Shearing protocols differ between instruments. The current DNA shearing protocols are published on our web site. Click here and follow the link “DNA Shearing” for a protocol that is related to your specific Covaris instrument type for the desired fragment size.
What are the DNA fragment sizes I can get using Covaris instruments?
Covaris instruments can provide tunable DNA fragment sizes from 150 bp to 5kbp. Random shearing with Adaptive Focused Acoustics™ (AFA) energy generates a log normal distributed DNA fragment profile. We provide protocols for the most commonly required DNA sizes. Click here and follow the link “DNA Shearing” to see information on instrument specific DNA fragment sizes. Typically, sizes between the defined protocols may be achieved by increasing the time of the treatment of the nearest size DNA fragment (upper side).
How can I shear genomic DNA into fragment sizes larger than 5 kb?
The single use g-TUBE can be used to shear DNA into large fragment sizes ranging from 6 kb to 20 kb using a bench top centrifuge. Click here and click on the link “g-TUBE User Manual” for the current settings required to obtain your desired fragment size.
We have 300bp DNA which we want to shear to 150-200bp. Can we use the recommended protocol?
Random DNA shearing generates a log normal distribution of fragments. The smaller the size of the input DNA, an exponentially higher amount of energy is required to fragment it to the desired smaller size range. The relationship between size and energy is demonstrated in the figure below. When starting with an input sample containing large fragments of DNA, less energy is required to shear those large fragments randomly to a desired average fragment size. When starting with a smaller input fragment size, more energy is required to shear randomly and generate a distribution of fragments around a desired average fragment size.
Our recommended protocols for shearing genomic DNA as starting material require a more than tenfold larger input starting material than the desired fragment size. When the difference between the size of DNA starting material and desired fragment size is small, increasing the AFA treatment time but maintaining all other AFA parameters is recommended. For example, on the M220 instrument using a microTUBE-130 to shear gDNA to 150 bp, treatment time is 330 sec; if using 300 bp DNA as starting material for the same size, you will need to increase shearing time beyond 330 sec. Please run a time course with 10% incremental steps, and check the results on the Bioanalyzer.
Relationship between DNA fragment sizes and total energy needed.
I do not see any settings for the fragment size I am interested in, but I see settings for size ranges a bit over and a bit below what I am interested in. How can I optimize settings to get the size range of interest?
You should look at the settings that bracket the DNA fragment size of interest. Take the treatment conditions for the larger fragment size and increase the treatment time until the desired fragment size is reached. Conversely, you can take treatment conditions for the smaller size fragment and decrease the treatment time.
Why does the size distribution of fragments seem to get wider with increasing size range?
The scale on an electropherogram generated by the Agilent Bioanalyzer DNA chip is logarithmic, hence the shape of the peak. A peak at 2000bp, with the same base width in seconds as a peak at 500 bp, will cover much wider bp range because of the logarithmic scale. Below is a picture of electropherogram of the 500bp DNA fragment and the same data shown using a linear scale.
I have an Illumina protocol for creating 400bp fragments that uses T6 round bottom glass tubes. What alternatives are recommended?
Covaris has developed DNA shearing protocols using a microTUBE-500 that generates an equivalent DNA fragment size distribution as the one generated in T6 tubes. These protocols are available for all Covaris focused-ultrasonicators. Click here and follow the link “DNA Shearing” for the latest information.
Aside from the phosphodiester bonds, are there any other bonds broken during processing of my samples with the Covaris AFA?
To date there has not been a study to show the effect of acoustic fragmentation on the bonds within the DNA molecule. Indirect evidence from billions of bases sequences so far indicate to a great extent that only phosphodiester bonds are broken during AFA fragmentation of DNA, generating a population of blunt and overhangs of varying lengths which are easily repaired during the initial steps of library preparation.
In what buffer type can I shear my DNA?
We recommend Tris-EDTA pH 8.0 buffer (TE) to give consistent results for a broad range of DNA fragment sizes.
Can I use the Covaris instrument to fragment RNA? If so, what conditions should I use?
Yes, it is possible to fragment RNA using Covaris AFA technology. To fragment mRNA or total RNA into 200nt fragments click here and follow the link for “RNA Fragmentation” to find instrument specific protocols.
Can I use the published protocols to shear PCR amplicons?
