EUROPEAN FOOD RESEARCH AND TECHNOLOGY
·
2014
·Vol. 238
·期 5
·889-894
·
IF 1.387
Zhu Jinghui,Li Chunyan,Liu Shaopu,Liu Zhongfang,Yang Jidong,Tian Jing,Hu Xiaoli
A non-diazotization-coupling reaction-based colorimetric method was developed and validated for the determination of nitrite in tap water and milk samples. Under acidic condition, nitrite could selectively react with pyrrole, resulting in the emerging of a new absorption peak at 509 nm and a distinct color change from clear to red, with which the concentration of nitrite can be determined indirectly. Excellent linear range was achieved from 0.72 to 40.0 μmol L −1 with a detection limit of 0.22 μmol L −1 . The detection limit was lower than or comparable to most of the recently published methods. The experimental conditions were optimized, and effects of coexisting substances were evaluated, and the results showed excellent priority since a certain amount of other anions, including SO 3
− , SeO 3
− and other acid radicals, would not interfere with the measurement. We highlighted the simplicity and efficiency of this method as no diazotization-coupling procedure and toxic aniline were involved. Determination of nitrite in tap water and milk samples was performed.
研究领域:
分析化学
·
环境科学
·
食品科学
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产品关联
DOI
高影响因子
SENSORS AND ACTUATORS B-CHEMICAL
·
2023
·
IF 8.4
Chang Liu,Zihao Deng,Yanan Deng,Kaijing Yuan,Miao Hu,Lili Yuan,Jianmei Zou,Jinfang Nie,Yun Zhang
This work describes a new class of universal nanoprobe-free colorimetric assay with Tyndall effect (TE) signaling for amplified detection of nanomolar heavy metal ions based on analyte-triggered multi-component complexation. In the presence of NH 2 OH·HCl, Cu 2+ (model analyte) is reduced to Cu + which in turn reacts with KSCN and CHClN 2 O 3 to form colloidal three-component complexation particles unexpectedly producing an enhanced TE signal with the aid of a 635 nm laser pointer . The results show that the developed method could detect Cu 2+ in a linear concentration range of 156 nM ∼ 120 µM with a limit of detection (LOD) of ∼38 nM (3σ) using a smartphone for quantitative readout. The generality of the new equipment-free strategy was demonstrated well with selective detection of Cd 2+ as the second model analyte with a LOD down to ∼1.27 nM where KI and CHClN 2 O 3 were adopted as the three-component complexation reagents. In addition, satisfying recovery results obtained from analysis of Cu 2+ and Cd 2+ in several polluted real water samples ranged from 93.1% to 104.67% and 93.21–101.85%, respectively. To the best of our knowledge, this may be the first report of nanoprobe-free TE-based colorimetric assay based on multi-component complexation.
研究领域:
分析化学
·
环境科学
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产品关联
DOI
高影响因子
MICROCHIMICA ACTA
·
2019
·Vol. 186
·期 8
·1-7
·
IF 5.479
Li Younan,Luo Guoyan,Qing Zhihe,Li Xiaoxuan,Zou Zhen,Yang Ronghua
A colorimetric and visual assay is described for the herbicide aminotriazole (ATZ). It is based on the etching of gold nanorods (AuNRs) by iodine which is formed on oxidation of iodide via H 2 O 2 . Longitudinal etching of the AuNRs occurs quickly and is accompanied by a color change from dark blue to red. In the absence of ATZ and the presence of active catalase (CAT), H 2 O 2 is quickly decomposed into water, and the AuNRs will not be etched. In the presence of ATZ, CAT is partially deactivated, and this affects the amount of available H 2 O 2 and, consequently, of the iodine. Hence, the color is significantly changed. The color changes can be easily detected with bare eyes. The assay has a linear response in the 5 to 70 μM concentration range, with a detection limit of 1.3 μM and high selectivity for ATZ. It was applied to the determination of ATZ in water and food samples.
A multicolor colorimetric method is developed for aminotriazole (ATZ) detection based on catalase (CAT) deactivation-dependent longitudinal etching of gold nanorods (AuNRs). The color signals can be visually identified. Good detection performances and capability for evaluating ATZ level in water and food samples is demonstrated.
