CSI and the purge-and-trap

>> July 3, 2010

Recently, an article at "The Economist" described what is called CSI effect: The fact that this TV Show is raising the expectations of Jury members about what forensics sciences can or can not do. Maybe, the bad side of science popularization. This is simple because in TV Show everything is wonderful, and sometimes almost magical.
No long sample preparations, analysis always works and answers are just some clicks away.
We all know that in real world things are little different.

The video below is good exemple of what chromatography can do in forensics, except for the almost instantaneously results. (Believe me, last time I did something similar, the run tooks 2 hours.)

By the way, The use of Chalk as adsorbent go back to Tswet times and still have some studies today, here and here for instance.


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Coming back with some news

>> June 27, 2010

After some (very long) Vacations I come back with some news:

First, the 5th Edition of "Practical High-Performance Liquid Chromatography" (Wiley) From Veronika Meyer is out there.

Second, V. Meyer  also has a recent (and very interesting) publication:
The 1000 bar and 24 hour limits of one-dimensional HPLC - graphical representations

In this paper, many possibilities of actual technology are discussed and/or just plotted.
Although  a lot of mathematics, is not complicated to understant and most terms and logics are known by any chromatographer. Worth a reading.

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Best explanation of what chromatography is. IMHO.

>> April 3, 2010

When I have to explain how chromatography works to someone, I use a “Theoretical Model” I stole copied from Ralph Calvert of http://www.itsjustabox.com/
The theory (which I modified) starts with:

Retention
Basically, imagine a corridor in a shopping mall with many shops, full of people, and all of them are going to the restaurant in the back. Then a large group of friends enter, and agree to meet at the same restaurant for lunch.
Now consider this:

-When they enter the corridor, this is the injection.
-The corridor is the chromatographic column.
-In this model, the group of friends are the analytes, the compounds that need to be separated. Each friend has different caracteristics, different tastes for window shopping.
-These shops are the active sites where the retention effects (interactions) take place.
-The people that do not belong to the group of friends or family acts like mobile-phase. They not only carry (push) the friends group forward but also interact with shops displacing whoever is looking at the shop window.
-The restaurant is the detector.

With this in mind. imagine now that after the group enters the corridor, some of them, which have more "affinity" for the shops, stay longers looking the windows or buying stuff. Those who do not have any interest in this stuff, arrive faster in the restaurant.

Some people who don't have any interest at all, arrive without even  looking at the windows. They are the Dead Time Marker.

The group, starts to walk and some friends start to look and spent more time at certain shops, and they then divide into the clothes and book groups. The clothes group takes longer at the shops and is the last to reach the back. The books group arrives before them, but much later than the Dead Time Marker group.
This is the separation.

The solvophobic Theory
Although not accepted today, the solvophobic theory can also be explained in the “shopping model”.
It was created long ago by Csaba Horváth one of fathers of modern HPLC and explains the mechanisms of retention on reversed-phase liquid chromatography, where the mobile-phase is polar and the stationary phase is non-polar.
In the Solvophobic model, the Stationary Phase plays a less important role in separation. It was believed that analytes tend to adsorb in the stationary phase due to their incapacity to be solvated or form a cavity in the strong polar solvent
Now re-thinking this in our shopping mall: our group of friends just don't feel confortable in the crowd that try to push them forward. So they rest at the shop windows where they are less stressed, pushed or whatever.

 Peak Fronting

Just imagine the clothes group being attracted by a huge shop with special prices. Almost all the friends got in front of the shop but there is no space enough for all of them. Due to the traffic of people in corridors, the people that are in the back row can’t stand there too long, so the moving crowd going to the restaurants pushes the girls to the next shop with clothes. Basically there’s no enough space for all of them to express their attraction for the itens or check the prices.
I'm just talking about an overloaded situation, in which chromatography generates the famous Shark shaped peak.


Peak Tailing

Peak tailing is caused by a secondary interaction of analyte with something in the stationary phase, the most traditional situation is with an amine compound interaction with a free silanol in the Stationary Phase.
Imagine that our “model” group of  friends is interested in shopping for clothes, but  they also see some shoes shops on the way, so the group goes from one clothes store to another, but when they cross the shoes store some people are delayed and the "pack" of people on corridor start to be more spread out. 