Yes, the PCR amplicons can be fragmented using standard protocols as long as the size difference between starting material and desired fragment size is tenfold. When the size difference is smaller the treatment time needs to be adjusted. We recommend running a time course experiment to determine the length of treatment required. As a rule of thumb, if the size of your starting material is within the size range of the generated DNA fragments, you need to extend the treatment time (e.g. if you are trying to get DNA fragments with a mean size of 200 bp the range of fragments that are generated is between 50 and 700 bp).
Does the DNA source have an effect on the shearing conditions and results?
The Covaris AFA random fragmentation is a DNA source independent process. The protocols on the Covaris web site were developed using human, lambda and E. coli genomic DNA. Shorter lengths of starting material may require a longer treatment time to reach the desired fragments sizes.
What is the minimum concentration of input DNA for the g-TUBE?
The g-TUBE has been tested with DNA input as low as 100 ng. For lower input, we recommend to reduce centrifugation speed if necessary.
Can I use a microcentrifuge tube to shear the DNA?
No, the sample vial is a critical component of the acoustic circuit of the Covaris AFA process; the sample vessel material, thickness, geometry and the solution in the vessel all play an important role in this circuit. Following the Covaris recommended protocols and using the appropriate Covaris sample vessels will provide the optimal results. This document illustrates the dramatic effect on thermal control of using a microcentrifuge tube instead of a microTUBE.
Can I use microTUBE or miniTUBE for DNA storage?
No, microTUBE or miniTUBE should not be used for storage, and samples should be transferred after processing.
I notice a fiber inside the microTUBE/milliTUBE. What is the purpose of this fiber, and should I be worried about contamination of my samples from this fiber during treatment?
The fiber inside the tubes serves a dual purpose. The first is providing nucleation sites for inertial cavitation. Cavitation is a process where a bubble in the liquid rapidly collapses creating a microjet that fragments the DNA. The second purpose is to allow for efficient mixing of the sample during processing. The acoustic fiber is thoroughly cleaned during the manufacturing process before being inserted inside the tubes and is free from organic contaminations.
Which centrifuges are compatible with the g-TUBE?
– Eppendorf MiniSpin plus
– Eppendorf Model 5415 R with temperature set at 30° C
I am not getting consistent results when shearing DNA. What might be the reason?
Inconsistent results might be caused by several different factors; however there are few important things to check first:
Sample volume: Each consumable has been optimized for a specific sample volume in order to allow optimal performance. For example, the presence of large headspace allows for the occasional formation of an air gap in the tubes, disrupting the consistent fragmentation of DNA to the desired size range. Click here and follow the link “DNA Shearing” to see information on instrument specific recommended sample vessels for different volumes.
Water level: The water level is critical for DNA shearing. Not only does the water allow for the acoustic energy to couple from the transducer into the tube, it is also important in keeping your sample at the appropriate temperature during processing and minimizing vibrations which could lead to glass tube breakage. Exact water levels to follow are published for each instrument and consumable, click here and follow the link “DNA Shearing” for the latest information.
Water bath temperature: Water temperature should be closely controlled and matched to the application. Warmer temperatures promote less forceful collapse of acoustic cavities within the sample fluid, causing a shift toward larger mean fragment size, therefore the water bath temperature during DNA shearing should be tightly controlled.
Degas level of water: For S, E and LE- series instruments, insufficient degas levels within the bath may result in less efficient acoustic coupling and thereby shift the mean fragment size. System degas pumps should be run in advance and during AFA treatment. Prior to running a process the water bath should be degassed for at least 30 min to one hour, until the “degas” indicator in the SonoLab software can be checked without error.
Water purity: Foreign materials such as algae and particulates may scatter the high frequency focused acoustic beam, resulting in a shift to larger mean fragment size. Bath water should be pure distilled or DI water, changed daily or cleansed by a Covaris Water Conditioning System.
I am not getting the expected DNA fragment sizes. How can I check whether the instrument is working properly?
To check whether the instrument is working properly we recommend using the Covaris DNA Shearing Verification Kit (PN 520120). The user manual is available here.
When analyzing DNA fragments on the Bioanalyzer I am noticing tailing or even a split peak. What is the probable cause?
