6.3-12
Section 6
ApplicAtions
Pinnacle Operators Manual
Pickering Laboratories Inc.
Upon completion of the analysis, follow the shutdown procedure described in Section 4. Store the carbamate
column in 100% Methanol
Note: The automatic valves prevent reagents from back-flowing onto the column. The inert gas should be left on
to preserve the OPA reagent.
Precautions for Carbamate Analysis
Always wear gloves during the preparation of the reagents. The OPA and Thiofluor™ can cause skin irritation.
The OPA reagent is sensitive to air oxidation, degrades over time, and should be prepared fresh for optimum
sensitivity. OPA reagent maintains its activity for up to one week when pressurized with inert gas.
Thiofluor
™
is extremely hygroscopic. Always keep in a tightly closed container.
The preparation of the OPA Diluent by the user is not recommended because sodium borate (any grades)
contains excessive amounts of heavy metal contaminants and insoluble matter. These impurities will eventually
precipitate in the reactor and flowcell. The one year warranty does not cover damage caused by these
contaminants.
Use HPLC-grade methanol and water (Fisher Scientific, JT Baker, or Merck) for carbamate analysis to avoid
problems with baseline drift, spurious peaks, and noise.
Use bottled HPLC-grade water if possible (Fisher Scientific, JT Baker, or Merck), especially during the initial
system start-up. If water from a water purification system is used, ensure the system has an activated charcoal
unit to eliminate organics, and that the charcoal cartridge is placed after the ion-exchange cartridges. (Many
ion-exchange resins leach out OPA-positive contaminates that cause unacceptable fluorescence background.)
The water in the solvent reservoir should be changed every 3 to 4 days to prevent possible bacterial growth.
The test mixture for carbamate is for qualitative use only. It is not recommended for calibration purposes.
Filter all samples through a 0.45µm membrane filter. Some samples may require even more stringent filtration,
especially if colloids are present.
Aqueous samples must always be properly buffered. Consult EPA Methods 531.1 or 531.2 for details.
For carbamate analysis with methanolic samples, inject – 10µl. Large amount of organic solvents can cause
peak distortion.
For small aqueous sample volumes (< 150µl) either of the two Pickering columns can be used. For volumes
greater than 300µl, use only the 25cm column. A gradient delay time should be programmed into the analysis
(0% organic) to trap the sample onto the head of the column.
Avoid purging the system with 100% acetonitrile as precipitation of borate salt in the reactor might occur. Do
not exceed 70% acetonitrile if it will be used as the mobile phase.
Do not store the column in water.
Use the Pickering Laboratories carbamate analysis column, which is specifically designed and tested for the
separation of carbamates in the EPA Methods.
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