AN ANALYTICAL XRAY SERVICES LABORATORY
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Posted by: In: Uncategorized 29 Jul 2020 0 comments

I was recently approached by a friend with a question about generic pharmaceutical products and their relative efficacy. It turns out she’d received a refill on a prescription for duloxetine HCL, a generic version of Eli Lilly’s Cymbalta product. I assured her that based on my years of experience working with all type of pharmaceutical manufacturers from stage one development to giant corporations like Pfizer that an incredible amount of effort goes into making sure that any generic drug performs equivalent to the original. However, I offered to run some XRD tests on the previous and new medication to ease her mind.

The results were a bit startling. The previous product showed clearly present and well-crystallized duloxetine HCL along with lactose monohydrate while the new capsule had no phases I could identify other than sucrose. None of the crystalline polymorphs of duloxetine HCL, nor any evidence of the amorphous scatter pattern one would expect were visible to me.

After verifying that the prescription had not been changed to a placebo (my first thought), I set about analyzing more samples. The initial capsules were both 60mg dosages, but the same prescription included a second, 30mg dosage. This was filled at the same time, at the same pharmacy, and from the same manufacturer as the 60mg capsule in question. It also showed clearly present duloxetine HCL. A replacement prescription was ordered and filled from a different pharmacy and by a third manufacturer. It also showed the clear presence of the API in the most common crystalline polymorph.

The D2 Phaser 6-position autosampler uses a completely different sample holder that their other systems. We’ve just completed our first production run of these blanks so they’ll be ready for custom orders. Contact KSA for more information.

XRD patterns are complicated by a variety of undesirable effects. Some of which are easy to deal with, others are unavoidable. One of the issues we see often is scattering and diffraction effects that are actually being caused by the sample holder itself. These effects can usually be modeled out, but simply knowing which artifacts are being generated from scatter off the sample holder vs amorphous content or phases present in the sample itself can make the difference between an easy analysis and a grinding, iterative march toward a final result. One of the most common effect we see is scatter from plastic sample holders. Most of the sample holders we produce are either Aluminum or PMMA plastic, but either way, one of the easiest ways to avoid undesirable scatter is to simply enlarge the sample well. We’ve been doing this for decades on the standard, non-rotating sample holders by cutting a large, rectangular well rather than the standard, 25mm circular well.

This week we did a little experiment to see just how much larger our sample well needed to be to eliminate the common PMMA hump at ~13 degrees 2Theta (Cu energy). It turns out that an increase of only 5mm in diameter made a huge difference in the total scatter even with very “wide-open” optics. See the scan images below for a real-world picture of the difference we saw. This may not seem like a significant problem until you’re looking for phases with D-spacings down in that region near the hump. Analysis of clay minerals can become particularly complicated. This is a great example of why we love talking to clients and XRD users around the world.

MDI Jade has been our goto analysis suite for powder XRD data for decades now. Powerful, versatile, and well supported, it’s earned a following second to none in the industry. What began as a simple suite of MS-DOS-based programs in the early 1990s has blossomed into a full-featured toolset for just about any kind of powder XRD analysis one could need. As computer hardware and software platforms evolved, Jade grew right alongside them with more powerful features, faster processing, and even greater flexibility.

Several years ago it became apparent that the core programming of Jade was going to become a limiting factor in its development. Enter Jade 2010.  Built from scratch on next-generation architecture, Jade 2010 freed up the developers at MDI to implement many of the changes they’d been wanting to add for several years. The result was a beautiful new interface with streamlined and reorganized menus that greatly improved the user experience. The new structure allowed for much more integration between features that had once been modular, making them easier to use as well as more powerful. The original Jade suite (now on version 9.8) became Jade Classic and it became clear that there was a sunset coming for the venerable program. The only complaint we ever received about Jade 2010 was that it was only available as an annually-licensed product. Each year the users would need to renew their subscription to continue using the software. This gave me pause just as it did many of our clients, but the rapid pace of development almost necessitated this as new changes and updates were taking place monthly rather than yearly as they had in the past.

Fast forward a few years and we’ve had another big change. Jade Classic (9.8) has been discontinued and Jade 2010 has become Jade Pro. It’s still all-inclusive with all the advanced capabilities available on every license. It’s also still an annually licensed program. Development will continue free from the limitations of the old core programming and the distraction of maintaining two completely separate products.

This alone wouldn’t be such big news, but there is a new option that we’ve been waiting for years to see. Jade “Standard”.  We now have four additional products available to users with more limited needs and budgets.

Jade Standard level 1 includes all the basic pattern analysis and manipulation tools that users would need for many of the more common projects as well as some of the more advanced features that were only offered on the premium Jade+ (plus) program before.

