| 1. | | Can the Dispensette® dispense _________? |
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With the addition of the Dispensette® Organic and new Dispensette® HF, the Dispensette line of dispensers can now dispense nearly any laboratory chemical. The notable exceptions are:
NaN3 (sodium azide): Found in many biology labs, and used as a preservative for buffers. It removes the fluorine in PFA, FEP, Teflon and other Teflon-like materials. It also attacks these materials in almost any other bottle-top dispenser using these materials. You should consider our seripettor® bottletop dispenser, which is resistant to sodium azide. Because sodium azide is often used in solution with other chemicals, confirm the compatibility of all components of the liquid before use.
Br (Bromine): Bromine is too dense to be dispensed by a Dispensette®.
Carbon Disulfide (CS2): Carbon disulfide presents an explosion risk, and should never be dispensed by a Dispensette®.
Suspensions: The Dispensette should not be used to dispense liquids that contain particles, as they will clog or damage the insides of the instrument.
Physical Limitations: Any liquid that has a density of over 2.2 g/cm3 can not be dispensed by the Dispensette® III or Dispensette® Organic, as it will be more dense than the borosilicate glass filling valve, and the ball will float, preventing it from closing. The Dispensette® HF has an alumina ceramic ball valve. As such, it can dispense liquids as dense as 3.8g/cm3. Some examples of dense liquids the Dispensette® HF can dispense are Bromoform, Dibromoethane and Tetrabromoethane
Temperature of 59 ºF to 104 ºF (15 ºC to 40 ºC) for instrument and reagent. Temperatures of up to 250 ºF (121 ºC) will not damage the Dispensette®, although some of the materials may get soft enough to get damaged by use at these temperatures. The major consideration for hot applications is that liquids dispensed at higher temperatures, like agar, usually are done so because the liquid becomes less viscous at these temperatures. When the liquid cools, these type of liquids can clog the Dispensette®. A customer may try these temperatures, but at their own risk, as it will void the warranty. For dispensing agar, we recommend our seripettor® bottletop dispenser.
Viscosity over 500 mm2/s. Liquids that are too thick will tend to clog the Dispensette®, impair valve function, piston movement, etc.
Vapor pressure over 500 mbar (375 torr) or extremely volatile liquids. Liquids that have a high vapor pressure tend to vaporize inside the dispenser, causing liquid to flow out of the dispenser even when the instrument is not being operated. A common volatile liquid is Acetone (aka “Nail Polish Remover”) which has a vapor pressure of 184 mbar at room temperature, and will work fine.
A chart listing many commonly used laboratory liquids can be found in the BrandTech catalog, or on our website. |
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| 2. | | What is the difference between a Dispensette® III and a Dispensette® Organic? |
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| The Dispensette® Organic has much in common with a Dispensette® III, however there are two major differences. The Dispensette® Organic has a glass piston, rather than a PFA-coated piston. This optimizes it for use with concentrated acids and organic solvents that can interact with the PFA, but makes it less useful for bases. In addition, the valve spring was changed in the Dispensette® Organic to tantalum (from platinum-iridium alloy) to allow it to be used with peroxides, again, at the expense of compatibility with bases. Because of the different construction and chemical compatibility, parts from a Dispensette® III should not be used with a Dispensette® Organic, and vice versa. |
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| 3. | | How should I autoclave my Dispensette? |
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| Anyone who wants to autoclave a Dispensette should read the manual thoroughly. Page 51 specifically refers to Autoclaving. If you do not have a copy, click here for the electronic version. Note: While both gravity and pre-vac are acceptable methods, pre-vac is recommended. |
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| 4. | | What is the purpose of the elastomer ring that came with my Dispensette®? |
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| The elastomer ring should be installed if the Dispensette® is autoclaved. It should not be installed for general purpose dispensing, as it is not resistant to some solvents. Complete instructions are in the manual. |
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| 5. | | Can I use "cold" sterilizers with my Dispensette®? |
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| There are currently several different sterilizers on the market using hydrogen peroxide, either vaporized or as a gas plasma. These instruments are not suitable for the Dispensette® as the platinum-iridium valve spring catalyzes the breakdown of hydrogen peroxide into oxygen and water. Additionally, these systems do not perform well when used with items with long blind lumens, such as the Dispensette discharge tube.
