Instruction Manual MA-3000+RD-5+SC-5
NIC-TD-0000015-05
23
3.2. Preparation of a standard solution
Since the concentration of a mercury standard solution largely changes after being
prepared, measures should be taken such as making the solution acidic when diluting
it. Our company has obtained good results by adding L-cysteine when diluting it.
When the solution ages or is left in a warm place for a long time its stability decreases,
thus it must be stored in a cool dark place. Quality control measures such as writing
the date of preparation on the label should also be routinely taken.
(How to prepare)
(1) 0.001% L-cysteine solution (for dilution)
Weigh 10 mg of L-cysteine (not cystine), put it into a 1000mL flask, and add water.
Add 2mL of super high-grade concentrated nitric acid to this and let it
dissolve/uniformalize so that the total amount is 1000mL. Store in a cool dark
place.
(2) Standard mercury solution
To prepare a 10ppm standard solution, batch off 1mL of mercury standard solution
for atomic absorption (1000ppm) and dilute it with 0.001% L-cysteine solution so
that the amount is 100mL. Prepare standard solutions with the required
concentration by diluting in the same way. However, any mercury within the
reagent or distilled water must be taken into consideration when preparing
extremely low concentration solutions below ppb order.
*
When preparing low concentration solutions (below ppb order) for drawing
calibration curves, the concentration of the solution when measuring can be
maintained by adding 0.001% L-cysteine in an amount corresponding to 0.4% of
the total amount and then adding distilled water when diluting.
Summary of Contents for MA-3000 RD-5+SC-5
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