Ion Pair Retention
There are two models for ion pair chromatography. First say that the analyte compound , in this case the people, combines by means of electrostatic forces to a counter ion and both are retained in the  hydrophobic stationary phase. Second model says that the counter ion is retained on the surface of hydrophobic stationary phase and then it retains the analytes, like in a dynamic ion-exchange chromatography.
Both theories can be described here. In the first, let's imagine the ion pair as a real couple that is formed when the group is in the crowd. The couple then moves to the shops looking for something they have in common, like sports. In the second situation, the group passes and they meet with another group standing in front one of the shops, after a fast chat, they start to walk again and meet with another group in front of another shop.

Scientifically speaking, it's not a perfect description. But at least, it's funny.

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Upgrades, Retrofits and Add-ins: Seeing Oxygen

>> March 15, 2010

When I was in College one of main complaints about graduate students was that they wasn't interested in self-employment or start their own bussiness. No one wanted to leave the bench and become a bussinessman.
This is much more common in other countries, I mean, someone start a bussiness witht the know-how he got in college. It was in this way with Craig Hamilton from HA Scientific and it's very similar with Dr. Paul L. Patterson from  http://www.det-gc.com/
He works with something I never saw any company dealing. Replacement ceramic beads for NPD that with combination with certain instrumental conditions can expand the analyte selectivity or modify it.
This is not a OEM product, they have a new technology that can be added to an existing GC detector.
The most interesting for me is the selective detection of oxygenates, you can see a chromatogram at left.

You also can find more information about the standard Nitrogen Phosphorus Detector on thins book chapter on Google books:



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Show your friends what you do

>> March 3, 2010

I got 2 serious questions on this video:
1- Did they retrofit that start button on top on this Shimadzu?
2- Is the analyst an actress or she really does this job in real life? I don't know about you, but here I don't see many cute chromatographers girls around.


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Honouring the "Color Writer" name: Cyanotype prints

>> February 21, 2010

Not really involved in chromatography but in chemistry.
Cyanotype is a 170 years old technique based in reduction o Iron (III) by ultraviolet light forming the Prussian blue.
The most interesting is the X-Ray look.

In the image you can see:
Hollow Cathode Lamp (for AAS).
Vials, microcentrifuge tubes.
0,45 µm Filters.
A HPLC plunger (piston).
A piece of Glass Packed GC column.

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Konrad Grob - The Value of Education

>> February 6, 2010

Originally published on Restek website for Restek Advantage, 1999, Volume 2.
Reproduced with author’s authorization

by Dr. Konrad Grob, Kantonales Laboratory, Zurich


In my last Korner, I concluded that only an education and qualification system could prevent chromatography from further decline. Instead of devoting time and effort to force better chromatography through quality management schemes, validation, accreditation, and bureaucratic piles of paper, I suggested that institutions invest in improving the quality of their employees. In this way, both the employees and the employers share the responsibility for improvement. Employers should realize that knowing how to manage a crimper for closing autosampler vials (despite what some instrument vendors may claim) is not "all" it takes to make a gas chromatography (GC) laboratory successful. At the same time, if analysts want to be considered valuable assets, then they should be ready to take an examination that affirms their education and training. How much education is necessary?

I received an overwhelming response to my article. Almost all of which confirmed my conclusion. For the sake of argument, though, I would have liked to hand over the microphone to somebody who disagrees. However, without refuting my point, I will take a moment to gain a perspective on the questions of 1) How simple is GC really? and 2) How much education is necessary? When observed from a safe distance, the work of a GC analyst appears simple. A gas chromatographer performing routine analyses should be able to help troubleshoot when results are not appropriate. The analyst should, in addition, be able to "rapidly" analyze x in sample y, and know how to select the right column, the injection technique, and all the many parameters finally determining whether the analysis will be successful. If capable of developing methods, the analyst needs to overview the possibilities and the problems to be expected; the clever choosing of strategies, tools, and conditions that may save trouble over years and reduce the time needed per sample by a factor of more than two.

