Hach DR/700 Procedures Manual page 405

(0 to 140 µg/L)
LEAD
For water and wastewater
Dithizone Method†*; USEPA accepted for reporting
Digestion is required (see Section 1)**
1.
Fill a 250-mL
graduated cylinder to
the 250-mL mark with
sample.
Note: If samples cannot
be analyzed immediately,
see Sampling and
Storage following these
steps. Adjust the pH of
the stored samples before
analysis.
Note: The DR/700 must
be calibrated before
sample measurement.
See Calibration
following these steps.
Note: Clean all
glassware with a Nitric
Acid Solution, 1:1. Rinse
with demineralized
water.
Note: Cloudy or turbid
samples may require
filtering before testing.
Report results as µg/L
soluble lead. Use a glass
membrane filter to avoid
lead adsorption on filter
paper.
†User calibration is required; range is approximate.
*Adapted from Snyder, L.J. Analytical Chemistry, 1947, 19, 684
**Procedure is equivalent to Standard Method 3500-Pb D for wastewater.
2.
Transfer the
sample into a 500-mL
separatory funnel.
52-79
Method 8033
3.
Add the contents
of one Buffer Powder
Pillow, citrate type
for heavy metals.
Stopper and shake to
dissolve.
Note: Spilled reagent
will affect test accuracy
and is hazardous to skin
and other materials.