FAQ

How can I order Optimize Technologies products?

Optimize Technologies products can be ordered through any authorized dealer - whether in the United States or worldwide - by phone (800-669-9015 or 503-557-9994), email (orders@optimizetech.com), and online. If you do not have an Optimize Technologies dealer in your region, please contact us to either order directly from our company or for a dealer recommendation.

How late can I place an order for same-day shipping?

Orders placed directly with Optimize Technologies before 12 pm PST on a business day will normally ship that same day if the items ordered are in stock (pending credit approval).

What forms of payment do you accept?

We offer NET30 terms to approved customers with accounts in good standing. We also accept Mastercard, Visa, American Express, and PayPal.

What is the Optimize Technologies return policy?

At Optimize Technologies, our products are fully guaranteed to meet or exceed original equipment specifications and to meet your own demanding expectations. Quite simply, your satisfaction is guaranteed. If you are unhappy with any analytical products you receive from us, please contact the authorized distributor from whom you purchased the item or us.

A Return Materials Authorization (RMA) number must be obtained before any product can be returned to us. The RMA number allows us to properly identify returned goods and to resolve problems quickly and efficiently. Optimize Technologies is not responsible or liable for goods returned without prior authorization. Most returns and exchanges are accepted up to 12 months after purchase. Lamps, however, are accepted for only 30 days. Please contact an Optimize Technologies representative for more information.

How do I know which check valve replacement cartridge to order? 

The middle two digits and the very last digit in the part number of your check valve housing correspond directly to the check valve replacement cartridge you are looking for.

The first middle digit – This number signifies the size of the replacement check valve cartridge.

• 10-3x-02004: 1/32”
• 10-4x-02004: 1/16”
• 10-5x-02004: 1/8”
• 10-6x-02005: 3/16”
• 10-7x-02004: 1/16” (UHPLC pressures)
• 10-8x-02004: 1/16” (Double ball UHPLC pressures)

The second middle digit – This number signifies the type of material the replacement body, ball, and seat are created from.

The last digit –

• 10-xx-02004: All check valve replacement cartridges ending in 02004 are interchangeable between all OPTI-MAX housings (except xx-6x-xxxxx)
• 10-xx-02005: Check valve replacement cartridges ending in 02005 require Extended Flow housings (xx-6x-xxxxx)

Are your check valves self-priming? 

Question:  I read somewhere about some cartridge check valves that are "self-priming." Is this true for OPTI-MAX® check valves? 

Answer:  We've seen check valve manufacturers claim that their check valves are "self-priming". We do not understand this to be possible. 

The check valves found in almost all LC systems are passive flow restriction devices. The ball opens and closes in response to pressure gradients - differences between the pressure before and after the check valve. When the pressure at the check valve inlet exceeds that at the outlet, liquid flows through. When the outlet pressure is higher, the check valve closes.

So, how do "self-priming" check valves entice the mobile phase to flow up the inlet tubing and into the pump head? Nothing. Or rather, nothing different than other check valves.

In our experience, only one thing will cause the mobile phase to flow into the pump head: hydrostatic pressure. It could be positive (generated by elevating the solvent reservoir or applying head pressure within a sealed solvent reservoir using a sparging gas) or negative (a vacuum generated by a priming syringe or by the piston of your LC pump). All a check valve has to do to help is to stay out of the way! You certainly want a check valve that offers minimal resistance to flow in the positive direction (and maximal resistance at all other times), but to say that a passive check valve is playing an active role in the pump priming process is misleading.

Manufacturers say that with their "self-priming" check valves, pump priming becomes a simple matter of dunking your solvent line in the reservoir, turning your dry pump on at 5mL/minute, and putting your feet up while the pump does all the work. Do not follow this advice! You should avoid turning on your LC with a dry pump head. A dry piston dragging back and forth through a dry piston seal will bring liquid up into the head, but it will also cause increased seal and piston wear, causing you to replace seals much earlier than you'd like. Wetting the seal and piston with solvent as quickly as possible will help both components last longer. If you can get liquid to the head simply by opening a purge valve and elevating the mobile phase, great! If not, use a priming syringe to get liquid to the head before you turn it on. Your seal will be far less likely to be damaged during system start-up and will last much longer.

We do not claim that our check valves are self-priming because we think the claim isn’t true and is, in fact, misleading. If you'd like to talk about check valve design parameters that do have an actual effect on check valve performance, please give us a call - we'd be glad to discuss!

Cartridge-type and rebuild-type check valves - which is better? 

Question: Optimize Technologies offers cartridge-type check valves, while some OEMs still use rebuild-type check valves. Which is better, and why?

Answer: For all HPLC pumps we support, we offer a cartridge-based aftermarket check valve system that offers a series of benefits over rebuild-type check valves. Replacing whole assemblies in rebuild-type check valves means throwing out the entire check valve housing and internal components, then installing a new assembly. This is expensive and wasteful. Rebuild kits are more economical, but the procedure is time-consuming and troublesome. Additionally, there is a risk of improper assembly and contamination.

