LaMotte SMART Spectro Spectrophotometer - Manual (Page 186)

MOLYBDENUM
THIOGLYCOLATE METHOD • CODE 3699-02-SC
QUANTITY CONTENTS CODE
2 x 30 mL * Mo Buffer *3997-G
2 x 30 mL * Molybdenum Oxidizing Reagent *6485-G
2.5g * Molybdenum Indicator Powder *6486-S
1 Spoon, 0.05g, plastic 0696
2 Pipets, 1.0 mL, plastic w/cap 0372
*WARNING: Reagents marked with an * are considered to be potential health
hazards. To view or print a Material Safety Data Sheet (MSDS) for these reagents
go to www.lamotte.com. To obtain a printed copy, contact LaMotte by e-mail,
phone or fax.
Molybdenum occurs naturally in the earth’s crust as molybdenite and wolfenite,
and is an important element in many biochemical reactions, including nitrogen
fi xation. In industrial processes, such as the operation of boilers and cooling
towers, molybdenum, in the form of sodium molybdate, is used as a corrosion
inhibitor.
APPLICATION: Boiler and cooling waters.
RANGE: 0.0–15.0 ppm Molybdenum
MDL: 0.2 ppm
METHOD: Calcium thioglycolate reacts with molybdenum to give a
yellow color with an intensity proportional to the amount
of molybdenum present.
SAMPLE HANDLING
& PRESERVATION:
Molybdenum samples may be stored in either plastic or
glass containers.
INTERFERENCES: Nickel levels less than 50 ppm do not interfere;
aluminum levels less than 10 ppm do not interfere;
chromate at higher concentrations interferes due to
the intense yellow color. Ferrous iron levels below 50
ppm do not interfere, but low levels of ferric iron will
cause a large blank. Highly buffered samples may
exceed the capacity of the system possibly producing
inaccurate results. Samples with high levels of nitrite will
eventually develop a pale orange color. Scan the sample
immediately to avoid this interference.
SMART Spectro Test Procedures 2.11 MOLYBDENUM
Test P
rocedures