INSTRUCTION MANUAL
CODE 80187
REV D
01/2021
Page: 36
J
.P. SELECTA s.a.u.
Autovía A-2 Km 585.1 Abrera 08630 (Barcelona) España
Tel 34 937 700 877 Fax 34 937 702 362
e-mail: selecta@jpselecta.es - website: http://www.grupo-selecta.com
7 Reagents
The reagents to be used must be free of ammonia.
7.1 Prepared reagents
The best thing is to use reagents factory prepared, mainly the HCl for titration. Any
error on its preparation have a direct influence on the result.
As an example the following reagents could be used, or the equivalent one in other
brands:
Boric acid 4%
RV
PANREAC 282222
(For ammonia titration)
Mixed indicator 5 RV
PANREAC 283303
(Red of Green Bromocresol)
Mixed indicator 4.4 RV
PANREAC 282430
(Red of Blue of metilene)
HCl 0.1N SV
PANREAC 171023
HCl 0.25N
SV
PANREAC 182318
H
2
SO
4
0.1N
SV
PANREAC 181061
H
2
SO
4
0.2N
SV
PANREAC 182011
Acetanilide 99% (Validation standard)
PANREAC 151005
Ammonia sulphate (Validation standard)
PANREAC 131140
Kjeldahl Catalyst 6.25% Cu tabl. 8g
PANREAC 174428
7.2 Proper reagents set up
As it is usual on most laboratories, the reagents to work with PRO-NITRO «M»
could be prepared starting from concentrated ones.
The NaOH 40%, acid Boric 4% are not critical on the concentration and it is not
necessary to work with precision.
Reagents for titration (HCl or H
2
SO
4
) must be high precision and calculation must
be accurate. Any error on its preparation has a direct influence on the result.