Jade Standard level 2 includes all the level 1 functionality, plus Search/Match (2a) or Whole Pattern Fitting/Rietveld (2b).

Jade Standard level 3 includes both Search/Match and Whole Pattern Fitting.

All Jade Standard products are perpetually licensed (One-time purchase, lifetime license).

Several of the ancillary tools offered by MDI are still available as always including Ruby, ClaySim, and RIQAS.

We’ve been waiting a very long time to be able to make this announcement and I must say that the way this has been implemented couldn’t be better for ourselves or our clients.

Please contact KS Analytical Systems for more information and upgrade pricing.

We often receive requests for small powder wells to be ground into our zero-background sample holder plates. I usually try to talk the requestor out of this as it has limited usefulness for most applications, but there are some reasons one might benefit from this type of holder. It’s for these special cases that we’ve always offered custom ground wells in our ZBH plates and we continually improve our process to give our clients exactly what they want and need to get their work done.

There are three reasons I try to avoid this.

  1. It adds cost. The very small grinding tools required for this cut very slowly. This is partially to avoid building up heat in the plate which will shatter if it goes too far. In the foolishness of my youth I once tried to score large wafers with a CO2 laser. After two passes it would explode leaving about 50% waste material, but it got the job done. Heat is your enemy when it comes to very hard materials like this. We also don’t use pre-ground plates. Each one is machined from a flat plate after it’s been mounted in the sample holder to ensure perfect alignment with the plane of diffraction while also giving us the freedom to cut any shape/depth we could want. I.e. if one wanted a square or oval shaped pocket, we could machine that. All this flexibility adds up to additional work/time which adds to the cost of each holder.
  2. It’s often unnecessary. If you have enough material to fill most wells, it probably won’t be transparent to x-rays anyway. I find that many users of sample holders with wells could get by without them by simply using a smaller well in a standard sample holder. The additional scatter from PMMA plastic may or may not be a problem, but if the user can live with it, it’s a huge cost saver.
  3. As soon as we break the surface, we’re no longer dealing with a monocrystalline material. I’ve never seen any practical evidence that this causes a problem, but it’s always concerned me that grinding these plates essentially creates a polycrystalline material at the surface of the well. I would love to hear from anyone who’s ever seen a weak Si pattern superimposed on their data.

One alternative I often recommend is recessing the entire plate by some number of microns to accommodate different particle sizes if that’s a concern. I believe that many XRD users are asking for sample wells in their ZBH simply to avoid the displacement error inherent in mounting their powder on top of a plate which has already been fixed at the plane of diffraction. Recessing the plate allows us to retain the polished surface of the ZBH and allows us to mount it with at least the same degree of precision that a well would provide. Precision mounting adds about as the same cost as grinding, but it definitely has benefits. To my knowledge, KSA is the only company offering this type of mounting.

So that was an awful lot of reasons to avoid this, but there is one very big benefit of using a ZBH with a ground well. This allows you to run very small volumes of sample material while maintaining a very consistent irradiated area. Imagine the same volume of powder spread across a flat plate. Each time this is done, a slightly (if not significantly) different surface area of the plate is likely to be presented. The end result of this will be variations in intensity and perhaps preferred-orientation. Particle statistics change with varying numbers of crystallites in the plane of diffraction as well. This is all complicated by the changes in the irradiated area throughout a normal scan with divergent-beam optics.

The well pictured here is 12mm in diameter and 0.2mm in depth and a good example of the kind of custom work that is most common for us.

Posted by: In: Uncategorized 28 Nov 2018 0 comments

I often explain scientific exploration as the search for minimal uncertainty. We perform an experiment more than once to verify our results, but in actuality, we’re only reducing the uncertainty by some degree. There’s almost always some possible explanation that would negate our conclusions, but in most cases, we live with this relatively small degree of uncertainty. We’ve worked on projects which required greater degrees of scrutiny than average, but we recently took on a project unlike any we’ve worked on before.

A lawyer contacted us late on a Thursday even looking for very fast turnaround AND a very high degree of certainty in the results. This really plays to our strengths so we took on the project. It was the 11th hour and quite urgent because another lab had tried and failed for reasons that would become obvious as we dove into this work. The goal was simple enough. We needed to verify the presence of a particular phase. As it turns out, this was a key piece of evidence to be used in ongoing patent litigation between two companies. The phase in question was very low in concentration and the key peaks were obscured by others close by. In the end, we worked four days straight through the weekend to get a report out in time to be admitted as evidence. At one point we had three diffractometers collecting data simultaneously with one being heavily modified for maximum angular resolution.

