Using TLC as analytical technique - USA vs Other countries?

[ender]

Comparatively speaking, is thin layer chromatography more commonly used as a quantitative technique in countries outside the USA or is its use as a quantitative technique the same across the various continents?

When I see publications that deal specifically with analytical TLC methods employing slit-scanning densitometers, video densitometry, automated sample application and development systems, they seem to be coming out of non-US labs. Furthermore, most of the articles in the Journal of Planar Chromatography appear to come from non-US labs, and most major conferences on TLC seem to have occurred outside the US.

Is there really such a bias to not using TLC as a quantitative technique in the United States, and if there is, what would be the reasons? Is it a matter of economics or is it tradition? What would be other factors that might create such a bias if it does exist?

- ender

[DSP007]

Good morning.

TLC method used by both the U.S. and other countries.
In the U.S. it is used relatively infrequently. The reason for the economic.

2% of the U.S. population consumes 25% of resources and produce 50% of the garbage on the planet, as the dollar is an international means of payment everywhere.

Therefore controlling the organization in the United States can afford to use expensive equipment, such as LC-MS solutions for trivial problems. Method of fire "from anti-aircraft guns on the wheel (a small bird)" certainly is not effective for the cost of transporting guns and ammunition, but allows for the luck to kill a bunch of sparrows with one shot for many miles. While under favorable conditions, can kill a sparrow tiny pebble from a slingshot, and th (rubber bands), but you need to know the habits of sparrows and the place where they can come up during feeding a few meters. It should be noted that if a fire does not know how, fatally unlucky or sparrows there's the gun will not help.


It is important to note that many companies producing equipment for HPLC have offices located within the United States. In addition, HPLC requires the use of standards, it is good business for the FDA.

There is another point. Work on the HPLC chromatograph as an operator can be a week to teach not only rights but also a monkey. Very stable type of device for reproducible results over time. This allows us to use for data collection is very low-skilled operator who can pay less.
And with TLC harder - the method must "feel" and this comes only with long practice.

In the European Union HPLC dragged lower, but the quantitative TLC is also not apply - the most well-known company in the field of densitometry is an American Kamaga.
Europeans are more like different types of spectroscopy, titration, although the HPLC and GC do not disdain.

Historically, WHO is actively promoting the TLC-considered that the use of this method is useful for finding gross counterfeit drugs and reduces the cost of backward African countries.

I came across the interesting work of Cubans.

About our business. During Soviet times, technical policy corresponded approximately to the current technical politki Europe, except for some nuances - the USSR in the 80 years refused to produce the NMR and was unable to master the manufacture of HPLC chromatographs except for the original UPLTS MiLiChrome.
Tech Culture for civilian enterprises electronics industry did not reach the level of production of precision products, and the military and without instrumentation were a lot of work. Therefore, HPLC was used little and is actively used by GLC (because there was a list of the serial range of gas chromatographs).

Now the technical policy is absent as such, one obezyannichine / copying others' actions without understanding the meaning - about how people imitate monkeys in the circus / - then under the United States is under the Europe.

However some are of use to quantify the TLC still remained from the days of SEV - see for example Sorbpolimer from Krasnodar.
Again, you can get in touch with a reputable Gennady Plahoniem (Garry) on anchem.ru

A very strong school of TLC was in University of Tartu (Estonia), Professor Miles has worked seriously and densitometry.
But with the destruction of the Soviet Union and Estonia's accession to the EU to all this came kaput. Estonia as a state was not viable - the customers for its industry had been in Russia and the raw materials it received from the same place. After separation of Estonians fell on bad times - they are so impoverished that was taken for metal scrap not only monuments in Tallinn, but all the copper wire grid ..

From "brothers-Slavs" - very strong developments in quantitative TLC were in Bulgaria (Sharshunova, Petets and Kopec) and Czechoslovakia.


Translation of Google, has not been edited. Therefore, for the ugly text - excuse.

[Consumer Products Guy]

I won't jump into US - Russian politics.

I'm in US, and I haven't used TLC for over 25 years. Reasons: HPLC is better at quantitation, and better at qualitative assessments too.

