[REVIEW] For many people, perhaps the MPT is not a very familiar term. Actually, it is a completely independent intellectual property rights of Chinese technology,   is a new type of atomic spectroscopy lighting source pioneered by  Dr. Jin Qinhan research group  in 1985, and  achieved a hundred-watts MPT spectrometer commercialization in 1999.

MPT, microwave plasma torch. For many people, MPT is not a very familiar term. Actually, it is a completely independent intellectual property rights of Chinese technology,   is a new type of atomic spectroscopy lighting source pioneered by  Dr. Qinhan Jin research group  in 1985, and  achieved a hundred-watts MPT spectrometer commercialization in 1999.

September 4, 2013, MOST announced   "major national scientific equipment development projects - 2013 proposed  Projects ", which is borne by the SUPCON "kilowatt MPT spectrometer developed". What is the difficulties between the kilowatt-class products and the previous hundred watt-class products ? Comparing with ICP (Inductively Coupled Plasma Spectrometer) and other instruments ,hat advantage does MPT have? To this end, the instrument information network editor interviewed Dr. Qinhan Jin who is  working in Zhejiang University, asking him to introduce the advantages of MPT and future prospects.

Dr.Qinhan Jin- Zhejiang university

From hundred watts class to kilowatts-class: "Our kilowatt MPT is much different from Agilent MP "

In 1985, Jilin University Jin Qinhan research group pioneered a new microwave plasma excitation light source -MPT;

In 1996, Jin Qinhan group in cooperation with the Beijing-light instrument company successfully developed the world's first single-channel sequential scanning MPT atomic emission spectrometer;

1999, Changchun Jilin university- Cygnet Instruments ltd.  realized the MPT spectrometer commercialization;

2000, Jin Qinhan group undertook  the state support program "MPT spectrometer of development", and successfully developed in 2003;

In 2011, MPT spectrometer achieved  commercialization  in SUPCON as a teaching instrument;

2013, SUPCON "kilowatt MPT spectrometer developed" selected by  "national major scientific equipment development projects -2013  proposed Projects."

Jin Qinhan achieved hundred watts -class MPT spectrometer industrialization before, what made it decide to develop kilowatt-class instruments ? Dr.Jin  explained, "Precious  industrialization hundred watts MPT spectrometer has been working at low power, in this case, it’s difficult to guarantee the stability of the plasma when the sample solution is atomized direct injection, thereby there is problem  of desolvation which require heating, evaporation and other steps that is  too much trouble, so it currently can only used as a teaching instrument. However, this problem will be solved once the power increased to kilowatts. The biggest reason  Why not kilowatt  instruments developed before is that there is no suitable high-power microwave source. " In 2011,Agilent introduced kilowatt MP-AES that stimulated Jin Qinhan, he said," I thought , We Chinese people have own MPT technology, why don’t  we  make kilowatt instruments it? "

At the same time, Dr.Jin stressed that, "what we  do kilowatt MPT is completely different from Agilent instrument t, we are not follow, but innovative. Agilent uses  quartz tube, magnetic coupling, rectangular waveguide under nitrogen condition.; Our  torch can use copper, nitrogen, argon, or helium. "Then he introduced" nitrogen and argon plasma can be formed in a quartz tube, but is difficult to obtain helium have Spectroscopy Value of the high-density plasma, because helium is very small molecular weight, once a plasma is formed, the diffusion rate is too fast, it will instantly fill the quartz tube, the plasma density is not high number, the probability of collisions between the particles will greatly reduce the small, such a thin plasma excitation source is not ideal, the same reason with helium ICP application has not been successful. "

"There is another difference, Agilent MP-AES fixed 1200W, not adjustable. And from the application point of view we consider that a fixed power would not be suitable for all elements in the best conditions, and therefore will set more parameters can be adjusted , power from 100W to 1500W continuously adjustable. "

Kilowatt MPT Development  difficulties:  microwave source and  torch

How much difficult to let MPT rose from  hundred watts to  kilowatts? Dr.Jin  introduced , "the above-mentioned  microwave generator is the problem should be solved first. High stability requirements for microwave generator that used in spectrometry equipment, and now  thousand watts of microwave generator are mostly for industrial use in the market, stability is low. In the major projects, there are special criteria for microwave generator stability , our goal is to achieve stability thousandth. In cooperation study with American Dr. Hieftje  , magnetron  microwave generator stability  has reached six thousandths, our target is increasing thousandth on the basis. Some time ago there is a company in Sichuan say you can do it two hundred, we will further increase to one-thousandth of their basis. "

