natrium-ionselectieve electrode.

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natrium-ionselectieve electrode.

heey,

mijn leraren hebben geen werkwijze voor de natrium-ionselectieve electrode.

ik zou graag willen weten of daar een voorschrift van is?

greatzzz

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Re: natrium-ionselectieve electrode.

Een werkwijze of voorschrift slaat meestal op een bepaling. Een bedieningsvoorschrift of gebruiksaanwijzing heeft betrekking op apparatuur. Aangezien een ion-selectieve electrode onder apparatuur valt, is mijn vraag: wat bedoel je precies? Hoe een ionselectieve electrode is opgebouwd, of hoe je een bepaling moet doen met een ionselectieve electrode? Indien je het laatste bedoelt, is het handig als je wat meer achtergrondinformatie neerzet (soort stof, titratievloeistof, enz).
I'm not suffering from insanity - I'm enjoying every minute of it!!

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Re: natrium-ionselectieve electrode.

Voor een bepaling met een natrium ion selectieve elektrode moet je even kijken op mijn homepage bij chemische experimenten. :lol:

homepage Ron

MvG Ron

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Re: natrium-ionselectieve electrode.

heb je hier iets aan:

Determination of sodium with the ion-selective electrode

Summary

The determination of sodium with the sodium ISE represents a selective, quick

and relatively exact method that will be described in this bulletin. Examples will be

used to demonstrate how determinations can be carried out with the 692 pH/Ion

Meter using either direct measurement or the standard addition technique. The sodium concentration of waste water, spinach and urine have been determined.

Application Bulletin No. 83/4 e

Determination of sodium with the ion-selective electrode Page 2

Reagents

• Na+ standard solution: 5.084 g NaCl puriss p.a. are dissolved in dist. water

and the solution is filled up to 1 L:

r(Na+) = 2000 mg/L

• ISA solution: c(Tris(hydroxymethyl)-aminomethane) = 1 mol/L; the

pH value of the solution is adjusted to 8 ... 10 by adding

HNO3.

For measurements <1 mg/L the ISA solution has to be

diluted 1 : 5.

Ratio ISA : sample solution = 1 : 1

• Conditioning solution: c(NaCl) = 0.1 mol/L

Handling of the electrode

To achieve optimal measurements, observe the following points:

• Before the first measurement, the electrode has to be shaken like a fever thermometer.

• When out of use, or before being used for the first time, the sodium-selective

electrode should be activated by immersing overnight in 0.1 mol/L NaCl.

• With the reference electrode, take care that the internal parts are thoroughly

wetted. If necessary, extract trapped air from the inside with a water jet pump

before using for the first time.

• After every measurement rinse the electrodes thoroughly with dist. water and

wipe off gently with a damp cloth.

• Potassium interferes with the determination of sodium if it is present in more

than 100 fold excess.

• As the sodium-selective electrode responds to H3O+ ions like a pH glass electrode at low pH values, measurements have to be carried out in the alkaline pH

range (pH = 8 ... 10).

• For interferences caused by other ions see the Instructions for use of the electrode.

General hints

• All solutions used have to be stored in plastic containers.

• Stir during additions (stirring parameter 692: «ON=> or «control=>). Check to

make sure that the stirrer is turned on and that a stirring rod is in the measuring

vessel. Additions without concurrent stirring lead to false results!

• Choice of procedure:

Standard addition is a quick and reliable method especially for undefined sample matrices. A direct measurement is indicated when many measurements of

similar solutions are to be carried in a defined and unproblematic sample matrix.

• The addition of ISA solution before the measurement keeps the ionic strength

constant.

5).

• Low sodium concentrations:

For concentrations <1 mg/L the standard solutions must have the same ionic

background as the sample solutions. The ISA solution has to be diluted 1 : 5.

The adjustment time becomes distinctly longer. The blank values of the chemicals are to be taken into account.

• All measurements should be performed at constant temperature (for example,

at 25 ºC).


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Re: natrium-ionselectieve electrode.

Ik heb de werkwijze ook nodig. Moest iemand deze hebben zou dit zeer handig zijn. 

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