LaMotte SMART 2 - Manual (Page 175)

LEAD
PAR METHOD
· CODE 4031
QUANTITY CONTENTS CODE
250 mL *Ammonium Chloride Buffer *4032-K
15 mL *Sodium Cyanide, 10% *6565-E
30 mL *PAR Indicator *4033-G
30 mL Stabilizing Reagent 4022-G
15 mL *DDC Reagent *4034-E
1 Syringe, 5 mL, plastic 0807
2 Pipet, 0.5 mL, plastic 0353
*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.
The average concentration of lead is 0.003 ppm in streams and less than 0.1
ppm in groundwater. Lead in a water supply may come from mine and smelter
discharges or from industrial waste. Lead is used in the production of batteries,
solder, pigments, insecticides, ammunition and alloys. Tetraethyl Lead has been
used for years as an anti-knock reagent in gasoline. Lead may also enter water
supplies when corrosive water dissolves pipes, plumbing fixtures and materials
containing lead. Lead accumulates in the body and is toxic by ingestion.
APPLICATION: Drinking and surface waters; domestic and industrial
wastewater.
RANGE: 0.00–5.00 Lead
METHOD: Lead and calcium ions form a red complex with PAR
(4-
[2’-pyridylazo] resorcinol), at a pH of about 10. When
sodium diethyldithiocarbamate is added, the lead/PAR
complex is destroyed leaving the calcium/PAR complex. The
difference between the two measurements is due to the lead
concentration.
SAMPLE
HANDLING &
PRESERVATION: Analyze sample as soon as possible. If sample must be stored,
acidify with nitric acid to a pH of below 2.
INTERFERENCES: Calcium greater than 100 ppm (250 ppm CaCO
3
) will
interfere. Low concentrations of cerium, iron, manganese,
magnesium, sulfur, tin, and EDTA will also interfere.
MDL: 0.1 ppm
Smart2 TEST PROCEDURES 9.10 Lead 1/2