Loading too much DNA on the chip can distort the peak causing split or tailing. The split peak or shoulder on the right hand side of the peak can also be caused by an occasional formation of an air gap in a microTUBE or milliTUBE. This will result in partitioning of the liquid within the tube and thus the sample will not receive uniform acoustic treatment. As a result larger DNA fragments are observed in the upper region of the electropherogram. To avoid the air gap formation the correct sample volume for the tube type must be used and care should be taken to avoid introduction of air during pipetting.
You can also use Covaris Centrifuge microTUBE Adaptors (PN: 520059 or 500406) to remove any air bubbles introduced during pipetting of the sample into the microTUBE. This reusable adapter fits most bench top microcentrifuges.
When analyzing DNA fragments on the Bioanalyzer I am noticing a small peak near the lower marker. What is the probable cause?
The extra peak can be caused by the presence of RNA in the DNA preparation. The RNA can be sheared similar to DNA into small fragments. However the single stranded RNA runs faster than DNA fragments of the same length. If you are performing PCR prior to shearing, the smaller peak might also indicate primer dimer formation, an artifact of the PCR reaction not generated by shearing.
I followed settings provided in the DNA Shearing Quick Guide for 300bp, but my distribution is centered on 320 bp on a High Sensitivity Bioanalyzer chip. Why is this?
Mean DNA fragment size distributions published in Covaris DNA Shearing Guide are based on electropherograms generated from the Agilent Bioanalyzer with DNA 12000 Kit (cat# 5067-1509), with the exception of the 320 µl microTUBE-500 protocol (High Sensitivity DNA Kit, cat# 5067-4626). DNA fragment representation will vary with analytical systems, please carry out a time course based on settings provided in this document to reach desired fragment size distribution. Please see this document for an illustration.
When I check my sheared samples on a gel, the smear profile looks different to the size range you indicate on your protocol. Why is that?
The smear profile on a gel is dependent on the concentration of the loaded DNA sample, as well as the staining technique that is used. Overloading the gel will give an impression of a wider distribution. Also, staining the gel after the electrophoresis will avoid the gradient formation of Ethidium Bromide.
How should I collect adherent cells and perform sample quantification?
There are a number of different methods that can be employed to quantify the number of adherent cells. Typically, one can culture an additional plate, trypsinize the cells, followed by counting. The counts should be consistent with the other culture plates started at the same time.
Why do I need to run a fixation time course? What cell types is it most critical for and why?
Fixation is not only cell line dependent, but it is also epitope dependent. Not all cells fix at the same rate, therefore, it is imperative to carry out both a one-time fixation and shearing time course to establish a protocol for cell lines and tissue types. Importantly, certain proteins can be quite sensitive to formaldehyde fixation resulting in conformational changes from over-fixation that render them unrecognizable by an antibody.
Why is the methanol-free formaldehyde provided with truChIP kits recommended over other fixing solutions?
Many formaldehyde reagents contain methanol as a stabilizing agent to prevent oxidation and polymerization. Based on our evaluations, we have shown that the presence of methanol leads to the generation of large molecular weight chromatin complexes resistant to shearing.
Why is the fixation time in the Covaris truChIP protocol so short?
In stark contrast to Covaris AFA, bath and probe sonicators utilize up to 150× more energy. As a result, these other methods demand longer fixation times in order to minimize damage to the chromatin. Covaris AFA is a more efficient and gentle mechanical shearing technology that does not require long fixation times.
Why do we need to run a shearing time course if we have already done ChlP before?
Unfortunately, not all cells shear to the same size range at the same rate. As a result, Covaris recommends users to carry out a shearing time course to empirically determine the optimal treatment conditions. For ChIP-seq, it is important to optimize the chromatin shearing size range to be compatible with the selected library preparation kit and sequencing platform. For Illumina platforms, it is recommended to shear chromatin to an average fragment size of 200-250 bp with a distribution up to ~700 bp.
What type of cells can truChIP kit be used for?
truChIP has been successfully tested with hundreds of mammalian cells lines by laboratories across the world. The truChIP kits are considered universal sample preparation kits guaranteed to work with all mammalian cells.
What is the lowest cell inputs that have been tested?
The truChIP ultra-low cell (Covaris PN: 520156) chromatin shearing kit has been used with as little as 10,000 cells.
I want to process 50M cells/sample–is it possible?
Yes, our milliTUBE–1 mL with AFA fiber (Covaris PN: 520135) can accommodate up to 30 million cells. Additionally, one can use the milliTUBE–2 mL (Covaris PN: 520132) for samples with higher inputs up to 60 million cells. Please note: the milliTUBE–2 mL is only compatible with the S220 and E220 platforms.