Ethylene oxide or "gas sterilization" can effectively sterilize the Dispensette, but it will shorten the lifetime of the instrument somewhat. As such, it will void the warranty. |
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| 6. | | Can I use liquid solutions to sterilize my Dispenstte®? |
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| While it’s possible to use soaks such as glutaraldehyde to sterilize a Dispensette® for decontamination purposes, the sterilizing agent will form a film between the piston and cylinder, and contaminate the dispensed liquid until it eventually works its way out. |
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| 7. | | How do I clean my Dispensette? |
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| Cleaning instructions are located in the manual. If you do not have a copy, click here for the electronic version. All current Dispensette models disassemble easily for cleaning. |
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| 8. | | What precautions should I take when dispensing sterile fluids with a Dispensette®? |
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| In addition to autoclaving the dispenser, you may want to consider the use of our micro-filter connector, #704495. This filters the air coming inside the bottle to displace the liquid, to keep out bacteria. |
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| 9. | | I just autoclaved my Dispensette® III “Easy Calibration” model, and now it seems to leak. What’s happening? |
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| The housing of the Dispensette® III “Easy Calibration” has a large amount of surface area. If the instrument is not given sufficient drying time in the autoclave, some condensation may collect as droplets just below the housing, on top of the valve block. |
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| 10. | | My Dispensette seems to leak at the base, especially after priming. How do I stop this? |
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| It’s probable that the recirculation tube was not reinserted into the underside of the instrument. This directs liquid down the side of the bottle, to help keep from generating additional bubbles when priming. When absent, some liquid can dribble down the side of the instrument. If you need a replacement, the part number is 8317 and can be ordered from your favorite supplier. |
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| 11. | | I am dispensing hydrogen peroxide with a Dispensette® III, and am having a number of problems. The discharge tube drips, my assays are inaccurate, and when left for a while, the piston begins to rise all by itself. What should I do? |
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| Hydrogen peroxide is a chemical that is catalyzed by the platinum-iridium valve spring in the Dispensette® III. The hydrogen peroxide breaks down into water and oxygen gas. The gas is what is forcing out the liquid, and pushes the piston up. Essentially, the customer is using water for their assay. The Dispensette Organic, with its tantalum spring, should be used with peroxides. |
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| 12. | | The piston of my Dispensette® is moving roughly. What should I do? |
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| Crystals have probably gotten between your piston and cylinder, and are grinding away the piston and seal. If the instrument is operated in this condition, it is possible that the piston and cylinder are scored. Gently remove the piston, and follow the cleaning procedure as described in the manual. Retry the dispenser. The easiest way to avoid this is to clean the Dispensette® at the first sign of roughness. The best way to avoid this is to clean your Dispensette® at regular intervals. Continued use of the dispenser in this condition can destroy it. |
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| 13. | | Are there any precautions I should take when dispensing scintillation fluid? |
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| Many scintillation fluids precipitate in the presence of water. These precipitates can impair the function of the Dispensette®. You should make sure the instrument is completely dry before use. Additionally, in humid climates, it may be necessary to use a drying tube to keep atmospheric moisture from contaminating your scintillation fluid. |
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| 14. | | What is the function of the drying tube? |
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| When a dispenser dispenses liquid, air needs to enter the container to displace the liquid. If the liquid is sensitive to components in the air, for example, water vapor, a drying tube is recommended, so that an appropriate drying agent can remove the water. BrandTech does not sell drying agent, only the drying tube. |
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| 15. | | I lost my manual. Can I get one? |
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| Click here for our full line of operating manuals. |
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| 16. | | I broke my piston or cylinder. Can I purchase a replacement? |
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| Unfortunately, the piston on a Dispensette® is matched to the cylinder to very close tolerances at the factory. This is so that the instrument can have smooth one-handed operation without the need for a seal. However, this makes piston replacement impossible. If you break either your piston or cylinder, call our customer service department, and ask about our repair/replacement exchange program. |
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| 17. | | Why don't you supply all ETFE adapters with the Dispensette® Organic? |
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| Polypropylene is compatible with many solvents. ETFE is much more expensive than PP. If ETFE adapters were supplied with the instrument, the cost would go up significantly, and three our of four of these expensive adapters would not be used by the customer. |
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| 18. | | The cylinder of my Dispensette® doesn’t fill. What is happening. |
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| There are several different causes that could keep a Dispensette® cylinder from filling:
1. The discharge tube and/or SafetyPrime™ valve are not fitted properly. Check to ensure they are attached properly, and that the sealing washers are in place.