No doubt analysts who are able to answer common GC questions achieve more reliable results because they can find the pitfalls. While other people waste several days because an analysis does not turn out adequately, these analysts find tests that can rapidly localize the problem. They know beforehand that aqueous samples are more difficult to analyze and should be injected in small volumes.

In industrial countries, every working day costs around $1,000. Eliminating three days of expense per month by improved troubleshooting saves $3,000 for that month. You easily can save several days per month by using better methods or improving performance of given methods. A knowledgeable gas chromatographer can prevent visits by the service engineer and avoid other delays disturbing production or delivery. If half of the profit generated by more competent work goes to shareholders, the analyst's salary should increase by $3,000 at least.

Photo by Robert Doisneau

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Strange places to find a Chromatographer, Part: IV Software Company

>> February 1, 2010

No, he doesn't program games, he does chromatography software there.

Mr. Craig Hamilton see the chromatography from Inside, not inside the column but inside acquisition software and hardware. After a Master Degree in Analytical Chemistry with emphasis on chemometrics, Craig became a businessman and now operates a company with a 3 language acquisition package (soon, four with portuguese!! yes, that's my job!), with support to Ethernet connection, LIMS and in future with SQL and Oracle functions.

Craig will tell us about his experience with the computer world, and in the business world also. Thanks Craig!

By Craig Hamilton, H&A Scientific:

If you are lucky, you are healthy and happy and life lasts a long time. If you are luckier, you embrace the rare opportunities for change that can better your life. The luckiest of us work very hard to make those changes become reality!

Thus, it seems very natural to find a chromatographer in a Software Company. Of course, it is year 2010 now, so one must look back to the early 1990’s to understand the “why.” The “why” is that as the world was changing from the “paper strip-chart recorder” world to the “computerized” world, it was only natural that a chromatographer who understood computers would “cross the line” from “analytical chemistry” to “software developer.”

So for a chromatographer to make the transition from “the lab” to “the keyboard,” there must be a “need.” It’s like the old saying, “Necessity is the Mother of Invention.” The need was there for computerized chromatography data stations, and there were chromatography software programs available in the early 1990’s, but the prices were out of reach for most of us in university research laboratories. Any chromatographer who has ever been forced to analyze a variety of different types of samples using only a pencil and ruler to measure “peak heights” knows this need.

We all have read stories about how chromatographers used to “cut and weigh” peaks on strip chart recorders prior to the computerization of chromatography, but in reality, it’s not really a viable option in “the real world.”

So the need was there, and the funds were not, so let’s push forward to fulfill the need!

Borland Pascal was generally the programming language of choice for scientists in the 1980’s and early 1990’s. Borland had made a commitment to educational institutions, and Pascal was the obvious language of choice for scientists, as Pascal was originally developed to be a teaching programming language, and did not have all the complexities and idiosyncrasies of Fortran and C. Alternatively, the Basic programming language was not even considered, due to its lack of forced structured functionality at the time.

So for a chromatographer to be able to “program” such a chromatography program, they must have been introduced to “computer programming.” That is why higher education is so important to all of us. By obtaining a Master’s Degree in Analytical Chemistry with an emphasis on Chemometrics, one must really learn the art of computer programming, as Chemometrics is by definition the interface between chemistry and mathematics. Even in the late 1980’s and early 1990’s, in order to extract useful information from both fields of study, computerization was essential. Thus, programming skills were essential to complete the requirements for this field of study.

For example, one Chemometrics technique learned was “Self Modeling Curve Resolution (SMCR).” SMCR is the name given to those algorithms that make only general assumptions about multivariate data in order to resolve the contribution of each chemical species to the total overlapped curve. The specific technique used was Evolving Factor Analysis (EFA), allows one to extract the “unique” spectra of unresolved spectral mixtures (within reason). Chemistry and Math, tied together by the new computer power at hand!