Does Covaris provide a protocol for tissue ChIP?
Yes, Covaris provides a truChIP kit (Covaris PN: 520083) for processing tissue masses within the range of 18-150 mg. To review this sample prep workflow, please click here.
Is it possible to fragment native ChIP using a Covaris?
Because the energy can be tightly controlled, native ChIP sample prep can be performed using AFA. Please contact us for further guidance on this particular application.
Can you simultaneously lyse and fragment in one tube?
Generally, it is not possible to lyse and shear chromatin at the same time in the same tube. One step methods require high energy processing with high detergent concentrations. The yield of those methods tends to be significantly lower than two step methods. For very low cell numbers, it is possible to do a one-step lysis and shearing as in our truChIP ultra low cell chromatin shearing kit.
May I use my own buffers and reagents?
Most chromatin sample preparation and shearing buffers were developed and optimized for use with bath or probe sonicators. Since Covaris AFA is a more advanced technology, off-label buffers are not compatible with Covaris AFA. Therefore, we strongly recommend customers to use the buffers provided with the truChIP kit since they have been validated with Covaris platforms.
May I combine your protocol with my other commercial protocols?
The truChIP kits are compatible with downstream IP protocols. Covaris provides the formulation of the buffers to ensure the IP step can be performed with any homebrew or commercial IP kit. For example, the truChIP chromatin shearing reagent kit shearing buffer for use with cells contains 1 mM EDTA, 10 mM Tris-HCl pH 7.6, 0.1% SDS.
How does having reduced SDS concentrations help with the Covaris kit?
Reduced SDS concentrations enables the utilization of more sheared chromatin in each IP. Additionally, SDS is a potent solubilizer. Accordingly, shearing with high concentrations of SDS can solubilize a significant amount of the desired epitope.
Is there a required RNase treatment?
Covaris recommends RNase treatment because the presence of RNA can potentially skew the smear analysis performed on the Bioanalyzer and agarose gels.
Why am I not seeing a gradual reduction in fragment size distribution as I shear my samples?
There are a few possibilities why no shearing is observed:
The cells were processed using reagents and protocols not optimized for use with AFA
The cells are being severely over-fixed
The crosslinked sheared chromatin has not been reversed or purified properly for DNA size range analysis
I optimized protocols for a cell line and now observing inconsistent shearing results. Why?
To ensure consistent results are achieved, Covaris recommends using the truChIP kit and to keep the cell numbers within the range outlined in the protocol. Any modifications made to the buffers and/or reagents provided, or deviations in the protocol, may lead to inconsistent shearing profiles.
Why did my IP fail?
IP can fail for a myriad of reasons. Some of the most common ones are:
Over shearing resulting in epitope damage
Fixation was not optimized for the protein of interest–the crosslinking was not sufficient
Incorrect IP buffer that has not been optimized for use with the selected antibody
Is it true that the fixation time cannot be reduced if a target of interest is not abundant?
No, the target abundance is independent of formaldehyde fixation–there is no direct correlation between fixation time and epitope abundance.
I have a large protein complex. What methods are recommended for these sample types?
For protein complexes, depending on the proximity of the protein of interest to the DNA, Covaris recommends the use of a dual fixation strategy. Specifically, this involves fixing proteins to proteins first with DSS, DGS, and DMA followed by fixing the proteins to DNA with formaldehyde.
If I fix shorter less/time, will I lose some downstream sensitivity?
Since fixation is cell line dependent and epitope dependent, it is certainly possible that the fixation might be too little or too much which can affect IP efficiency. Thus, this is why it is essential to carry out dual time course studies. Additionally, we recommend running a Western blot to check the epitope integrity during the shearing time course.
What is the average processing time per sample using truChIP?
Unfortunately, not all cells shear to the desired size with the same treatment time. Therefore, Covaris recommend that you carry out a fixation and a shearing time course to determine the optimal conditions.
Why do I need to control the temperature?
Formaldehyde fixation is reversible with temperature. If temperature is not controlled during chromatin shearing, undesired reverse crosslinking may occur leading to epitope loss.
Specifically, how do the duty factor (DF), power, and duration impact the fragment length?
