Detection method for calcium ions in seawater

A detection method and technology for calcium ions, which are used in measuring devices, material analysis by electromagnetic means, instruments, etc., to reduce workload, improve sensitivity, and reduce experimental errors.

Active Publication Date: 2018-05-11
YANTAI INST OF COASTAL ZONE RES CHINESE ACAD OF SCI
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  • Abstract
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  • Application Information

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Problems solved by technology

However, this method is based on the traditional Nernst response in the detection process, that is, when the calcium ion activity changes by an order of magnitude, the potential change value of the calcium ion selective electrode is about 30mV, while the actual calcium ion activity change in seawater is very small, so the sensitivity needs to be further improved

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  • Detection method for calcium ions in seawater
  • Detection method for calcium ions in seawater
  • Detection method for calcium ions in seawater

Examples

Experimental program
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Embodiment 1

[0027] Such as figure 1 The detection device shown: the ion-selective electrode 1, the reference electrode 6 and the auxiliary electrode 5 are respectively drawn by wires to the electrochemical workstation, and the electrochemical workstation is connected to the computer; the ion-selective electrode is composed of a polymer sensitive membrane, an inner filling liquid and an internal reference Composition of electrodes.

[0028] (1) Preparation of calcium ion selective electrode sensitive membrane: weigh 76mg polyvinyl chloride, 152mg o-nitrophenyloctyl ether, 25.6mg inert lipophilic salt tetrakis(dodecyl)-tetrakis(4-chlorophenyl) Ammonium borate (ETH 500) and 2.7 mg of N,N-dicyclohexyl-N′,N′-dioctadecyl-3-oxaglutaramide (calcium ionophore ETH 5234) were dissolved in 3.5 mL of tetrahydrofuran, After stirring evenly, fix it in a glass ring with an inner diameter of 3.6 cm on a glass plate. After the tetrahydrofuran volatilizes, use a puncher to cut a transparent film with a di...

Embodiment 2

[0034] Such as figure 2 The detection device shown: the ion-selective electrode 1, the reference electrode 6 and the auxiliary electrode 5 are respectively drawn by wires to the electrochemical workstation, and the electrochemical workstation is connected to the computer; the ion-selective electrode is composed of a polymer sensitive membrane, an inner filling liquid and an internal reference Composition of electrodes.

[0035] (1) Preparation of solid-state calcium ion selective electrode: Weigh 76mg polyvinyl chloride, 152mg o-nitrophenyloctyl ether, 25.6mg inert lipophilic salt tetrakis(dodecyl)-tetrakis(4-chlorophenyl)boronic acid Dissolve ammonium (ETH500) and 2.7mg N,N-dicyclohexyl-N′,N′-dioctadecyl-3-oxaglutaramide (calcium ionophore ETH 5234) in 3.5mL tetrahydrofuran, stir well A polymer-sensitive film was obtained. Pipette 10 microliters of poly(3,4-ethylenedioxythiophene)-polystyrenesulfonic acid dropwise onto the glassy carbon electrode, let it dry at room temper...

Embodiment 3

[0040] (1) The same as the sensitive film in Example 1.

[0041] (2) The ion-selective electrode (1), the reference electrode (6), and the auxiliary electrode (5) are respectively connected to the electrochemical workstation as a detection device through wires (see figure 1 ) into the 10.0mM KCl solution, first measure the open circuit potential under the condition of zero current, and confirm that it is the baseline potential of the working electrode ( image 3 A); then according to the designed detection program, apply a cathode constant current of 4s 5 microamperes ( image 3 B), so that the ions to be measured in the solution are efficiently gathered on the polymer sensitive membrane of the working electrode, and finally the open circuit potential is applied for 120s according to the detection program design to make the working electrode spontaneously return to the initial baseline potential ( image 3 C); The potential change signal obtained when a constant current is ap...

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Abstract

The invention relates to calcium ion detection, in particular to a detection method for calcium ions in seawater. A polymer film calcium ion selective electrode is adopted as the working electrode, athree-electrode system is employed, and pulse constant current is applied for quantitative detection of calcium ions in seawater. The time and magnitude of applied cathode pulse current are optimized,the electrode presents super-Nernst response in the 10<-3>-10<-2>M Ca<2+> activity range (calcium activity in seawater), and the response slope is 104mV / dec. Compared with the traditional potential analysis method, the detection method can effectively improve the detection sensitivity of the electrode to calcium ion detection. The electrode has good selectivity on high content Na<+>, Mg<2+> and K<+> in seawater, and has good repeatability and stability. When the electrode is applied to practical seawater calcium ion concentration detection, the detection result coincides with the real calciumion concentration of seawater.

Description

technical field [0001] The invention relates to the detection of calcium ions, in particular to a method for detecting calcium ions in seawater. Background technique [0002] Calcium ion is a constant element in seawater, which is closely related to the marine biosphere and carbonate system. The growth process of organisms such as corals and shellfish in seawater cannot do without calcium ions. The precipitation and dissolution of calcium carbonate related to the concentration of calcium ions directly affects the pH value, total alkalinity, total carbon dioxide and partial pressure of carbon dioxide of seawater, which in turn is related to ocean acidification and global warming. Seawater is a complex system, in which the content of sodium ions, potassium ions, and magnesium ions, which have the same stability characteristics as calcium ions, is very high. In order to detect calcium ions in seawater with high selectivity and sensitivity, it is necessary to effectively avoid ...

Claims

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Application Information

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IPC IPC(8): G01N27/416
CPCG01N27/4161
Inventor 秦伟刘淑文丁家旺
Owner YANTAI INST OF COASTAL ZONE RES CHINESE ACAD OF SCI
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