"In addition, last June, in Canada microwave oven exhibition, the microwave oven of a well-known company exhibited the first all-solid-state microwave oven in the world. It is understood that they have done a 600W. With respect to the magnetron microwave generator , a much better all-solid-state microwave generator stability, and it can be operated at low pressure. We are now working with the company to discuss cooperation, and hope to further increase the power, to develop a high level of stability kilowatt solid-state microwave generator. "

In addition to the microwave source, the torch is a difficulty. Dr.Jin introduced , "we are using a copper torch, no problem  when used under a hundred watts, but after the power is increased to the kilowatt level positions, long-term Use heat problem occurs  if the torch fittings can not handled properly  to form a microwave reflector. "For that matter,Dr.Jin  mentioned that they has taken a series of improvements, such as changing capacitive coupling to conductive coupling, the future will continue to improve to ensure instruments with long-term stability.

Although there are various aspects of the above difficulties, Jin Qinhan remain confident, he said, "MPT is of a completely independent intellectual property rights of technology, we have a scientific basis and technical reserves. Now the full support of Zhejiang University, SUPCON also ready to set up a project company for this project. I am not saying that we can do the best, but I believe that working with our entire project team, the project goal is fully realized. "

Outlook: "I hope MPT can replace ICP in the near future"

Comparing with  MPT, ICP is more familiar to industry insiders currently. According to Dr.Jin introduction, "current import ICP mainly using solid-state high-frequency power, stability is one-thousandth." So, what is the advantage do MPT has for ICP? In response, Dr.Jin said, "can be expected, , MPT will do what ICP can do currently; ICP can not be directly introduced into the air samples, but  MPT  can be achieve that air directly into the sample analysis; helium ICP has not  been able to practice so far, while helium MPT can be realized in less power. I believe kilowatts MPT will create conditions  for achievement of "full element" analysis, for future MPT is expected to take over ICP! "

Then Dr.Jin details the many advantages of MPT, "Because of the way to get the structure and coupled plasma apparatus are different, ICP is through open loop coupling coil obtained by inductively coupled plasma, electromagnetic waves can not all be absorbed by the plasma , MPT is working in a resonant cavity, as long as tuned properly, almost all microwave energy can be used by plasma, that MPT's energy efficiency is much higher than ICP, 1200W of MPT is expected to reach 1600W ICP results. "

"ICP can only work with argon, and MPT can use argon, nitrogen, helium three gases work. If time working with argon ICP's performance is quite MPT and then work with helium, MPT's performance Obviously it will be over the ICP. "

In terms of sensitivity, Dr.Jin introduced , "100W of MPT with desolvation system for the detection sensitivity of many elements can reach ppb magnitude, analyze the performance of kilowatt MPT is clearly comparable with ICP. In addition, compared with AAS (atomic absorption spectrometry), MPT sensitivity is not bad. Furthermore, AAS can only measure one element, MPT can achieve sequential scan or a full spectrum of direct-reading, test all the elements at the same time, but at the time of the order of scanning measurement required just a little larger sample. "

In the application, "MPT enables direct and continuous real-time monitoring of the atmosphere, but also the organic components, such as oil samples were analyzed directly nebulization detected that  ICP is  difficult to achieve. In addition, high-temperature alloys Central Africa detection of metal elements, ICP encountered difficulties (ICP detection halo to the conditions under vacuum ultraviolet), and MPT with helium at atmospheric pressure under ordinary visible and UV spectral region solving problems , comprising detecting halogens. "Further ,Dr.Jin also introduced that the major projects is also equipped with a powerful application development units, such as the China Iron and Steel Research Institute Group, Northwest Institute of Nuclear and other technologies, they are mainly responsible for MPT Spectrometer development in related industries and standard construction work.

For the price we are generally concerned about,Mr.Jin said, "MPT price not more expensive than the ICP!" In addition, he also stressed, "MPT is the Chinese people's creativity, but also has the above advantages  compared to ICP, we have no reason not to do it well. "