Chemistry Reference
In-Depth Information
Apparatus
Dionex 2010i ion chromatograph, Dionex electrochemical detector, Houston Instrument
Omniscribe chart recorder.
Conditions
Electrochemical applied
potential
0.4V
0.25cm min
−1
Chart recorder speed
1.5ml min
−1
Flow rate
Dionex 4M S
1
membrane suppressor
Suppressor column
Injection volume
0.1mL
Reagents
For monovalent ions:
Eluant
0.0016mol L
−1
Li
2
CO
3
+0.0024mol L
-1
LiCOOH,
H
2
0 pH=10.4 monovalent cations and anions
Separator columns
Anion separator
150×4mm id Dionex HPLC-A 53 anion
Cation separator
200×4mm id Dionex HPLC-CS 2 cation
0.0033mol L
−1
copper phthalate divalent cations and anions
For divalent ions:
Eluant
Separator columns
Anion separator
250×4.6mm id Vydac 3021 C 4.6 anion
Cation separator
200×4mm id Dionex HPLC-CS 1 cation
All standard anion and cation solutions were prepared by the appropriate dilution of
standard stock solutions using distilled deionised water. The salts used to prepare these
solutions were ACS Certified quality.
Two different eluants were used, lithium carbonate-lithium acetate dihydrate, and
copper phthalate. A stock solution of the lithium carbonate lithium acetate dihydrate
eluant was prepared from ACS Certified salts using distilled deionised water with the
appropriate dilution to obtain the working eluant.
The copper phthalate eluant was prepared by mixing a solution of cupric acetate with
an excess of potassium hydroxide and filtering the resulting cupric hydroxide precipitate.
The cupric hydroxide precipitate was then mixed with an equimolar amount of phthalic
acid and heated gently overnight to produce copper phthalate.
Procedure
All water samples were injected and analysed as received without prior preparative steps.
If dirty samples had been analysed filtering is necessary to remove the solid particles
prior to injection on the ion chromatograph.
The normal procedure for the use of the ion chromatograph was followed, with the
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