Cartridge-based systems are, therefore, the preferred choice. They offer greater convenience, reliability, and economy, while reducing waste and risk of contamination during installation. Our OPTI-MAX Cartridge Check Valve System offers several other advantages, including a universal cartridge feature, the tightest leak-rate specification available, a choice of materials for the cartridge and ball/seat, and much more.

How long can I expect my Optimize Technologies check valve to last? 

In general, you should be able to get at least 6 months of reliable performance from any check valve. With an Optimize Technologies check valve, you may get a year (or more) of reliable operation. Essentially, your mileage may vary depending on a number of factors, including operating conditions such as average back pressure, salt content of mobile phase, and flow rate.

What do I do with the Agilent 1100/1050 inlet check valve? 

The Agilent 1100 and 1050 both use a solenoid-driven active inlet check valve. This check valve is the assembly you see sitting on the underside of your pump, right where the inlet line runs in. Replacing the entire assembly every time the pump needs to be serviced would become very expensive, so a small cartridge with the ruby ball and seat is replaced instead. While this makes it much more convenient and less expensive, it was not always this way. If you have an older pump and the inlet check valve has never been serviced, there is a good chance you have an active inlet valve, and the entire assembly must be replaced. Unfortunately, this is unavoidable. However, once the assembly has been replaced with the newer version, all subsequent service to the inlet valve can be done by replacing just the cartridge.

What OPTI-MAX cartridge type/material does Optimize Technologies recommend? 

For most applications, we recommend a stainless steel cartridge with a ceramic ball & seat. Ceramic is 1.5 times denser than ruby, and the heavier ball will seat more quickly, especially in lighter solvents.

Exceptions to this recommendation are as follows:

When aggressive organic solvents are to be used, consider PEEK cartridges. Stainless steel OPTI-MAX cartridges are equipped with Kel-F end caps; switch to PEEK in the few cases where solvent compatibility with Kel-F is a concern.

Use PEEK cartridges with PEEK OPTI-MAX housings for biocompatible systems like the Waters 625/626 and Dionex systems.

Use PEEK cartridges when THF is present in the mobile phase. PEEK is uniquely suited for this application, as the material is thick enough to resist softening, and it is well-supported mechanically. We have been running PEEK OPTI-MAX check valves in 100% THF for a year to great success.

Why is there no filter in OPTI-MAX outlet check valves? 

Question: I notice that OPTI-MAX Cartridge Check Valves don't have a filter within the outlet check valve. Why not put a filter in there to catch particulates?

Answer: Some check valve designs incorporate a filter element within the outlet check valve. While in-line filtration is a worthwhile addition to any HPLC, putting a filter within the outlet check valve assembly has two major drawbacks.

First, a filter right above the outlet ball will concentrate particulates in a region where they could cause check valve failure.

Second: the presence of an in-line filter element upstream from the pressure transducer can complicate pressure-based instrument diagnostics. We recommend using an in-line filter under all circumstances, but the best way to accomplish this is to install a separate filter assembly in-line downstream of the pressure transducer.

My HPLC makes a clunking noise. 

Question: I have a "clunking" HPLC (a ten-year-old Perkin-Elmer 250 binary pump). This problem just developed in the last few days -- the "clunk" is not consistent, but develops if the pump is equilibrated at a low flow rate (0.2 mL/min) for a couple of hours and then put back into the operating flow rate (1 mL/min); if equilibrated at 1 mL/min, it takes a longer time (the whole day), but eventually the "clunks" start, albeit sporadically. No degassing problems; seal changed 6 weeks ago; the flow is okay; the separation/current method is okay... could this be the check valves? Or something else? 

Answer: Does this pump have spring-loaded pistons? If you're hearing a pretty loud clunk, our first suggestion is that one of the pistons isn't following the cam consistently. Something is causing it to "stick" temporarily in the fully displaced position, and the clunk you hear is the piston releasing and the base striking the cam. What can cause this, you ask? A too-tight piston seal can do it, as can precipitates on the piston.

But if the pistons are spring-loaded, a spring may need to be replaced. Salt may be more likely to build up at the slower flow rate.  Do you know which piston is clunking? Do you see any flow artifacts in the baseline when the clunking occurs? Our final suggestion is that the clunk could be coming from within the drive assembly itself, caused by a bearing or other mechanical part. At such a point, an in-person diagnosis would be best.

I put in a brand-new piston seal, and it leaked. Any advice?

The way a seal is installed can have a significant effect on how well it performs over its lifetime, or even whether it performs at all. Immediate seal failure is often caused by damage caused during installation. Most installation problems can be remedied with a combination of seal pre-soaking and wetting of all mating components prior to installation.

Another possible cause is a worn piston.  During routine use, a seal and piston will wear together, and occasionally a flat or dull spot will be created on the piston.  When a new seal is installed, the piston still has a worn spot and won’t be flush with the seal, which could cause leaking.  Our advice: replace your piston when you replace your seals.

Piston Seal, Solvent Compatibility Issues 

Looking for information on finding the best seal for your application? Want to know if there are potential interactions between the seal material and the solvent you're using? Consult our Seal/Solvent Compatibility Guide.

