Ready Cap® with Xtalscint®

Ready Cap is a small container coated on the bottom with Xtalscint solid scintillator. Simply pipette up to 200 µL of your single-labeled sample onto the Xtalscint layer, dry, and count.

Ready Cap is recommended for liquid samples containing non-volatile radioactivity that are:

• 200 µL or less.
• Not strongly colored. Red, yellow, green, and brown colors absorb the light emitted from Ready Cap.
• In low molarity buffers or organic solvents. Less than 1M is recommended; gradient samples of sucrose, or CsCl, non-volatile solvents, e.g., glycerol, are not recommended.
   

Ready Cap Applications
Ready Cap has been used in a wide variety of applications, including:

• Whole Cell and Membrane Receptor Assays (for counting reference (dose) standards)
• Transport Studies
• Enzyme Assays
• Radioimmunoassays
• Thymidine Incorporation
• Tumor Response Assays
• Counting of Alpha Emitters with Low Background
• Cytotoxicity Assays
• Counting Whole Blood without Bleaching

How to use Ready Cap

1. Add Sample
   Pipette up to 200 µL of aqueous or non-aqueous solution containing non-volatile radioactivity.
2. Dry
   The sample should be evaporated to dryness using one of the following methods. This is especially important for weak beta emitters such as Tritium. For more energetic isotopes (e.g., ³²P), drying may not be necessary to obtain acceptable results.
   1. Xtalscint Dryer from Beckman Coulter Uses heated forced air and dries 50 Ready Caps simultaneously in a numbered tray. Drying time is 45 minutes ore less, depending on the solvent.
   2. SpeedVac Rotor from Beckman Coulter For investigators with Savant SpeedVac centrifuges. The capacity is 50 Ready Caps and the drying time is similar to the Xtalscint Dryer.
   3. Heat Lamp
   4. Forced Air Convection Oven (60°C)
   5. Air Dry (overnight)
3. Count
   Place Ready Caps in standard 20 mL glass or plastic counting vials. The Ready Caps are easy to remove and the vials may be reused without fear of contamination. Plastic mini-vials may also be used but cannot reused as Ready Caps fit too snugly for easy removal. Since there is no cocktail, no vial caps are needed. If counting in an LS 6000 Series Scintillation Counter, use the Xtalscint CPM/DPM option, if installed. If not installed or when using other counters, use a wide open window and turn off the External Standard Quench Monitor.

Counting Efficiency
The following results were obtained with dry Ready Caps:

Ready Cap® with Xtalscint®