ORBECO SP600, Instruction Manual, Page: 34 / 334

32 SP600 Spectrophotometer 01/2008
4
3
2
1
1.1 Methods
Arsenic
0.02 – 0.6 mg/l As
Reagents (note 2):
• 40 % Sulfuric Acid (H
2
SO
4
) p.a.
• Dissolve 8.33 g Potassium Iodide (KI) p.a. in 50 ml of
deionized water
Note: stored in a dark bottle it can be used for 1 week
• Dissolve 4.0 g Tin(II)-chloride-Dihydrate (SnCl
2
• 2H
2
O)
p.a. in 10 ml Hydrochloric Acid (HCl) 25 % p.a.
• 2.0 g Zinc coarse powder
(Zn; particle size about 0.3-1.5 mm) p.a.
• Absorption solution:
Dissolve 0.25 g Silver diethyldithiocarbamate
(C
5
H
10
AgNS
2
) p.a.
and
0.02 g Brucine (C
23
H
26
N
2
O
4
) p.a. in
100 ml 1-Methyl-2-pyrrolidone extra pure (C
5
H
9
NO)
and store in a dark bottle.
If it is not possible to dissolve completely, stir for min.
1 hour and filtrate to get a clear solution.
Notes:
• use only dry glass vessels
• stored in a dark glass bottle at max. 20°C the absorp
-
tion solution can be used for about 1 week
• store Silver diethyldithiocarbamate at 4°C.
Part list for glass apparatus:
• 100 ml Erlenmeyer flask (NS29/32) Order code: 37 05 01
• glass stopper (NS29/32) Order code: 37 05 02
• absorption tube (NS29,2/32) Order code: 37 05 03
Assembling of apparatus:
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