Hach-Lange DR 3800 User Manual - Manual (Page 141)

141
Pour-Thru Cell
for proper flushing of any previous solution from the cell - so
methods that utilize a 10 mL sample volume cannot be used
directly. Tripling the sample and reagent volumes on these methods
(or use of 25 mL reagents and sample volumes) will provide
enough liquid to use the cell - however, an additional modification is
needed. Since the Pour-Thru Cell has a slightly shorter 1-inch
pathlength than the square cells for which most methods are
calibrated, it is necessary to multiply the results by a pathlength
factor of 0.95 or to perform a standard adjustment (
section 5.4.6 on
page 46 ) on any method that utilizes 1-inch square cells. Always
confirm results with a standard solution, to make sure modifications
have been performed correctly.
The methods listed in Table 18 require extra rinsing or purging of
the Pour-Thru Cell with deionized or distilled water between
samples.
The Pour-Thru Cell can also be used for the Nessler Method for
Ammonia and TKN if cleaned properly. Clean the cell by pouring a
few sodium thiosulfate pentahydrate crystals into the cell. Rinse out
the crystals with deionized water.
The methods listed in Table 19 cannot be used with the Pour-Thru
Cell due to problems caused by the chemistry or other
complications. Use the sample cell specified in the procedure for
these methods.
A.4 Pour-Thru Cell Maintenance
Note: Do not use solvents (e.g. alcohols or acetone) to clean the Pour-Thru
Cell. Use of aceton may damage the cell.
A dilute acid solution can be used
for cleaning. Rinse thoroughly with deionized water.
Check the cell occasionally for an accumulation of film on the cell
walls. If the walls appear dirty or hazy, or if bubbles form in the cell,
pour 50 mL of a detergent solution into the cell. Let it soak for
several minutes. Rinse thoroughly with deionized water. Use a soft
cloth to clean the sample cell walls. Paper towels and other paper
products may scratch the plastic and should not be used.
Table 18 Methods that require additional purging
Aluminum, Aluminon Chlorine Dioxide, LR Cobalt, PAN
Copper, Porphyrin Hardness, Calmagite Manganese, LR, PAN
Nickel, PAN Nitrate, MR Nitrate, HR
Table 19 Methods that cannot be used with the Pour-Thru Cell
Aluminum ECR Arsenic Barium Boron, Carmine
Cyanuric Acid Fluoride Formaldehyde Lead, LeadTrak
Mercury Nickel, Heptoxime Nitrite, HR PCB
Phenols Potassium Selenium Silver
Suspended Solids Sulfate TPH Volatile Acids
Zinc Surfactants, Anionic (Detergents)