研究领域:
分析化学
·
环境科学
·
纳米技术
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产品关联
DOI
PubMed
高影响因子
SENSORS AND ACTUATORS B-CHEMICAL
·
2024
·
IF 8
Tianfei Qi,Ruonan Jia,Linbo Zhang,Guanyu Li,Xuefeng Wei,Jianting Ye,Ruilian Qi,Haiyuan Chen
Self-reporting corrosion protection coatings offer effective means to detect potential failures in advance, allowing for timely maintenance and extending the lifespan of metal materials. However, there currently remains a challenge in developing techniques capable of concurrently monitoring coating damage and metal corrosion throughout a procedure. Herein, N-CDs/Fe 3 O 4 hybrid nanoparticles with high peroxidase-like activity were fabricated through a two-step hydrothermal process which exhibit superior affinity (K m =1.2 mM) towards H 2 O 2 than HRP and effectively turn-on the color of TMB . Combined with the excellent responsiveness towards 8-HQ and the strict linear dependent relationships towards Fe 3+ (ranging from 0.75 to 15.15 μM), a novel colorimetric assay is established to not only turn on the signals to report the appearance of damage, but additionally switch the colors of TMB system to reveal the possible crack propagation and metal corrosion underneath. Moreover, the pre-existing corrosion, characterized by higher Fe 3+ concentration, is successfully indicated according to the color intensity enhancement compared with pristine metal sheet. Notably, such a multifunctional colorimetric assay enables the real-time and visual monitoring coating damage and metal corrosion simply through a Python program integrated into smartphones, serving as a promising strategy for promptly alerting of potential structural failures.
研究领域:
材料科学
·
腐蚀科学
·
分析化学
·
传感器与执行器
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产品关联
DOI
高影响因子
ANALYTICAL CHEMISTRY
·
2019
·
IF 6.35
Jiahui Zhao,Shuang Wang,Shasha Lu,Guoyong Liu,Jian Sun,Xiurong Yang
Alkaline phosphatase (ALP) usually acts as a signal transmitter in enzyme-linked immunosorbent assay (ELISA); therefore, developing an attractive ALP activity assay, especially using a preferable substrate, would help improve the efficiency and convenience of ELISA in practical applications. Herein we have first prepared an original and creative substrate, named m-hydroxyphenyl phosphate sodium salt (m-HPP), with a desirable dephosphorylation site for ALP. On the basis of the ALP-catalyzed hydrolysis of m-HPP to resorcinol and its subsequent specific nucleophilic reaction with dopamine, we have exploited a fluorometric and colorimetric dual-readout ALP activity assay and ALP-based ELISA system. Under the employed experimental conditions, highly sensitive and specific assay of ALP and cardiac troponin I (cTnI) has been accomplished in a straightforward way. Furthermore, the commendable sensing performance of our proposed ELISA in the determination of the cTnI level in diluted human serum unambiguously illustrates great potential in the early diagnosis of acute myocardial infarction.
研究领域:
生物化学
·
分析化学
·
医学诊断
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ANALYTICAL CHEMISTRY
·
2020
·
IF 6.785
Chuanxia Chen,Dan Zhao,Bo Wang,Pengjuan Ni,Yuanyuan Jiang,Chenghui Zhang,Fan Yang,Yizhong Lu,Jian Sun
Enzyme-triggered in situ chromogenic and/or fluorogenic reactions under accessible conditions are significant for developing enzyme activity and related spectroscopic assays. Here, we describe a facile one-pot synthetic strategy to prepare silicon-containing nanoparticles with yellow-green fluorescence and orange-red color by mixing N-[3-(trimethoxysilyl)propyl]ethylenediamine and p-aminophenol (AP) in aqueous solution at a mild temperature. Encouraged by the AP-regulated simple synthetic procedure and the generation of AP from alkaline phosphatase (ALP)-catalyzed hydrolysis of 4-aminophenol phosphate (APP), a fluorometric and colorimetric dual-readout ALP activity assay can be rationally envisioned and developed by employing APP as the substrate. In the wake of the good analytical performance of such ALP activity assay and its successful combination with enzyme-linked immunosorbent assay (ELISA), corresponding fluorometric and colorimetric dual-readout ALP-based ELISA has been constructed for highly sensitive and quantitative determination of human prostate-specific antigen (PSA), the key biomarker of prostate cancer in human serum. The convincing performance in evaluating the PSA level in serologic tests unambiguously reveals the great potential of our proposed fluorometric and colorimetric dual-channel immunoassay in early clinical diagnosis by monitoring disease biomarkers.