2. The filling valve is not tight or the filling tube is not pushed in enough. The filling valve is most often loose because the autoclaving instructions were not followed closely. Recheck the connections.
3. The filling valve is dirty. This case is can be told easily because the Dispensette® piston is difficult to lift, and it gets “sucked back down” when released. Clean the valve. |
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| 19. | | My Dispensette® is drawing up bubbles and liquid? What should I do? |
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| Your Dispensette® has an air leak somewhere. Good places to look are at the junction of the filling tube and filling valve. If it does not make a tight seal, trim some of the tube off, and reattach. Check to see if the filling and discharge valves are tight, and the sealing washers are in place. If the Dispensette was dropped the cylinder may have cracked, or come loose from the valve block (irreparable). Lastly, is there any liquid in the bottle? |
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| 20. | | Can I use my Dispensette® with a bulk chemical container? |
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| Probably, as long as it’s unpressurized. To mount a Dispensette® III or Dispensette® Organic directly onto the ¾” bung of a chemical drum, order part number 704280. A longer filling tube may be required. Order part #704261 for a Dispensette® III or Dispensette® Organic to remotely dispense from the drum. For NOWPak containers, use Catalog number 704284. As each circumstance is different, additional parts may be required. |
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| 21. | | Is a discharge tube available with a Luer Lock fitting? |
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| A discharge tube with a Luer Lock fitting for the attachment of filters can be ordered as order part number 707928. This discharge tube is not suitable for peroxides. Care must be taken while dispensing not to create excess back pressure. |
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| 22. | | Can I use a flexible discharge tube with my 0.05 - 0.5mL Dispensette® III. |
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| Yes, and no. The 1 - 10mL flexible discharge tube (707925) will fit the 0.05 - 0.5mL Dispensette®. However, because of the length of the tubing, dispensing of volumes below 2mL will not meet the accuracy and precision specifications that BRAND publishes. Depending on the application, this may be fine for the user. This also applies to volumes below 2mL on the 0.2 - 2mL Dispensette as well. |
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| 23. | | Can I use my Digital Buret™ III discharge tube on my Dispensette III (or vice versa)? |
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| Yes. The Digital Buret™ discharge tube has a smaller bore at the tip, though, and may cause problems when dispensing large volumes. |
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| 24. | | Why doesn’t a Dispensette® come with a bottle? |
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| The Dispensette® is designed to fit onto most common reagent bottles with the supplied adapters, and many additional adapters are available. By mounting the instrument directly onto the reagent bottle, poured transfer, and associated spilling, is eliminated. Additionally, the likelihood that we would be able to guess your preferred bottle is extremely small. |
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| 25. | | What size adapter do I need for this bottle? |
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| It’s hard to say definitely without seeing the bottle. Most 1 liter and 1 quart bottles in the United States have a 33mm thread. Most 4 liter or 1 gallon bottles in the US have a 38mm thread, as do many scintillation fluid bottles. All sizes of the Dispensette® fit 45mm bottles, and come with adapters to fit 33mm and 38mm threads. Smaller Dispensette® dispensers come with additional adapters for smaller bottles. |
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| 26. | | A performance certificate came with my Dispensette®. Is this the performance for my specific instrument? |
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| The Dispensette® is lot tested for accuracy and precision. They are not provided with individual calibration certificates. |
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| 27. | | What standard does the recommended steam sterilization (autoclaving) procedure reference? |
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| The 250 F (121 C) / 20 minute exposure time protocol used for the Dispensette III and other BRAND products is specified by DIN EN 285. |
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| 28. | | What thread adapter fits my CareFusion saline bottle? |
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| CareFusion saline bottles have a 35mm thread. The thread adapter to fit this bottle is catalog number 704431. |
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If you're having trouble finding the information you want, BrandTech Customer Service is here to help. Call us at 888-522-2726, or if you prefer, contact us online.
