ferric to ferrous ions. Then, 1,10-phenanthroline solution was added and spectrophotometrically measured at 510 nm, which indirectly indicated the hydroxylamine hydrochloride content. The yields of superoxide anion radicals were indirectly expressed by the hydroxylamine hydrochloride decrement. Under optimal experimental conditions, the linear range was 0.0–1.5 × 10 −5 M and the limit of detection and limit of quantification were obtained to be 8.37 × 10 −7 and 2.54 × 10 −6 M with an R 2 of 0.9993. The method was simple and feasible and could be used for the stable measurement of superoxide anion radicals produced by photosensitizers that produce color under acidic conditions in visible light systems.
研究领域:
生物化学
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分析化学
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产品关联
DOI
PubMed
高影响因子
MOLECULES
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2019
·Vol. 24
·期 4
·663
·
IF 3.06
Kai Song,Yejing Wang,Yu Li,Chaoxiang Ding,Rui Cai,Gang Tao,Ping Zhao,Qingyou Xia,Huawei He
Enzymatic activity assays are essential and critical for the study of enzyme kinetics. Adenylate kinase (Adk) plays a fundamental role in cellular energy and nucleotide homeostasis. To date, assays based on different principles have been used for the determination of Adk activity. Here, we show a spectrophotometric analysis technique to determine Adk activity with bromothymol blue as a pH indicator. We analyzed the effects of substrates and the pH indicator on the assay using orthogonal design and then established the most optimal assay for Adk activity. Subsequently, we evaluated the thermostability of Adk and the inhibitory effect of KCl on Adk activity with this assay. Our results show that this assay is simple, rapid, and precise. It shows great potential as an alternative to the conventional Adk activity assay. Our results also suggest that orthogonal design is an effective approach, which is very suitable for the optimization of complex enzyme reaction conditions.Keywords:enzymatic activity assay;adenylate kinase;spectrophotometry;orthogonal experiment;bromothymol blue
研究领域:
生物化学
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分子生物学
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产品关联
DOI
PubMed
高影响因子
Analytical Methods
·
2018
·Vol. 10
·期 28
·3470-3474
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IF 2.073
Chen Wang,Rui Chen,Ruyu Zhang,Naidong Zhang
A rapid, simple, and sensitive spectrophotometric method for sulfate radical determination in aqueous solutions was developed, employing the reaction between sulfate radicals and cerium(III) sulfate to quantitatively generate cerium(IV) sulfate. The relative concentrations of sulfate radicals were evaluated through Ce4+ quantitation by UV-spectrophotometry. Factors affecting this method, including the concentration of cerium sulfate concentration, reaction time, pH, and inorganic anions, were investigated. Finally, using this method, the rate of sulfate radical generation by photolysis of peroxydisulfate under different light sources was studied.
研究领域:
分析化学
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环境科学
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产品关联
DOI
高影响因子
CEREAL CHEMISTRY
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2023
·Vol. 100
·期 5
·1106-1113
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IF 2.4
Yuhang Wan,Xinyu Yuan,Jia Liu,Ding Zhang,Zhengyong Zhang,Min Sha
Background and Objectives Targeting the problems, like various residual pesticides, the high interference of sample matrix and the slow detection speed, this work studied the rapid screening method of multipesticide residues in rice by taking bensulfuron-methyl, propanil and cypermethrin as examples. Findings Rice matrix solution was obtained by using the improved QuEChERS method, matrix standard solution, and solvent standard solution were prepared to obtain the linear range and matrix effect of each pesticide. QuEChERS method could rapidly pretreat samples, and the matrix effect was soft, with matrix effect values lower than 16%. Mixed solutions of the three pesticides in four combinations were prepared within the linear range. The type of pesticides in rice was determined by support vector machine (SVM), and the pesticide concentration was predicted by partial least square regression (PLSR). SVM provided a supervised identification method for pesticide residues, making the recognition accuracy higher than 90%. The error of PLSR in predicting pesticide concentration was lower than 5.36%. Conclusions UV spectroscopy had fast test speed, so the combination of QuEChERS and UV spectroscopy could improve the efficiency of analysis. SVM combined with PLSR could preliminarily determine the type of pesticides in rice sample, and then accurately predict the concentration of pesticides. Significance and Novelty The QuEChERS sample pretreatment technology and UV spectroscopy in combination with chemometrics was expected to be a new technology for rapid detection of pesticide residues in samples.