We’d verified the presence of the particular phase and had double and triple checked the data. Our level of certainty was well beyond the norm. However, unlike any of our previous work, we found that we were no longer working against “reasonable” doubt, but rather, endless scrutiny. Any argument, no matter how ridiculous, had to be countered over the weeks preceding the court hearing. No one likes to hear their work criticized, but I must admit, we’ve never been so certain about any results as we were after a team of experts tried their best to tear our conclusions apart.

The case went to trial and in the end, the expert testimony we provided proved beyond any reasonable (and even extremely prejudicial) doubt that the phase in question was present. I’m not sure if this has left me with more or less faith in how our justice system works, but it definitely opened up an area of the laboratory business we had never explored.

 

XRD sample prep is like a box of chocolates. You never know what you’re going to get… So many materials are fluffy or sticky that even after fine grinding, it’s common to have some clumps that just don’t want to break up. This became a problem for one of our clients using our side-loading tool so they added a piece of mesh to the mouth of the funnel. Their next order included a request for some type of removable solution for this so we mounted some coarse mesh in an acrylic frame that sits nicely on top of the funnel and makes it very easy to sift through sample material as it’s being loaded. We love these so they’ll be an option on all future orders!

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Clay minerology is a fascinating subset of the common powder XRD applications we work with. It seems like every lab has their own unique way of handling the various challenges presented by clays and hence the need for myriad solutions. Most recently we worked with a lab which processes large volumes of clay samples in their various Bruker XRD system and they needed a sample holder that would accommodate their 26 x 26mm glass slides on which their clays are mounted. The solution was a custom holder with a square recess for the plate which is simple enough, but in cases like this, one must take into account the real-world challenges of machining as well as usage. The edges and corners of the glass slides are the least precise part of the plate so the holder has a “moat” around the perimeter to eliminate binding or shifting due to those issues. The center is also relieved as this area does almost nothing to improve precision of the mount, but will cause dramatic displacement errors if any debris gets between the holder and plate in that area.

These were a little time-consuming to make, but the end result worked beautifully. The client was very happy and we’re happy to have another design to offer to other labs with similar needs.

 

Our lab sees a very wide variety of sample types and they are almost always 90% unknown materials. So while we’ve always offered elemental analysis by WDXRF, sample preparation has always been done by the least destructive method. That means powders and solids get crushed, ground, and pressed into pellets and liquids either get run as they are under a He flush environment or dried and filtered for particulate matter. These techniques work well for qualitative analysis and can also be extremely effective for quantitative work assuming proper preparation and a good calibration curve.

However, we’ve been working on a comprehensive calibration curve for geological materials recently and the simple fact is that the very nature of these materials makes them very difficult to measure in their natural state. The fact that the various elements may be combined in any number of different minerals as oxidized, reduced, or metallic phases makes analysis by XRF, even WDXRF very difficult. The solution to these problems is Li-Borate fusion.

I’ve resisted getting into fusion for a number of reasons, not the least of which is the substantial cost of entry if you’re going to be running much volume at all. It’s not hard to spend $70-90k on the tools for an automated preparation setup. After researching all the major manufacturers we came out with a few front-runners that are worthy of note. These are only the models we looked at so please don’t consider omission from this list as a negative comment on any company or model.

Katanax was our first on our list as a few of our clients are running these systems. The electric oven style heating is very convenient and the fully-enclosed design was also quite attractive. They also have three different models with single, up to 3, and up to 6 positions for simultaneous fusion. The touch-screen interface is large, well-laid out and easy to work with. While all this sounds great, the best part about Katanax in my estimation is their support. Talking with their applications experts was a great experience and I could tell this was not just a job, but something they truly enjoyed. I recommend Katanax for anyone new to fusion who might need some help. The only things we didn’t like about the Katanax models was the “swirling” motion style which is a simple tilt back and forth and the electric oven heating. With most crucibles, the swirling motion won’t have any effect on results, but I was partial to the 360-degree rotation style. As for the electric oven, this works great for labs with higher volumes, but we aren’t expecting large volumes of samples any time soon and the idea of heating the entire oven for just a couple samples would have ended up being time to consuming. If you know your volumes will always be low, the single-stage K1 Prime.