What makes a good piston go bad? 

Abrasion! Your piston has a rough life - the piston gets crammed through a pretty tight aperture under high pressure ten, twenty times a minute, and the resulting friction will eventually abrade the piston surface. And if you're using buffers with inadequate piston washing facilities, the abrasive salt crystals will add to the abrasion. At some point, piston wear will reach a stage where the seal can no longer contain the pressure around the moving piston. At that point, the piston needs to be replaced. Signs of wear or trouble include scratches or haziness on the piston surface, flat spots, or other signs of unusual/uneven wear. 

What piston seal material should I choose? 

Optimize offers piston seals in two materials: UHMW-polyethylene (our OPTI-SEAL® brand) and graphitized PTFE (our ITB™ brand). The UHMW-PE material offers increased abrasion resistance and exhibits longer lifetimes in mostly aqueous mobile phases, especially when buffer salts are present. Graphitized PTFE offers broad resistance to most common organic modifiers used in HPLC mobile phases (DMF can cause problems, though). For more specific information on seal/solvent interaction, view our Seal/Solvent Compatibility Guide or contact Optimize Technical Support for a recommendation. 

What role do seal springs and O-rings play? Why are they there? 

Question:  There are seals with springs in them and seals with O-rings. I've even seen several types of springs in some seals. What does the spring do, and how important is it?

Answer:  The function of springs and O-rings in piston seals is to assist in the actuation of the seal at low pressure. When you first start up your pump, the spring force pushes the outer seal wall against the piston, pressing the inner seal wall into the piston to form a seal. As the pressure inside the pump head increases, the hydraulic pressure of the mobile phase takes over seal actuation, and at that point, the spring is just along for the ride. This crossover point can be anywhere from 250 to 400 psi, depending on the seal material and thickness. Of course, the pressure inside at least one of your pump heads is likely to cycle between system and ambient pressure, so the spring still plays a role in keeping the seal actuated at low pressure during normal pump operation.

Which end of the seal goes in first? 

The seal's spring cavity is energized by the hydraulic pressure of the mobile phase. Therefore, the side of the seal with the spring/spring cavity or O-ring should face the high-pressure side. In most pumps, this means putting the seal in the spring-side first into the pump head, although some pumps reverse this orientation by requiring the seal to be pushed closed-side first into a bushing.

I already use a Solvent Reservoir Filter - why would I need an In-Line Filter as well?

Question: I'm filtering my mobile phase after preparation, and I use a solvent reservoir filter. Why would I need an in-line filter as well?

Answer: Running an HPLC pump without an in-line filter is not nearly as negligent as running your car without an oil filter, but the end result will ultimately be the same - increased maintenance and downtime due to damage from particulates. Your HPLC pump will introduce particulates into even the purest mobile phase. As the piston moves back and forth through the seal at high pressure, seal fragments can slough off the seal's mating surface. If you don't use an inline filter, these particulates will clog and/or damage downstream components, such as the injection device and analytical column. Placing an in-line filter between the pump and injection device is possibly the most worthwhile filtration step you can take. Which would you rather replace every one to two months because of particulate clogging - a $500 analytical column, a $5,000 autosampler, or a $10 in-line filter frit?

Is precolumn filtration necessary? 

Question: Is precolumn filtration really necessary?

Answer: Two potential sources of particulate contamination can cause trouble in the region beyond the injection device but before the analytical column. First, the injection device itself can introduce particles from rotor seal wear or from coring vial septa. Second, contamination may be introduced by the sample matrix. Where practical, most of these types of contamination can be addressed in the sample preparation procedure. In cases where additional filtration is required between the injector and column, a low-volume, low-dispersion filter and/or guard column must be employed. OPTI-SOLV Mini Filters and OPTI-GUARD Guard Columns work extremely well for applications requiring precolumn protection.

Should I pre-filter my mobile phase? 

The first and easiest place to prevent particulate contamination is in the mobile phase. Buffer salts, improperly cleaned glassware, microbial contamination, and pre-filtering procedures are all sources of particulates. Solvent manufacturers adequately filter HPLC-grade solvents before bottling, but the glassware they're going into isn’t always clean. Ideally, there should be no need for additional pre-filtering in your laboratory if your mobile phase contains only HPLC-grade solvents, but it’s always better to be safe and use a Solvent Reservoir Filter. Mobile phases prepared with buffer salts or other solid reagents should, however, be filtered prior to use. A 0.2- or 0.45-µm membrane filter is recommended for this filtration step. It is also a good idea to discard the first few milliliters of solvent that pass through the filter.

Should I use a solvent reservoir filter? 

Solvent Reservoir Filters are a useful filtration accessory, providing a first line of protection as the solvent enters the system. They also help to keep solvent tubing at the bottom of the reservoir. They are usually available in various frit porosities. For analytical HPLC applications, a 2 µm frit is the best choice, while a larger-porosity frit, such as 10 µm, should be selected for flow rates exceeding 10mL/min to avoid starving the HPLC pump with a too restrictive flow path.