What volume of solvent should I add to my ReadyCal standard (WAT058930 or WAT058931)? - WKB94857

ENVIRONMENT

• ReadyCal standards
• Standards preparation

ANSWER

For WAT058930, there is 4 mg of standard in each vial, except for the highest MW standards (highest in green and red capped vials, usually >1M Da), of which there is 2 mg. The customer is free to toggle the final concentration in each vial to what they think will work best with their system, column, and method. Waters basically recommends targeting 0.5 mg/mL for the highest MW standard and 1 mg/mL for everything else. Add 4 mL to all the vials and it will work out this way.

 The 2-mL kit (WAT058931) is just half of everything said above.

ADDITIONAL INFORMATION

Adding 4 mL to WAT058930 and 2 mL to WAT058931 is your best bet (which would probably work for >80% of customers). But Waters has not written this in the care and use manual because there’s no reason you can’t add 2 mL to the 4 mL vial to get higher concentration and perhaps reduce the injection volume (if you so choose) – it depends on each customer’s method.