LaMotte SMART Spectro Spectrophotometer - Manual (Page 130)

CYANIDE
PYRIDINE-BARBITURIC ACID METHOD • CODE 3660-SC
QUANTITY CONTENTS CODE
60 mL Cyanide Buffer 2850PS-H
5 g * Cyanide Cl Reagent *2794DS-C
5 g * Cyanide Indicator Reagent *2793DS-C
15 mL * Hydrochloric Acid 1N *6130-E
15 mL * Sodium Hydroxide 1N *4004-E
2 Spoons, 0.1 g, plastic 0699
1 Pipet, plastic, 1.0 mL 0354
1 pH Short Range Test Paper,
pH 9–14 2955
1 Stirring Rod, Plastic 0519
*WARNING: Reagents marked with a * are considered to be potential health hazards. To view
or print a Material Safety Data Sheet (MSDS) for these reagents see MSDS CD or
www.lamotte.com. To obtain a printed copy, contact LaMotte by e-mail, phone or fax.
The presence of cyanide in water has a significant effect on the biological
activity of the system. Cyanides may exist in water in a variety of forms which
vary in toxicity. Cyanide is a by-product of industrial waste from petroleum
refining and plating.
APPLICATION: Low level concentrations in drinking and surface waters;
domestic and industrial waters. This method determines only
those cyanides amenable to chlorination.
RANGE: 0.00–0.500 ppm Cyanide
METHOD: Cyanides react with a chlorine donor to form cyanogen
chloride, which subsequently reacts with Pyridine and
Barbituric Acid to form a red-blue compound in proportion
to the amount of cyanide originally present. The
concentration of the red-blue compound is determined
spectrophotometrically.
SAMPLE
HANDLING &
PRESERVATION: Cyanide solutions tend to be unstable and should be
analyzed as soon as possible. Samples can be stabilized by
adjusting the pH to greater than 12 with NaOH. However,
the pH will have to be readjusted to pH 10.5 before
performing the test.
INTERFERENCES: Oxidizing agents and aldehydes can react with cyanide, while
reducing agents, such as sulfite, react with the chlorine
donor; both can cause negative interferences. Thiocyanate
and cyanogen chloride both react as cyanide in this test and
will give a positive interference. Color and turbidity can also
interfere.
SMART SPECTRO TEST PROCEDURES 05.04 Cyanide 1/2