- Technical Service
- How do I initially “charge” the AC Blocks™?
Answer: Place the AC Block™ into an empty CryoCooler™ or a Styrofoam container. Pour LN2 up to, but not past, the block’s aluminum grate and incubate for five minutes. Place one grinding ball into each vial, loosely cap, and load vials into the AC Block™. NOTE: Do not pour LN2, or allow LN2 to seep, into the vials, as pressure can build in the tubes causing them to crack or explode. Loosely capping the vials during incubation will mitigate pressurization. Once incubation is complete, the AC Block™ has been sufficiently charged and samples can be loaded into the vials.
- Can AC Blocks™ be charged by placing in a -80°C freezer?
Answer: No, AC Blocks™ have been designed to be fully charged in liquid nitrogen. Samples will not be sufficiently cool if AC Blocks™ are placed in a freezer.
- How do I replace the absorbent insert?
Answer: To replace the absorbent insert, push down on the aluminum grate and tilt the grate to the side until it is released. Remove the insert and replace with a Replacement Absorbent Inset. Place grate back onto the block by inserting on a slant until it is secured underneath the screws.
- How often should the absorbent inserts be replaced?
Answer: Replacement of inserts is highly dependent on use and care of the blocks. Remove grate and inspect quality of the insert. If there is significant wear, remove the insert and replace. Insert should be replaced immediately if hazardous chemicals have spilled on the AC Block™.
- Can I use other vials in the AC Blocks™?
Answer: Yes, AC Blocks™ can accommodate most standard 4 ml vials, although we recommend our 4 ml polycarbonate vials for their durability. Polyethylene, a common vial material, is more malleable that polycarbonate and can crack when used for cryogenic grinding.
- Why do I need to loosen the cap before placing vials into the AC Block™?
Answer: While LN2 levels should not exceed the aluminum grate of the AC Block™ (and, consequently, not approach the cap-line), LN2 vapors and any potential seepage will pressurize the vials. This can be moderated by loosely capping the vials and avoiding a tight seal during incubation. (Please note, caps should be tightened prior to running the block on a plate homogenizer).
- How do I load samples into the vials?
Answer: After vials have been placed in liquid nitrogen, vials should be removed using the appropriate safety precautions (e.g. using gloves and/or tongs, etc.) and following your institution’s recommended safety guidelines. Tilting each vial, roll the grinding ball into the cap and unscrew the cap. Using tweezers (or the equivalent), insert sample into the vial until it has reached the bottom. Transfer the grinding ball into the vial, placing it on top of the sample. Loosely screw on the cap, until ready for homogenization.
- How long should I allow LN2 to drain from the block?
Answer: Allow LN2 to drain from the AC Block™ until the flow of the liquid allows for easy transfer to the plate homogenizer. Generally, 15-20 seconds should be sufficient, but always follow your institution’s guidelines for the proper handling of LN2.
- Can I homogenize less than 12 vials in the AC Block™?
Answer: Yes. All 12 vials need not be loaded into the AC Block™ for homogenization. Vials should be evenly spaced in the center of the AC Block™ if less than 12 vials are used.
The AC Block™ Kit provides an effective, high throughput tool for cryogenic grinding of samples. The kit includes two AC Blocks™, which are aluminum cooling blocks with absorbent inserts. When charged with liquid nitrogen (“LN2”), the AC Blocks™ release vapor and actively cool samples during the homogenization process. The lightweight block design reduces stress on plate homogenizers normally experienced when using solid aluminum cryogenic blocks. Each block holds 12 x 4 ml polycarbonate vials (included), whose durability makes them best-suited for cryogenic grinding.
Each AC Block™ Kit includes:
Two AC Blocks™
Two Replacement Absorbent Inserts
48 x 4 ml Polycarbonate Vials
48 x 4 ml Polyethylene Lined Screw Caps
48 x 3/8” 440C Stainless Steel Grinding Balls.