MICROCHEMICAL JOURNAL
·
2024
·
IF 4.9
Xuefei Zhang,Fanfei Min,Lingyun Liu,Lujun Wang,Qi Liu
Ca 2+ is an important ion in industrial wastewater such as coal slurry water. The concentration of Ca 2+ directly affects the water quality of recycled water, the physicochemical properties of particle surfaces, and the effectiveness of coal beneficiation. However, the determination of Ca 2+ in coal slurry water is influenced by other coexisting metal ions (M: K + , Na + , Mg 2+ , and Al 3+ ) in the system. The complexation color development – visible spectrophotometry (CCDVS) has been proven to be a rapid and accurate way to determine Ca 2+ . This study investigates the impact and mechanism analysis of factors such as the concentrations of coexisting ions (K + : 0–15 mg/L, Na + : 0–2000 mg/L, Mg 2+ : 0–20 mg/L, Al 3+ : 0–0.05 mg/L) and valence states (monovalent, divalent, trivalent) on the accurate determination of Ca 2+ using the CCDVS method. All ions are interested in the indicator, with the light absorption intensity order of Al 3+ (Abs = −1.783) > Mg 2+ (Abs = −1.723) > Ca 2+ (Abs = −1.248) > K + (Abs = −0.268) > Na + (Abs = −0.075) under the same ions concentration (e.g. 16 mg/L). Interestingly, the absorbance of Ca–M mixed solutions shows different trends. For example, adding Na + decreases the absorbance value of Ca 2+ , with a decrease in Abs of 0.065 when the Na + concentration is 2000 mg/L. This indicates a competitive relationship between the complexation color development reaction of Ca and Na due to the same reaction mechanism. However, for Ca–Mg mixed solutions, when the Mg 2+ concentration increases to 15 mg/L, the increase in Abs is 0.078, attributed to the stronger absorption of Mg 2+ occupying the adsorption sites of Ca 2+ . On the contrary, at industrial concentrations, the influence of K + (0–20 mg/L) and Al 3+ (0–0.05 mg/L) on Ca 2+ detection can be ignored. Complementary characterization (XRD, XPS) and DFT theoretical calculations indicate that complexation color development reaction depends on the adsorption of metal ions on the sulfonic acid sites on the indicator. Other metal cations compete with Ca 2+ for the same adsorption sites, and the reactivity of metal ions with the indicator is as follows Al 3+ > Mg 2+ > Ca 2+ > K + > Na + . Therefore, this study provides technical and theoretical support for the development of highly selective Ca 2+ detection methods, aiding in the rational control of chemical agent dosages.
研究领域:
环境科学
·
分析化学
✓ 已验证
产品关联
DOI
高影响因子
SYNTHETIC METALS
·
2020
·
IF 3.286
Yiwen Huang,Weilin Zhou,Ye Wang,Yiming Zhang
Due to the weak coordination of alkaline−earth metal ions (such as Mg 2+ , Ca 2+ and Sr 2+ ), the design for corresponding fluorescent probes in vitro is much harder than those for heavy metal ions (such as Cu 2+ , Hg 2+ and Pb 2+ ). In this paper, the crown ether-like structure was introduced in graphene quantum dots (C-GQDs) via the hydrothermal treatment of alizarin . With the strong coordination of crown ether-like structure in C-GQDs’ lattice, C-GQDs show much lower detection limit to Ca 2+ (2 pM) than that of surface modified graphene quantum dots (100 pM). Moreover, the selectivity of C-GQDs can be controlled by the size modulation of crown ether-like structure. Precursors with different structures were carried out to modulate the size of crown ether-like structure in C-GQDs. The obtained C-GQDs show good selectivity for Mg 2+ , Sr 2+ , and Ba 2+ , respectively. Finally, we also show the successful detection of Ca 2+ in vitro based on C-GQDs.