 

Another model recommended by several of our clients was the Phoenix sold by Premier Lab Supply. Premier deals with several different models of fusion systems with gas and electric options, but we were focused on gas by this time. The Phoenix had a few unique features like O2 injection and a mechanism by which a non-wetting agent tablet could be introduced very late in the fusion step. This is necessary with some non-wetting agents and a very nice feature to have. The Phoenix is also expandable and we liked the fact that one can specify which positions are to be used for a particular fusion so all the burners don’t need to run if we’re just running a single sample. One of our clients at USGS has been running the original Phoenix models for many, many years and I’ve heard nothing but glowing praise for it. Again, reliability and the availability of support are extremely important to us and I believe Premier would have been a great choice. The age of the Phoenix 1 was a small issue and the interface is a little dated, but it really came down to physical size. This is a big machine and would have taken up a fair bit of our sample prep area. I’m quite confident that any lab would be well served by one of these.

 

No discussion about Li-Borate fusion would be complete without a nod to Claisse. They have options for just about everyone, but we were looking at the Claisse M4. The M4 is an older model, but offers some very nice features. Their swirling mechanism is easily my favorite as the crucible rotates continuously. The machine is also remarkably space efficient for being a 3-position system. The interface was the weak link for us compared to the newer models with touch-screens. Another minor issue that I’d never considered till we actually started running a fluxer in-house was that it’s very convenient to fill the crucibles from weighing boats while they’re installed in the machine. This would be difficult to impossible on the M4. I would expect a very high level of experience and support from Claisse, but didn’t actually get that far in our conversations. I should mention that we’ve seen several of the Claisse Ox machines out and about. They seem to be a great solution for high throughput labs.

 

 

Last, but certainly not least, we have the Nieka G4 series (sold by Chemplex in the US and pictured at the top of this article). This is the unit we eventually settled on though I had never heard of it until recently. It was simply the right machine for us with a 4-position configuration, bright and relatively easy to use touch-screen and an open design. We actually ended up with a propane version which was another last-minute choice that we were very happy with. This allows for very easy installation, portability (hard to believe that’s a feature, but in our evolving lab, it’s great to know that we can move it anywhere we want with ease), and a higher energy density fuel than natural gas. The swirling motion on the G4 is a circular motion which works very well for mixing up hard-to-dissolve powders. The integrated software offers a very high degree of control which may or may not surpass the others shown here, but we really appreciated this while we refining out fusion recipe. Extending the time for a certain step, adding steps, etc were all very easy.  No PC or other interface was needed or even wanted. The open design makes working with the crucibles and loading flux/powder a breeze. If there is a caveat for the G4, it’s that while Chemplex has never failed to get us an answer to any of our applications questions, this definitely seems to be a new branch for them. I assume it will take some time to build up an in-house knowledge base, but we didn’t need too much hand-holding to get started. For users with more consistent materials, I would recommend you take them up on their offer to develop a fusion method for you. This can be done entirely remotely and would probably have been a great option for us if we didn’t have such a large variety of materials coming through.

We’re probably about 100 fusions in and the machine has not missed a beat or given us the least bit of trouble. The amount of control available is likely a large part of this. We were able to fine-tune the oxidation, fusion, pouring, and cooling phases with multiple steps for each which has allowed us to create a recipe which covers a wide range of geological materials from shales to silicate rocks.

 

Update 23-MAY-2018:

We actually had our first interaction with support for our G4. One of our crucibles cracked during the heating stage. I’m not sure what caused this and neither was Chemplex, but it appears to have been some type of stress as it was right on top of a bulge. Getting a replacement was effortless and fast though. Having good, local support is another factor in this decision that was very important to us and I’m happy to say that our first issue was taken care of very quickly. Thanks Chemplex!

You can never have enough sample holders no matter what machine you’re running. We’ve certainly found this to be true at Texray so we always try to keep a large number of them on-hand. KS Analytical Systems has always made one-off and custom sample holders for the Bruker instruments, but we’re now offering the standard PMMA powder holders as well at significant cost savings over the OEM version. The standard holder (25mm x 1mm deep well) is priced at $55 with bulk discounts starting at 20 holders.

Custom well depths, diameters, grooved floors, side-loading and zero-background versions are available.

Our PMMA holders are compatible with Bruker D8 Focus – D8 Advance (single, FlipStick autosampler, 90-position autosampler), D4 Endeavor and D2 Phaser (single only) systems. D500 and D5000 instruments can also use these holders.

We’ve brought the complete manufacturing process in-house to give us the freedom to make the custom designs our customer have always asked for. This includes custom laser etching. Company logos are a common request, but we’ve also started serializing sample holders on request. At Texray, we even etch them with barcodes for tracking samples through the data collection process.

The pictures below show a custom funnel tool for filling side-loading sample holders. The tool is machined from billet aluminum with an acrylic window on the funnel to make it easier to gauge fill level. The funnel itself is polished and the viewing plate which allows the users to see when the sample well is full is made of sapphire crystal for maximum scratch resistance.