For chromatin shearing using truChIP, Covaris has already optimized the duty factor (DF), peak incidence power (PIP), and cycles per burst (CPB). Therefore, the user is only responsible for optimizing the shearing time for the cell line or tissue sample.
May I use the truChIP kit with the M220 focused ultrasonicator?
Yes, all Covaris platforms are compatible for use with truChIP kits.
Yes, Covaris provides the milliTUBE–2 mL which can be used to shear chromatin in 2 mL volumes on the S and E-series instruments only. By using these tubes, one can double the number of cells and volume. For sample treatment settings, the duty factor (DF) will be doubled (compared to 1 mL protocol) and the processing times will increase.
What settings should I use on the Covaris for ChIRP/Hi-C, etc.?
ChIRP and Hi-C protocols have not been optimized in-house, but we do have customers who are using it. Please contact us for further guidance on this particular application.
Where can I find protocols for FFPE nucleic acid extraction?
A list of our current truXTRAC FFPE extraction protocols are published on our website. Click here and follow the link “FFPE Nucleic Acid Extraction” for a protocol that is related to your specific requirements.
Can I extract RNA or total nucleic acids using truXTRAC FFPE kits?
Yes, truXTRAC FFPE kits are available for RNA and total nucleic acids. Please look at our product page for further information.
Can I extract proteins using truXTRAC FFPE kits?
Currently extraction of proteins from FFPE tissue is under development. We are continually developing our protocols, so please check the product page on our website, under protocol tab, for the latest information.
Are the truXTRAC FFPE kits xylene-free?
Yes, Covaris Adaptive Focused Acoustics technology (AFA) allows for active paraffin removal in aqueous buffer, compared to the less efficient passive paraffin removal, which uses organic solvents.
What tissue sample types can be used?
FFPE sections mounted on slides, scrolls or cores are compatible with the truXTRAC FFPE protocols.
What is the maximum sample size for use with FFPE truXTRAC protocols?
The protocols are optimized for sections up to 25 µm in thickness and cores up to 1.2 mm in diameter.
What collection tools are recommended for sampling slide-mounted FFPE sections?
FFPE tissuePICK (PN: 520163) and FFPE tissuePICK Forceps (PN: 520164) should be used for FFPE sections ranging from 4 – 10µm in size. FFPE sectionPICK (PN: 520149) should be used for FFPE sections ranging from 7 – 10µm in size. The FFPE sectionWARMER (PN: 500403) is also available to facilitate collection using the FFPE sectionPICK. For more information on how to use these sample collection tools click here.
Why is my DNA/RNA yield low? How can I improve my yield?
Low yield might be caused by several different factors such as;
Low tissue to wax ratio in FFPE section: Excess paraffin will adversely affect the yield and quality of DNA and RNA extracted from FFPE tissue. We strongly advise trimming off any excess paraffin before sectioning a FFPE tissue block, or after the section has been cut from the FFPE block. A ratio of 80% tissue to 20% paraffin, or higher, is ideal. Repeat the procedure using additional sections until desired yield is achieved. In your initial use of the truXTRAC FFPE kit, use FFPE blocks that have been well characterized for yield and quality.
Insufficient tissue input: Increase FFPE tissue section thickness or use more sections up to 5mg total weight.
Proteinase K stored above recommended temperature or expired: Repeat the procedure using fresh Proteinase K. Always store Proteinase K solution at -20°C after resuspension.
If using bead purification low DNA yield may also be caused by;
Incorrect amount of beads were added: Ensure beads are resuspended well by vortexing beads thoroughly before each use.
Binding was incomplete: Make sure the correct reagent volumes were used and mix well before the 56°C incubation.
Beads lost during pipetting steps: Slowly draw up the supernatant into the pipet tip to not disturb the beads. It is normal for beads to stick to the pipet tips during the elution step, this has no effect on yield.
Why do I have no DNA/RNA?
Ensure that the protocol steps have been closely followed, including ethanol addition to wash buffers and mixing of the Proteinase K with the sample on the Covaris instrument. Proteinase K buffer contains glycerol, and may fall to the bottom of the microTUBE, therefore mixing is essential.
The concentration of DNA/RNA is too low, what could be the cause?
Elution volume may be too high. Repeat the procedure using lower elution volume (50 µl minimum volume is required for DNA and 20 µl for RNA). Alternatively, concentrate samples using ethanol precipitation or other means.
When following the FFPE DNA protocol with bead purification I notice clumping of magnetic beads during wash steps. Is this a problem?