研究领域:
材料科学
·
纳米技术
·
分析化学
✓ 已验证
DOI
高影响因子
MICROCHEMICAL JOURNAL
·
2025
·
IF 5.1
Dali Zhuo,Xiaoyu Dong,Linghuan Li,Ronghua Zeng,Chao Tan,Hong Luo,Zhirong Zou
Calcium ion (Ca 2+ ) is one of the important nutrients for humans, excessive and insufficient intake may both cause diseases, so that it is of great importance to analysis of Ca 2+ in our daily life. In this work, a portable gas pressure meter-based method was developed for the detection of Ca 2+ in water samples and calcium gluconate oral liquids. Ca 2+ in solution was extracted and precipitated by the addition of Na 2 C 2 O 4 , CaC 2 O 4 precipitate was formed and then filtered from the complicated matrix through a filter membrane. The filter membrane (containing CaC 2 O 4 precipitate) was then treated by H 2 SO 4 solution, CaC 2 O 4 precipitate was dissolved during this step and H 2 C 2 O 4 was formed. In a sealed bottle-in-bottle reaction device, H 2 C 2 O 4 reacted with acidic KMnO 4 solution to generate CO 2 gas, causing a significant gas pressure increase and it was readout by a hand-held pressure meter. A standard curve with linear range of 1–80 mmol L −1 and a limit of detection of 0.4 mmol L −1 were obtained. This system was subsequently applied to the detection of Ca 2+ in several water samples and oral liquids, recoveries of 92–110 % were obtained for their spiked samples. Only a few reaction bottles and a gas pressure meter were required in this system. It is a low-cost, sensitive, rapid and easy-used analytical method for on-site determination of Ca 2+ .
研究领域:
分析化学
·
营养学
·
环境监测
✓ 已验证
产品关联
DOI
高影响因子
Biosensors-Basel
·
2022
·Vol. 12
·期 5
·331
·
IF 5.743
Zhixue Yu,Hui Wang,Yiguang Zhao,Fan Zhang,Xiangfang Tang,Benhai Xiong
An electrochemical biosensor for detecting Ca2+concentration was proposed using glass carbon electrodes (GCEs) modified with nitrogen-doped graphene (NGR), gold nanoparticles (AuNPs) and DNAzyme. The resistance signal was amplified through two methods: electrochemical reduction of AuNPs on the NGR surface to increase the specific surface area of the electrode and strengthen the adsorption of DNAzyme; and increasement of the DNAzyme base sequence. The process of electrode modification was characterized by scanning electron microscopy, Raman spectroscopy, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). Experimental parameters’ influence, such as the deposition time of gold nanoparticles and the detection time, were assessed by electrochemical methods. The linear ranges of the electrochemical biosensor were in the range from 5 × 10−6to 5 × 10−5and 5 × 10−5to 4 × 10−4M, with a detection limit of 3.8 × 10−6M. The concentration of Ca2+in the serum of dairy cows was determined by the biosensor with satisfactory results, which could be potentially used to diagnose subclinical hypocalcemia.Keywords:electrochemical biosensor;nitrogen-doped graphene;gold nanoparticles;DNAzyme;dairy cow;hypocalcemia
研究领域:
生物化学
·
分析化学
·
兽医学
✓ 已验证
DOI
PubMed
高影响因子
SENSORS
·
2022
·Vol. 23
·期 1
·353
·
IF 3.847
Rong Zhang,Tiantian Hao,Shihui Hu,Kaiyang Wang,Shuhui Ren,Ziwei Tian,Yunfang Jia
Flexible electrolyte-gated graphene field effect transistors (Eg-GFETs) are widely developed as sensors because of fast response, versatility and low-cost. However, their sensitivities and responding ranges are often altered by different gate voltages. These bias-voltage-induced uncertainties are an obstacle in the development of Eg-GFETs. To shield from this risk, a machine-learning-algorithm-based LgGFETs’ data analyzing method is studied in this work by using Ca2+detection as a proof-of-concept. For the as-prepared Eg-GFET-Ca2+sensors, their transfer and output features are first measured. Then, eight regression models are trained with the use of different machine learning algorithms, including linear regression, support vector machine, decision tree and random forest, etc. Then, the optimized model is obtained with the random-forest-method-treated transfer curves. Finally, the proposed method is applied to determine Ca2+concentration in a calibration-free way, and it is found that the relation between the estimated and real Ca2+concentrations is close-to y = x. Accordingly, we think the proposed method may not only provide an accurate result but also simplify the traditional calibration step in using Eg-GFET sensors.Keywords:electrolyte-gated graphene field effect transistor;Ca2+detection;machine learning;regression model;calibration-free;flexible
研究领域:
材料科学
·
纳米技术
·
生物传感器
·
机器学习
✓ 已验证
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）