It’s simply impressive to see unresolved spectra of mixtures be resolved by this powerful technique!

But prior to obtaining a Master’s Degree in Analytical Chemistry, the original question remains, how does a chromatographer “really” get involved in learning a programming language? It’s really simple, just buy a used IBM computer with two floppy drives in the early 1980’s, set it up in front of one’s television at home, grab some popcorn and a cold beer, and learn how to use it. Eventually one can take a class at the local community college in Pascal, and realize halfway through the course that computer programming is a logical process, just like chromatography and science in general, and then get so bored with the class you eventually drop out! No problem, by then one is “hooked,” truly enjoys it, starts writing programs totally on their own, and there is no turning back!

Returning to the task at hand after graduate school, first and foremost, for a chromatography program, the raw chromatographic data must be accurately recorded. This requires one to understand the analog-to-digital conversion process. All the software is built around this process, as it is the most critical. Secondly, software functions must then be written to accurately calculate peak areas and heights, as these are also critical and fundamental to a chromatography program. Thirdly, the source code to calculate concentrations of the “unknown” samples must be written so that a final report can be generated.

These three phases are all critical, and each one relies on the proceeding one to yield the final answer the chromatographer is seeking!

So the realization that after graduating with a Master’s degree and subsequent employment in a specialized research role at the university, it becomes apparent that this specialized employment role can be safely played until retirement. But if one wishes to change for the better and make contributions in multiple future roles, and make any of these contributions worthwhile outside of their assigned role, then one must move forward.

Thus, while still employed full-time at the university, it became apparent the preliminary programming work toward creation of a basic chromatography software program could be completed at home after working a full eight hours at the university.

Basically, the thought process can be summed up with the old saying, “Behold the turtle, he only makes progress when he sticks his neck out.”

The question remains, how does one “practically” make the transition from a stable university position to the extremely challenging position of entrepreneur? There is no easy answer. I would guess that the most important attributes required are a willingness to work very hard (actually this won’t do it, one much actually be prepared to work very, very, very hard…the chance to be a true entrepreneur cannot even be considered unless one is ready to “give it all they have”), strive to be an optimist when everything is falling down around you, embrace the chance to change for the better, and through sheer determination, just make it work. When failure is not an option, the only path is to plan and push for success. It’s that simple.

So one moves forward after making the full commitment to be a true entrepreneur, with no safety net, according to the rules outlined above. It’s a thousand times more challenging than was planned. Sometimes one looks back, but there is really no time to dwell on the past, as good decisions have been made, and the only choice is to move forward.

Another old saying is “To be a good biologist, one must first be a good chemist.” The parallel is “To be a good Chromatography Software Developer, one must first be a good Chromatographer!” Of course, in today’s world it is essential to be surrounded by and assisted by Computer Scientists, Project Managers, Validation Engineers, and a Quality Assurance Program.

The chromatography software was translated from DOS Pascal to Delphi, Borland’s 16-bit Windows implementation of Pascal, in the mid-1990’s. It was later translated to C++ in the early 2000’s to take advantage of the 32-bit world and various software libraries that were available in C++ and not Pascal, although the current Borland Delphi Pascal compiler is still a wonderful product.

Eventually, we will write a database backend for our chromatography program, with Microsoft’s SQL Server being the database of choice, and of course we will also make an Oracle database backend. This will fulfill the requirements of very large laboratories with many simultaneous users.

However, “at the end of the day,” the software must work for the chromatographer! Thus, it still makes sense for the software developer to be “one and the same…”

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Konrad Grob - Do We Need a Chromatography School?

>> January 24, 2010

Originally published on Restek website for Restek Advantage, 1998, Volume 3.
Reproduced with author’s authorization

by Dr. Konrad Grob, Kantonales Laboratory, Zurich
Sometimes things need to be said in a pointed way. The following is one of those things. If even less than 50% is applicable, then it is enough to sound an alarm.