[unmgvar]

in the 50's in the space race both sides saw that pens could not be used,
so the US went on and invented a special space pen and along the way another 17 patented designs related one of which is helpfull for blind persons
the USSR went for the pencil

anyway in my view very early on, HPLC technology was far more superior in chromatography separation then TLC, and HPTLC came along only in the 90's commercially.
also automated technology related to those technologies was far better developed and easier to develop on the HPLC side
to this day the TLC equipment from the best manufacturer CAMAG is only semi automated at best eventhou these days it presents great results of precision and accuracy, stuff that was achieved already in the 90's by HPLC manufacturers.
the possibility to simply let the equipment run overnight is a very major point in favor of HPLC
also Camag has not been doing any serious development in the field of software and that has been especially in this decade very important.

also sensitivity is far better achieved on HPLC especially for the Nano scale which brings us to the coupling of MS to HPLC as well

so very fast HPLC would bring "faster", "better" and more automated, so it caught on easily in the analytical fields were it gave the benefits and added values.
Pharma for example with it billion $ industry simply turned it into a standard tool.
it is not so for other fields.
in the field of screening for drugs or other applications for examples I know that many police labs all over the world use TLC equipment and even simple manual TLC for faster screening results and not HPLC.
it all depends what you do and what you need,
but you have to admit HPLC is in many cases by far a better choice for the job at hand
and with a stronger need of "fire and let go" philosophy HPLC is there to stay

[DSP007]

I won't jump into US - Russian politics.

I'm in US, and I haven't used TLC for over 25 years. Reasons: HPLC is better at quantitation, and better at qualitative assessments too.

Simple economics determines the technical capabilities and resources. But the economy is determined by internal economic politics ( but politics determinate by morality ).

In general, the country is not a "dictator" in a particular field is advantageous to use alternative technologies.
Therefore, the European and British Pharmacopoeia (in Europe there is a complete production cycle of HPLC and a base of standards like FDA) using HPLC with respect to less than the American and Japanese Pharmacopoeia, and more likely to use spectroscopic and titration methods.

Since ender asked how things are outside the U.S. - I told him as we do. If anyone is in Western Europe, China, India or other countries tell how they have.

Comparatively speaking, is thin layer chromatography more commonly used as a quantitative technique in countries outside the USA or is its use as a quantitative technique the same across the various continents?
.........................................................................................................................
- ender

[DSP007]

anyway in my view very early on, HPLC technology was far more superior in chromatography separation then TLC, and HPTLC came along only in the 90's commercially.
also automated technology related to those technologies was far better developed and easier to develop on the HPLC side
..........................
so very fast HPLC would bring "faster", "better" and more automated, so it caught on easily in the analytical fields were it gave the benefits and added values.
Pharma for example with it billion $ industry simply turned it into a standard tool.
it is not so for other fields.
in the field of screening for drugs or other applications for examples I know that many police labs all over the world use TLC equipment and even simple manual TLC for faster screening results and not HPLC.
it all depends what you do and what you need,
but you have to admit HPLC is in many cases by far a better choice for the job at hand
and with a stronger need of "fire and let go" philosophy HPLC is there to stay

100%+

However, TLC has some advantages.
Certainly not in question "go there, I do not know where, bring it, I do not know that." In this matter by HPLC-MS - out of competition.
About the automatic anti-aircraft gun in front of a slingshot.

Although it should be noted, that for highly qualified as an expert chemist and with TLC, you can work - most work 60-70h on the biochemistry of steroids and lipids are made by using TLC as a separation method.

TLC has a significant advantage when we have to work with an obvious crap, for instance pitched synthesis intermediates, which ubyut any column.

Also TLC has an advantage when you need a clear result - for example, examination of the court. Although "not entirely reliable" picture will convince the judges better than a lot of absolutely accurate market with accurate peaks.

[bgranot]

Comparatively speaking, is thin layer chromatography more commonly used as a quantitative technique in countries outside the USA or is its use as a quantitative technique the same across the various continents?

When I see publications that deal specifically with analytical TLC methods employing slit-scanning densitometers, video densitometry, automated sample application and development systems, they seem to be coming out of non-US labs. Furthermore, most of the articles in the Journal of Planar Chromatography appear to come from non-US labs, and most major conferences on TLC seem to have occurred outside the US.

Is there really such a bias to not using TLC as a quantitative technique in the United States, and if there is, what would be the reasons? Is it a matter of economics or is it tradition? What would be other factors that might create such a bias if it does exist?

