YSI 9300 Photometer - Manual (Page 134)

Reagents and Equipment
For Hexavalent Chromium :-
YSI Chromicol No 1 Tablets
YSI Chromicol No 2 Tablets
YSI 9300 or 9500 Photometer
YSI Test Tubes, 10 ml glass (PT 595)
For Trivalent and Total Chromium :-
YSI Chromicol CR Reagent (Spoon Pack)
YSI Pretreatment Tube, 20 ml plastic (PT 526)
Filtration Kit, 0.45µm (PT 601)
Chromicol CR Reagent and the Pretreatment Tube are additional items required
in the tests for total and trivalent chromium. These items are available as a
supplementary pack (AT 283) for use in conjunction with standard Chromicol
reagent packs (PM 281 and AP 281).
A filtration is required during the course of the procedure for total and trivalent
chromium. The use of YSI Filtration Kit (PT 601) is recommended for this
purpose. Alternatively, standard laboratory equipment with Whatman 0.45µm or
equivalent membrane filters may be used.
Test Procedure - Hexavalent Chromium
1 Fill round test tube to the 10 ml mark.
2 Add one Chromicol No 1 tablet, crush and mix to dissolve.
3 Add one Chromicol No 2 tablet, crush and mix to dissolve.
4 Stand for 10 minutes without disturbing the solution to allow full color
development and to enable any undissolved particles to settle.
5 Select Phot 55 on the photometer.
6 Take photometer reading in the usual manner (see photometer instructions).
(Result A).
7 The result represents the hexavalent chromium concentration (chromates and
dichromates) as mg/l Cr. Stop the test at this stage if only hexavalent
chromium determination is required.