The Slow Sinking of Chromatography

I grew up in the good old times when the world believed in chromatographers. We were proud of what we did, could work in our own way, but were also responsible for our results -- we were our own maestros, playing our chromatographs with the best of melodies. But, then misery befell us. It was suspected our results were faked. Bureaucratic methods like Good Laboratory Practices (GLP) were invented and, ever since, many of us must document every move we make. We wanted to work in the lab, not do office jobs on an uncomfortable lab chair, didn't we?

Confidence in our results was lost almost completely. This has its origin in embarrassingly poor results delivered by some labs, but also in the difficulty of the public to understand that our results may have a substantial margin. They may think that if an instrument is expensive, the results must be absolutely accurate. At court, results are no longer questioned on their accuracy, but on the paperwork behind them: when was the balance checked last, and is there a certificate proving that the hexane was not water. Shouldn't we feel offended by such general distrust? As a consequence, much of our work has become regulated in minute detail, with many ideas having a penetrating odor of stacks of paperwork and meeting rooms. Many methods grew to be more than 10 pages, half of which are taken up with titles and decimal numbering. They specify standard compounds in every detail, as well as simple manipulations like how to rinse a round flask. However, they all too often do not even mention the tasks that cause real problems, such as the details on how to perform injection techniques. Have we lost all of our competence or are some totally unskilled lab workers dictating our lab?

Lab Work Degrades

In many labs, work has become dull. It has degraded to the execution of recipes -- as mundane as making hamburgers, only having more frustrations and a lower success rate. Your results are accepted only if you have a validated method and a certified standard. Many methods could be greatly improved, saving large amounts of time and money, but changes presuppose such a large amount of rework that most people just keep quiet. It is performing analyses in chains. Many of the best chromatographers are no longer finding enjoyment in such work.

Commonly, lab supervisors are no longer in the lab. They are chemists who learned hardly more about chromatography than interpreting a van Deemter curve. For them, going into the lab might mean learning the basics from the supervised -- it is easier to design Excel spreadsheets and manage quality from a safe distance. Analytical refugees because of a lack of chromatography education?

It is sad to see such an exciting field declining. GC would not be the first chromatographic technique to degrade. Thin layer chromatography (TLC) is an excellent method for many purposes, much faster and cheaper than some other methods. However, where could I learn the art of TLC today?

Quality Management, a Makeshift Solution

Much of quality management (QM) resembles a desperate support structure used to stop the decay of analytical chemistry; a sophisticated system to protect against a lack of competence. However, in reality, QM might even accelerate the decay as it chases away the good analysts by way of boredom and frustration. Many newcomers have no proper education and will hardly develop a passion for the work they encounter, and only look at peaks when asked to do so in bold letters. Many laboratories have lost their competence to create or modify methods. In the end, the pessimists are right: merely the most rigid and painstaking descriptions prevent people from doing the incredible things that many technical support services hear about every day. Analytical chemistry risks collapse, despite -- or maybe because of -- the rapidly growing QM systems.

A Need for Better Education

Is there anything we can do to stop this decline? The key problem concerns competence of the analysts. Chromatography is demanding and requires professionally trained people. Analysts must be masters of their field, motivated to do their work well and react promptly if something peculiar is observed. They should feel responsible for their results, but also be recognized for performing a difficult job. Supervisors must be knowledgeable leaders in chromatography, guide with ideas and suggestions, understand problems, as well as pick up and support the good ideas of their people. Emphasis must be moved from paper-leaden QM systems towards ensuring the competence of the analysts.

Many of the modern technologies suffer from lacking education. In new fields, the originators are the natural teachers, informally passing on their knowledge. When they leave, classical education should take over. However, universities are unable to offer this service for all the emerging fields and there is not enough room for chromatography in the teaching of general chemistry. Hence, new models of education are needed. We might also need an internationally recognized qualification system, so that well-trained chromatographers are recognzied as specialists in their field. The problem is serious and a great challenge for all who are willing to keep alive a field in which more than 500,000 persons are working.

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Strange places to find a chromatographer, Part III: Climbing the Everest

>> January 17, 2010

No, she is not measuring the level of Ozone there with a portable GC, she likes to climb.