研究领域:
分析化学
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食品科学
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农学
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DOI
高影响因子
CHEMICAL PHYSICS LETTERS
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2023
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IF 2.8
Huijuan Shi,Yunzhi Tang,Yuhui Tan,Zhen Sun
Due to the decomposition, condensation, and invalidation of organic additives in acid copper plating solution, it is hard to identify the effective concentration of additives, which causes difficulties in the prediction and grasping of the electroplating effect. To solve this problem, this paper established the linear relationship between absorbency and the concentration of organic additives based on the principle of ultraviolet spectrophotometry and the luminescence mechanism of the chromogenic agent and three organic additives after eliminating the interference of copper and hydrogen ions in the plating solution. The concentrations of polyethylene glycol (PEG), bis-(sodium sulfopropyl)-disulfide(SPS), and gelatin in the solution were analyzed quantitatively according to Law of Lambert-Beer. According to the results, the linear relationship between PEG’s mass concentration and absorbency can be described as y = 0.01057 + 0.01372x, with a linear correlation of 0.9982, a relative error of about 0.56%-3.7%, and a minimum detection limit of 1 mg/L. The method adopted for detecting the SPS content records a relative error of around 0.817%-4.202% with the minimum detection limit of 2 μmol/L. The linear relationship between gelatin concentration and absorbancy is expressed as y = 0.02165x + 0.00932, in which the linear correlation r = 0.9906.
研究领域:
化学工程
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分析化学
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产品关联
DOI
高影响因子
ACS Sustainable Chemistry & Engineering
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2025
·
IF 7.3
Yulin Wang,Xiaoning Wei,Yajie Yue,Qingrong Peng,Xianzhao Zhang,Agnieszka Brandt-Talbot,Jiajun Han,Xu Jing
This study presents a rapid method for detecting organophosphate insecticide residues using emulsive liquid–liquid microextraction combined with ultraviolet spectrophotometry (ELLME-UV). By employing the conductor-like screening model for real solvents to predict the chemical potentials of 17 extractants, oleic acid was identified as the optimal extractant owing to its high binding affinity, eliminating the need for trial-and-error selection. In the ELLME-UV process, an oil-in-water emulsion was formed by combining oleic acid with an aqueous alkaline solution, followed by sample addition, allowing rapid extraction within 1 min. Then, citric acid was added to induce rapid demulsification and separate oleic acid from the sample within 10 s, eliminating the need for a time-consuming centrifugation step. Under alkaline conditions, p-nitrophenol, prepared from parathion-methyl, exhibited a strong UV signal, and it was efficiently transferred to the separated oleic acid phase, enabling its detection in a 96-well plate within 1 min. Using pH adjustment, oleic acid was successfully used as an extractant, achieving emulsification and demulsification in the sample. By integrating extraction and derivatization into a single step, the proposed method simplifies sample pretreatment and detection, increasing the overall efficiency. The ELLME-UV method was successfully applied to various matrices, and recoveries ranged from 85.3 to 102.9%, with relative standard deviations of 0.6–4.5%, demonstrating its accuracy and reproducibility. These results highlight the potential of the proposed method as a rapid, simple, and environmentally sustainable solution for detecting organophosphate insecticide residues. This study highlights the environmentally friendly properties of oleic acid, which has historically been difficult to emulsify.
