Hach Micro Dist User Manual

43
Section 11 Cyanide–5
11.1 Micro Dist™ Method
DANGER
Chemical inhalation hazard. To avoid potential exposure to
cyanide gas (HCN), the manufacturer recommends operating
the Micro Dist under a fume hood.
DANGER
Risque d'inhalation de produit chimique. Pour éviter le contact
potentiel avec du gaz de Cyanure d'hydrogène (HCN), le
fabricant recommande d'utiliser le Micro Dist sous une hotte
aspirante.
CAUTION
Chemical hazard. Always follow appropriate laboratory safety
procedures when handling chemicals. Always wear personal
protective equipment appropriate for the chemicals you are
handling.
ATTENTION
Danger chimique. Suivez toujours les procédures de
laboratoire de sécurité lors de l'utilisation de produits
chimiques. Veuillez toujours porter l'équipement de protection
personnel approprié pour les produits chimiques que vous
manipulez.
This is a method for preparing and distilling samples containing
0.05 to 50 mg Free and Combined Cyanide/L in the presence of
sulfide with the Micro Dist distillation apparatus.
In the following procedure,
D and M refer to the marks on the ends
of the collector tube.
D means 'distillation' or 'discarded' end and M
means 'measuring' end. See Figure 2 on page 13.
1. Set the controller to 120
°C. Allow the heater block to warm up.
This will take about 40 minutes.
2. With the
M end up, put the required number of collector tubes
into the collector tube rack. When using the Pre-filled collector
tubes, re-seal the foil pack after removing the tubes if there are
any left. When using the User-Fill collector tubes, fill and cap
the tubes before using.
3. Put the required number of collector tubes into the sample tube
rack; up to 21 for one block. Place 6.0 mL of sample (or
standard) into each sample tube with an automatic pipet.
4. Add between 0.5 to 1.0 g of soil or sludge to 5 mL of DI water. If
the sample is high in organics, a smaller sample size or less DI
water may be required. Foaming or caking of the membrane is
often eliminated by the above measures. If not, see Running
Solid Samples with Micro Dist on page 70.
5. In this method, it is imperative that the standards be distilled
with the samples.
6. In order to both release the free cyanide as HCN and to digest
complexed cyanides during the digestion/distillation, first prime
the re-pipettor several times into a waste container. Add 0.75
mL of 7.11 M sulfuric acid / 0.79 M magnesium chloride solution

Hach Micro Dist Specifications

General

Brand	Hach
Model	Micro Dist
Category	Measuring Instruments
Language	English