研究领域:
生物化学
·
纳米技术
·
分析化学
·
医学诊断
✓ 已验证
产品关联
DOI
PubMed
高影响因子
MICROCHIMICA ACTA
·
2020
·Vol. 187
·期 10
·1-9
·
IF 6.232
Wei Shengnan,Li Juan,He Jingya,Zhao Wei,Wang Feng,Song Xiuling,Xu Kun,Wang Juan,Zhao Chao
A rapid and sensitive colorimetric assay is described for Salmonella typhimurium ( S. typhimurium ) detection using urea/phenol red impregnated test paper. Aptamer-modified Fe 3 O 4 @Ag multifunctional hybrid nanoprobes (apt-Fe 3 O 4 @Ag NPs) were used to specifically captured S. typhimurium ; the nanoprobes were quickly etched by H 2 O 2 to form Ag + . The generated Ag + can inhibit the urease-catalyzed hydrolysis reaction of urea to produce NH 4 + . Consequently, the as-prepared test paper displayed a yellow color. In the presence of S. typhimurium , the target bacteria can cause aggregation of apt-Fe 3 O 4 @Ag NPs, and the deposited Ag on the nanoprobe’s surface is shielded against H 2 O 2 -induced oxidative decomposition leading to reduced Ag + production. The catalytic activity of urease cannot be inhibited completely by inadequate amount of Ag + . An obvious color change from yellow to pink can be monitored directly using our test paper as a result of increased NH 4 + . The entire assay procedure could be completed within 1 h. A limit of detection of 48 cfu/mL is achieved with a linear range of 1 × 10 2 to 1 × 10 6 cfu/mL. The recoveries of S. typhimurium spiked in pure milk samples were 92.48–94.05%.
Schematic diagram of the proposed colorimetric assay for S. typhimurium detection based on etching of bifunctional apt-Fe 3 O 4 @Ag NPs and inhibiting catalytic activity of urease by Ag + . A color change from yellow to pink can be observed and correlated to the concentration of S. typhimurium.
研究领域:
分析化学
·
微生物学
·
纳米技术
·
食品安全
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ANALYTICAL BIOCHEMISTRY
·
2016
·
IF 2.243
Jian-Dong Zhang,Hua-Lei Wu,Tong Meng,Chao-Feng Zhang,Xiao-Jun Fan,Hong-Hong Chang,Wen-Long Wei
Chiral vicinal amino alcohols are important chiral building blocks and intermediates in the pharmaceutical industry . The transaminase (TAm) catalyzed kinetic resolution of racemic amino alcohols provides a straightforward approach to access these important compounds. This study describes the development of a novel microtiter plate assay to screen vicinal amino alcohol-specific TAms using a tetrazolium red-based colorimetric assay to monitor the rate of α-hydroxy ketone formation at 510 nm. This approach is the first to determine the Michaelis-Menten parameters for a recombinant TAm (PpbauA) from Pseudomonas putida NBRC14164. The corresponding V max and K M values for both enantiomers of 2-amino-1-propanol and 2-amino-1-butanol were obtained, and the calculated kinetic E-factors of PpbauA toward 2-amino-1-propanol and 2-amino-1-butanol are 3 (S) and 6 (R), respectively. The method is sensitive and exhibits low level background coloration. Moreover, this method can be used to detect transaminase activity and enantioselectivity toward amino alcohols in a high-throughput format. Additionally, this simple method is compatible with the most widely used (R)- and (S)-selective transaminases and may be a broadly applicable tool for screening transaminases from a transaminase mutant library.
研究领域:
生物化学
·
药物化学
·
酶学
✓ 已验证
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）