研究领域:
分析化学
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环境科学
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农药残留检测
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产品关联
DOI
高影响因子
SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
·
2025
·
IF 4.6
Xiaojing Yang,Tingyi Qiao,Fengping Hou,Nan Dong
Spermidine has emerged as a promising biomarker for the early-stage diagnosis of cancer in humans. A novel extractive spectrophotometric analytical method has been developed for the determination of spermidine in urine samples. This technique leverages the selective extraction of spermidine from complex matrices using a cucurbit[7]uril-truxene derivative (Q[7]-Cs-Tr) as a fluorescent extractant. The Q[7]-Cs-Tr forms a stable host-guest complex with spermidine, facilitating its extraction from the aqueous phase to the organic phase. The formation of this complex results in a decrease in the fluorescence intensity of the Q[7]-Cs-Tr in the organic phase. Key factors influencing extraction efficiency, including the type of dispersed organic solvent, extractant concentration, solution pH, extraction times, and equilibrium time, were thoroughly investigated. The method demonstrated minimal interference from various metal ions, anions, amino acids, and other biogenic amines. It also exhibited a low limit of detection (8.6 nM), excellent linearity (R 2 = 0.9972), and high repeatability (RSD = 2.4 % intra-day, RSD = 3.6 % inter-day). The proposed method was successfully applied to determine spermidine levels in urine samples, yielding satisfactory recoveries ranging from 96.3 % to 103.5 %. Compared to existing methods, this approach is simple, reliable, highly sensitive, and exhibits low interference, making it a potential robust tool for clinical diagnostics.
研究领域:
分析化学
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生物化学
·
临床诊断学
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DOI
PubMed
高影响因子
Pharmacognosy Magazine
·
2010
·
IF 0
Minxia Zheng,Jie Shen,Kai Yang,Songxiang Qian,Sujuan Feng
A simple approach for the rapid determination of polysaccharides in BianTi Soft Extract using spectrophotometry coupled with gas chromatography-mass spectrometry (GC-MS) was developed. The mixed standard solution composed of D-glucose, D-mannose, galactose and D-xylose in different proportions (1.00: 1.01: 0.12: 0.05) was prepared according to the monosaccharide composition analysis of the polysaccharides by GC-MS. The determination of polysaccharides by UV-Vis spectrophotometer was performed after 35-min color reaction, in which 1 ml 5% phenol and 4 ml sulfate was used. The assay of the method validation has shown that the method was stable, reliable and feasible. Furthermore, the proposed method was successfully applied in the preparation procedure of BianTi Soft Extract, selecting out optimal decoction conditions and suitable decoction container. It suggests that the convenient method could be useful for the quality control of BianTi Soft Extract. Meanwhile, it may be an alternative for polysaccharides determination of other formulations.
研究领域:
分析化学
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中药学
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产品关联
DOI
PubMed
JOURNAL OF MOLECULAR LIQUIDS
·
2016
·
IF 2.74
Handi Yin,Zhiguo Hao,Jihua Zhao,Peizhu Zheng,Weiguo Shen
The kinetics of the Diels–Alder (D–A) reactions of N-ethylmaleimide with 2,3-dimethyl-1,3-butadiene and of 9,10-dimethyl-anthracene with diethyl maleate in two critical binary solutions n -tetradecane + dimethyl carbonate and n -nonane + diethyl maleate have been studied by the three-wavelength UV-spectrophotometry. It was found that neither speeding up nor slowing down effect for the first reaction was observed, which obeyed the Griffiths–Wheeler rule; while a very weak slowing down effect was detected for the second reaction, but significantly weaker as compared with the prediction by the Griffiths–Wheeler rule. It was attributed to that only less than 0.002% of diethyl maleate changed to the products during the reaction, hence the concentration of diethyl maleate may be considered as a fixed thermodynamic density in the critical reaction system, resulting in no thermodynamic slowing down being detected.
研究领域:
物理化学
·
反应动力学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）