Frau Meyer is an author of a well known chromatography book: Practical High-Performance Liquid Chromatograph (which I used in university by the way), several papers dealing with uncertainty, acetonitrile detoxication and more. She is also a research from EMPA. None of this impressed me more than know that she got a valve on heart and had climbed all the Seven Summits, The highest mountains in each continent!
She kindly answered some questions. Take a look:











How did you put this goal in your life, it was planned? I mean the 7 peaks?
No, it was not planned. The idea of Seven Summits was first presented by Dick Bass, end of the Eighties. I liked the idea but I was convinced that most of these mountains are out of my reach. So far I had only climbed in the Alps, however, a lot! But then I grasped every occasion when I saw that I could participate in an expedition to one of the Seven Summits. By the end of 2001 I had climbed six of them (and Denali and Vinson were not easy), so I asked a Swiss expedition leader, Mr. Kari Kobler, if he would accept me as an expedition member to Everest. He did, but it took me five attempts (2002, 2003, 2005, 2006, 2007) to finally reach the top on May 16, 2007.

Do you think in job when you are in the mountains?
Most of the time I don't. But sometimes I get a good idea when I am in Nature (also when climbing a mountain in Switzerland). In addition, when you go on expedition to Everest or another really high peak you must be aware that there will be resting days. Sometimes you need to wait for a week or longer due to the weather. Therefore I always took a little bit of work when going to a long expedition. E.g., once I updated the paragraph about sample injectors for my book "Practical HPLC" (in Everest basecamp) and once I worked on a paper about the uncertainty of weighing operations.

Beyond books is there any publication you could stress like, very important? Or had more impact?
In fact, I cannot judge the impact my HPLC books have, although I think that really many people use and like them. Besides the books, there are (at least) two papers of mine which generated some impact:
Richard Däppen, Hans Arm, Veronika R. Meyer
Applications and limitations of commercially available chiral stationary phases for high-performance liquid chromatography. J. Chromatogr. 373 (1986) 1-20
This paper got 114 citations until now.
Veronika R. Meyer
High-performance liquid chromatographic theory for the practitioner
This was one of my first papers. In these years it was usual to send a postcard to the author if you were interested in a paper and wanted a reprint. I got over 600 of these cards! It was cited 33 times until now.
How do you see education in chromatography today? What are the ways to achieve proficiency in your opinion?
I am convinced that you need a sound theoretical background besides the practical training. You will not master HPLC (or any other field) after a short introduction of the kind "here is the instrument, just inject your samples and use a C18 column with water/acetonitrile, this system will separate everything". It may work for may separation problems but not for all of them, or it will not be clever for certain applications. In addition, you need to know the pitfalls of peak resolution and integration problems. It is simple, not only in chromatography but in all fields of analytical chemistry, to generate numbers. But the numbers must be accurate!

All photos from Swiss expedition team and guides.

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Morgan Freeman and the Agilent 5890

>> January 16, 2010

Nothing to coment, just had this screenshot and want to share. Morgan Freeman on Batman Begins, in theory, he analyse the drug used by Scarecrow.


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The almighty Flame ionization Detector

>> January 10, 2010

The FID was the very first detector in the very first chromatograph in the very first lab I worked. I even was there when it was installed. In that time, I did the classical question: “What does it ionize?”. And the install-GC-Guy said the molecules, it’s just like atomic absorption!
Well, now I know that’s not exactly true…
The source for ions in FID are the intermediates on the oxidation process, mainly the formylium ion CHO+.

This paper do a great job in simplify the yada, yada, yada from some publications in a simple and useful technical information.

Two of that I stress here, First: Anything with carbon tend to decompose to methane on the flame, and the reaction are very similar to my old post (if you didn’t read the post on the Thermoelectrical-chromatographer I say you should).

C2H2 +3H2 → 2CH4

Second: This is why the FID have an equal response per carbon, I mean, same amount of carbon ALMOST same response on detector. Now I can sleep happy.


To ilustrate the FID working, check the flash animation, you'll need flash player.

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Flash animation: Dr. Thomas "Red Head" Chasteen, Sam Houston State University.

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