The Determination of the Metastable Zone Width - Case Study Lysozyme
When looking to purchase sample prep equipment, there are four questions to keep in mind. These are:
- What type of sample is being prepared?
- What is the application?
- What is the sample size?
- What is the throughput? (How many samples are being analyzed per day or on a single instrument?)
Sample prep crushing and grinding
These instruments use impact, attrition, shearing, compression, or a combination of these forces to crush or grind samples. Impact force works by collision.
Impact force – an object is repeatedly slammed into the sample delivering a shock that pulverizes the sample through repetitive impacts.
Attrition force – causes smaller particles to break off larger particles by rubbing against the surface of the mill or each other.
Shearing force – essentially shears, or cuts, portions of the sample off the larger sample. One surface is pushed in one direction against the sample while another surface is pushed in the opposite direction.
Compression force – exerts physical inward pressure causing brittle samples to compress and, as a result, break.
Crushing and grinding products
Ball mills
Ball mills like the planetary ball mill and Mixer/Mill® use impact force and attrition force. Grinding balls and the sample are added to a vial or jar where they are rotated or shaken rapidly. The balls slam against the sample and particles also rub against the surface of the mill and each other. Ball mills are ideal for inorganic samples like rocks, minerals, cement, ceramic, glass, and pharmaceutical tablets.
Bead beaters
Bead beaters, also known as homogenizers, like the Geno/Grinder®, MiniG®, and GenoLyte® also use both impact and attrition forces. Small grinding balls, or beads, are added to a vial together with the sample and rapidly agitated which breaks down cell membranes, a process called cell lysis. Bead beaters are used primarily for organic samples because their main purpose is breaking open cell membranes and only living things like plants, animals, fungi, and bacteria have cells. They can, however, be used to create fine powders out of inorganic samples like pharmaceutical tablets.
Ring and puck mills
Ring and puck mills like the ShatterBox® use attrition force. A grinding container with a puck swings in a tight high-speed circle grinding the sample in the rings. Ring and puck mills are ideal for inorganic samples like rocks, minerals, cement, ceramic, glass, and pharmaceutical tablets.
Cryogenic mills
Cryogenic mills like the Freezer/Mill® and the Cryo-Blade™ use a combination of embrittlement (making the sample brittle through freezing), impact, and shearing forces. It is important to note that the Freezer/Mill would not work without a cryogen. A cryogen is a substance like liquid nitrogen that is used to produce very low temperatures.
The Freezer/Mill is used for organic samples and hard inorganic samples like electronic components. Our Cryo-Blade, on the other hand, has only been tested on plant tissue and soft animal tissue at this time.
Sample Prep Equipment Selection Guide
| Equipment Type | Sample type | Sample size* | Throughput | Output |
| Organic samples | Inorganic samples | Small | Medium | Large | Extra-large | High | Low | Fine powder | Ultra-fine powder | Lysates |
| Plant tissue | Soft animal tissue | Hard animal tissue | Fungi | Bacteria | Hard samples | Soft samples |
| Leaves, seeds | Stool, muscle, skin | Bone | Mushrooms, mold | Bacteria | Rocks, minerals, soil, cement, plastics, electronics | Pharmaceutical tablets |
| Ball Mills | |
| 8200 Planetary Ball Mill | | | | | | X | X | | | As small as 50 g | Up to 225 g | X | | X | X | |
| 8000M/8000D Mixer/Mill | | | | | | X | X | As small as 0.5 g | X | Up to 25 g | | X | X | X | X | |
| 5120 Mini Mixer/Mill | | | | | | X | X | Up to 1 g | | | | | X | X | X | |
| Bead Beaters | |
| 2010 Geno/Grinder | X | X | | X | X | | X | X | X | X | | X | X | X | | X |
| 1600 MiniG | X | X | | X | X | | X | X | X | | | X | X | X | | X |
| 1200 GenoLyte | X | X | | X | X | | X | X | | | | | X | X | | X |
| Cryogenic Mills | |
| 6875/6875D Large Freezer/Mill | X | X | X | X | X | | | As small as 0.1 g | X | Up to 100 g | | X | | X | | X |
| 6775 Small Freezer/Mill | X | X | X | X | X | | | 0.1 to 5 g | | | | | X | X | | X |
| CG-900 Cryo-Blade | X | X | | | | | | | | X | Up to 1 kg | X | | X | | |
| Ring and Puck Mills | |
| 8550 ShatterBox | | | | | | No plastics or electronics | X | As small as 2 g | X | X | Up to 150 g | X | X | X | X | |
| 8530 ShatterBox | | | | | | no plastics or electronics | X | As small as 2 g | X | X | Up to 150 g | X | X | X | X | |
| | | | | | | | *Small = up to 5 g / Medium = 5 - 10 g / Large = 10 - 100 g / Extra-large = greater than 100 g |
| | | | | | | | *Bead beater sample size is measured in volume (mL) rather than mass. |
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