- ender

There is good auotomated instrumentation for TLC like CAMAG. TLC is relatively 'green' and less expensive than HPLC. I wish thay would use it in the US more often. Most things can be run on HPLC, but TLC is 'too simple' for US to use.

[lmh]

2d-tlc is easy, 2d-hplc quite hard.

[ender]

Thanks for everyone's responses, very interesting.

In regards to TLC versus HPLC, there's little point in debating which is the better analytical technique. HPLC is far superior for almost all applications, but I can think of a couple situations where TLC has an edge.

You can have components so strongly retained on a HPLC column that you will never see them in an HPLC analysis. For example, if you were making synthetic dyes that had oligomeric impurities, those impurities might never elute and might stay on the HPLC column. HPLC analysis would not detect such a impurity but TLC would in that you'd see the impurity stay at the origin where you spotted the plate.

This is true at the other extreme also. If you have very weakly retained components on the HPLC column, those impurities could be masked by the solvent front of the injection onto the column which almost always causes a large baseline disturbance. Again, this is something that TLC could detect while HPLC cannot. Those two cases are a difference in sensitivity that favors of TLC over HPLC. TLC can give you a very visual picture of the whole sample, something other chromatographic techniques often lack.

TLC also allows multiple samples to be run in parallel in the same chromatographic run, which is something you cannot do with HPLC. That in itself is a significant advantage in terms of sample throughput and visualization.

Modern complex instrumentation such as HPLC, LC/MS, GC, GC/MS etc. tends to raise the level of automation to the point that the analyst simply points a sample vial in a tray and pushes a button to do the analysis. The data is then picked up from the printer and your done with the data collection phase.

TLC requires much more skill and attention to get good data in the first place, and while that is a negative in a business environment, it's a good thing for those who have an appreciation for developing those skills.

Let me put it is way. If they invented a golf club that guaranteed anyone could shoot par, golf would loose it's appeal. Overcoming challenge has it's own reward, and if you're able to gain independence from the need for expensive instrumentation and actually be able to answer questions, that's practicing the art of science in my opinion.

- ender

[bgranot]

Thanks for everyone's responses, very interesting.

In regards to TLC versus HPLC, there's little point in debating which is the better analytical technique. HPLC is far superior for almost all applications, but I can think of a couple situations where TLC has an edge.

You can have components so strongly retained on a HPLC column that you will never see them in an HPLC analysis. For example, if you were making synthetic dyes that had oligomeric impurities, those impurities might never elute and might stay on the HPLC column. HPLC analysis would not detect such a impurity but TLC would in that you'd see the impurity stay at the origin where you spotted the plate.

This is true at the other extreme also. If you have very weakly retained components on the HPLC column, those impurities could be masked by the solvent front of the injection onto the column which almost always causes a large baseline disturbance. Again, this is something that TLC could detect while HPLC cannot. Those two cases are a difference in sensitivity that favors of TLC over HPLC. TLC can give you a very visual picture of the whole sample, something other chromatographic techniques often lack.

TLC also allows multiple samples to be run in parallel in the same chromatographic run, which is something you cannot do with HPLC. That in itself is a significant advantage in terms of sample throughput and visualization.

Modern complex instrumentation such as HPLC, LC/MS, GC, GC/MS etc. tends to raise the level of automation to the point that the analyst simply points a sample vial in a tray and pushes a button to do the analysis. The data is then picked up from the printer and your done with the data collection phase.

TLC requires much more skill and attention to get good data in the first place, and while that is a negative in a business environment, it's a good thing for those who have an appreciation for developing those skills.

Let me put it is way. If they invented a golf club that guaranteed anyone could shoot par, golf would loose it's appeal. Overcoming challenge has it's own reward, and if you're able to gain independence from the need for expensive instrumentation and actually be able to answer questions, that's practicing the art of science in my opinion.

- ender

You can use the same vials you use for HPLC using CAMAG outo-sampler, CAMAG Developer and CAMAG scaner to do your TLC and you have the same automation like HPLC including chromatography data system and have chromatograms just like HPLC. This is 2011 not 1950.
PS I am not working for CAMAG

[ender]

Would buying such a system (CAMAG auto-sampler, CAMAG Developer and CAMAG scanner) cost substantially less than buying an HPLC?

- ender