Some clumping of magnetic beads may occur with specific FFPE blocks. Bead clumping will not affect the yield or purity of the DNA. If bead clumping is severe enough to clog pipette tips reduce the input sample amount.
Magnetic beads are sticking to the pipette tips during elution whilst following the FFPE DNA bead purification protocol. Will this affect my DNA yield?
Some sticking of magnetic beads to pipette tips may occur with specific FFPE blocks. Magnetic beads sticking to pipette tips during elution will not affect the yield or purity of the DNA. If bead sticking is severe enough to clog pipette tips reduce the input sample amount.
Why does my DNA not perform well in downstream applications such as qPCR?
DNA in FFPE sample blocks could be severely cross-linked or degraded, therefore ensure amplicons are designed to be as small as possible (<100 bp). DNA isolated using Covaris AFA technology is of the highest possible quality. Some FFPE sample blocks may be too degraded or cross-linked for some applications.
[av_toggle title='The DNA fragment size is too large when following Option A of the FFPE DNA protocol. What is the cause of this?' tags='Troubleshooting']
Too much emulsified paraffin in the sample absorbs some of the acoustic energy and will adversely affect DNA shearing efficiency. Trim any excess paraffin from tissue blocks before proceeding with the protocol. We recommend running a time course for DNA shearing (Step 7) to increase the treatment time by 30 second steps.
[av_toggle title='Which Covaris ultrasonicators are compatible with truXTRAC FFPE protocols?' tags='Instrumentation & Accessories']
All Covaris AFA instruments are compatible with truXTRAC FFPE kits. However each instrument will require specific accessories that may need to be purchased separately. Please look at the product page for detailed information.
Instruments & Software
How do I convert a method developed on an S2 or E210 for use with SonoLab 7?
What happened to Intensity (as employed in previous versions of SonoLab)?
In SonoLab 5 or later, Intensity has been replaced by Peak Incident Power (PIP) to better represent acoustic treatment conditions. In the S2 and E210 instruments, Intensity served as a dimensionless proxy for the power emitted from the transducer during each acoustic burst, with Intensity 10 equivalent to approximately 350 Watts of Peak Incident Power. New generation instruments operating under SonoLab 5, 6, 7, and 8 are capable of delivering up to 500 Watts of Peak Incident Power (depending on the instrument). Rather than invent a new dimensionless scale, Covaris chose, in SonoLab 7, to specify Peak Incident Power in true Watts.
Why do I need to change water in the tank every day?
Purity of the water in the bath is very important for the proper acoustic coupling. When applying acoustic energy in rate-limited applications, foreign material such as algae and particulates may scatter the high frequency focused acoustic beam, resulting in a shift to a larger mean fragment size. Bath water should be deionized water, changed daily unless continuously treated by the optional Covaris Water Conditioning System (available for S, E, and LE instruments). Click here to learn more about the WCS System.
Besides daily changing the water in the bath what are the other maintenance recommendations?
For all instruments, except the M220, the water bath and the degassing lines should be rinsed once a month with a 10% bleach solution. Fill the bath with the 10% bleach solution, lower the transducer and run the degassing pump for a few minutes. Raise the transducer and empty the tank. Lower the transducer and run the pump for 5-10 sec to empty the lines. Fill the water bath with fresh water and repeat the procedure. The ME220 bleach protocol is run using the fill bottle according to the procedure in the user manual.
I have the Covaris Water Conditioning System. What kind of the maintenance should I perform?
The Water Conditioning System (WCS) automatically circulates water through a particulate filter and ultraviolet (UV) sterilizer to ensure that water remains clean and free of algae growth for up to one month. When the system runs continuously, it maintains the proper water quality required for optimum performance of the transducer. Without the WCS, proper water quality is maintained by daily changes of the water in the water bath. Once a month, the water tank should be cleaned with a bleach solution as described above. IMPORTANT: disconnect the hoses to and from the WCS when performing the bleaching procedure. DO NOT circulate bleach solution through the WCS. The UV lamp and filter should be replaced once a year as indicated by the hour meter on the front of the WCS. Instructions for this can be found in the user manual.
Why is it so important to degas the water in the tank?
