The Storage Plates in Our Lives
Storage plates, often called Deepwell plates are the ‘Go-To’ solution for the storage, handling and transportation of samples and compounds. They are typically produced in a range of Polypropylenes which offer good chemical resistance, but where lower grade material or ‘Non-virgin’ polymer has been used they can leach extractible elements from the storage plate wall which may provide background noise to your analysis.
The great advantage of storage plates over tubes is the ability to store a large number of samples in a small area, the footprint of which has been defined by the American National Standards Institute, (ANSI) and the Society for Laboratory Automation and Screening, (SLAS). Compliance with these definitions ensures you can be confident that the Storage plate is suitable for use with robotic handling, plate readers and plate handling devices.
Storage plate formats are spilt into two distinct families. Square wells that allow greater well volume and round wells that aid contents mixing in the well. A further variable in storage plate design is the profile of the well base. Commonly, Square Well Storage plates have ‘V’ shaped bases that helps maximise sample extraction, whilst Round Well Storage plates normally have a ‘U’ shaped base that aids mixing. Irish Life Sciences (ILS) are able to offer both well shapes plus some square well storage plates with ‘U’ bottoms.
The height of storage plates is normally influenced by the well volume/shape relationship.
Shallow well storage plates with a well volume of 360ul or 400ul would typically have a height of just under 15.0mm whereas deepwell storage plates can go up to 44.0mm and hold 1.0ml in round well format or 2.0ml in Square well format. Common exceptions to this are low-profile storage plates that are often in the 1.0ml to 1.6ml range and have a height between 24.0mm and 33.0mm. Some manufacturers, including ILS produce a 2.0ml round well storage plate with a height of 44.0mm known as a common wall storage plate.
The number of wells in a storage plate is the final influence on well volume and height. The most widely used storage plates have 96 wells in either square well or round well format, but the range of plates available includes 24, 48 well or 384 well and exceptionally 1536 wells for high throughput screening. ILS have 4.6ml, 48 well and 10.0ml, 24 well storage plates in their range.
Round well storage plates can come with a raised rim to reduce cross contamination and to facilitate strong heat-sealing performance or rimless round well storage plates are available where sealing is not so important, or the storage plate is required to hold glass vials.
All storage plates will have an Alpha-Numeric grid reference along the top and side to aid sample processing. Opacity of the storage plate is influenced by the polypropylene used by the moulder and is not an indicator of material purity. At ILS we use a medical grade polypropylene to guarantee consistency and performance to the highest standard.
Other often overlooked but critical features of a deepwell storage plate are elimination of moulding gases trapped in the wells that increase the potential for leaks and that the plate is flat to ensure sealing performance for storage and minimum evaporation. Storage plates also have a requirement to be stackable for use with robotic applications.
Higher quality storage plates will be moulded in clean rooms using a polypropylene with minimum extractable elements. They will have been tested on LCMS/GCMS equipment to certify that the storage plate is suitable for use on Mass Spectometers without extra peaks in the chromatogram unrelated to the expected analytes.
Here at Irish Life Sciences we are proud of our medical device certified cleanrooms where we mould our storage plates, ensuring they are DNase/RNase free. We use the latest technology in our mould design to ensure we provide consistent, competitive storage plates moulded in medical grade polymers that have been tested on Time of Flight Mass Spectrometers.