Water in the tank (not in the chiller) serves as a coupler in the acoustic circuit. The need for clean and degassed water cannot be overstated. Poor water quality may dramatically impede the high frequency energy transfer. Insufficiently degassed water will readily scatter acoustic energy. The same can happen when water is contaminated with small particles. Keep in mind that at high frequency the acoustic energy may be scattered by dissolved gases and vapors present in water at standard atmospheric conditions as well as by particles suspended in water. Degassing is not required for the M or ME instruments.
Can I add algaecide to my water bath?
No, algaecide should not be added to the water in the tank to avoid formation of the aerosol containing algaecide during the AFA treatment. However, you can add algaecide to the water in the chiller since the water is circulating through a stainless steel loop immersed in the water bath.
When I am done using the Covaris system, how should I properly shut down the instrument?
To shut down the instrument, turn off degassing and raise the acoustic assembly to lift the transducer out of the water, and empty the water bath. Place the tank back on the instrument, and turn on the degas pump for 5 seconds to empty the remaining liquid dry it with a lint-free cloth and place it back into system.
What is AFA-grade water?
It is water meeting AFA-grade specifications (ASTM Type III or ISO Grade 3) such as Covaris #520101. AFA-grade water is recommended for Covaris Focused-ultrasonicators to properly complete the acoustic circuit.
The chiller is for some reason taking over an hour to chill the water bath on my S220. What could be the cause?
There could be several reasons why the chiller doesn’t efficiently cool the water bath. First, you should check the fittings – are they firmly connected? Are the hoses free of kinks? Are the hoses being pinched? Have the length of the hoses been increased? Are any particulates present in the chiller water that can cause clogging? Has chiller set point been changed? Is the water (or fluid) level in the chiller adequate; low level results in inefficient chilling?
I have a VWR chiller that came with the Covaris instrument. I can’t change the temperature on the chiller control panel. What should I do?
The reason why the current settings cannot be changed is because the local lockout feature on the controller has been activated. The screen is reading, “LLo.” To unlock the controls, press and hold the Select/Set Knob for 10 sec. The screen will read, “CAN,” and the setting can now be modified.
How can I convert a method from one model instrument to another?
What is the latest version SonoLab 6 software (for E and LE instruments)?
SonoLab 6.2.8 was the last version of SonoLab 6 software released. SonoLab 6 is technically obsolete and has been replaced by SonoLab 7.3. The SonoLab 7 platform features improved error recording and the addition of history files. The same settings are used for protocols in both versions of software. If you have questions or concerns about upgrading, please contact firstname.lastname@example.org.
6.2.8 (can be replaced by 188.8.131.52)
Can AFA water be cooled in advance to speed up the preparation time?
AFA water must be degassed prior to cooling. Degassing is very ineffective at colder temperatures. Covaris does not recommend chilling water in advance. The Water Conditioning System is an optional accessory that can be used to keep water clean so that it does not need to be changed more than once a month. It is available for S, E, and LE series instruments. Please contact your local sales representative for more information.
How can I be sure that the degas pump is running?
The degas pump should be audible when running. Additionally, you can check for very small bubbles coming from the degas outlet tube. If bubbles do not appear to be coming out of the outlet tube, the intake tube may need to be cleaned. The intake tube has 6 very small holes where the water is pulled in. These can be cleaned by wiping down and using a narrow gauge wire to poke through any build up that is blocking the holes. If this does not solve the problem, your degas pump may need to be replaced. Please contact email@example.com if you believe the pump is not working. M and ME instruments do not contain a degas pump.
Our facility is prohibited from using bleach. Is there an alternative that can be used?
Hydrogen peroxide is a substitute that can be used to clean the tank and internal fittings of the instrument. This should approximately be 1.5% hydrogen peroxide solution. In E/LE series instruments with a 5L water tank, this is 1L of 8% hydrogen peroxide – the most commonly available concentration. For the S-Series water tank, 1/3 of this amount should be used.
If the maintenance or check flow light appears on my WCS, how do I turn this off?
The Maintenance light indicates that the filter and bulb need to be replaced (this is recommended annually). After replacement, the alert can be reset with the button inside the cover. See the WCS user manual for additional information.
The Check Flow light indicates that the pressure is building up and water flow is restricted. The hose connections may need to be reset if they are not seated properly. If this does not solve the problem, the filter may need to be replaced because it has become blocked.
Covaris provides tools and technologies to improve pre-analytical sample preparation, enable novel drug formulations, and manage compounds in the drug discovery process.