One of the hottest analytical tests to enjoy. What

Abstract: in major colleges and universities, there are such a group of people, although they do not have the title of Professor, although there is no SCI article attracting the attention of scientific researchers, they have been silently paying. Although there have been complaints and regrets, they have paid silently and enjoyed it in their work and life of "pain and happiness" Dr. Guan Yan of Peking University analysis and testing center is one of them

in major colleges and universities, there is such a group of people, although they do not have the title of Professor, although they do not have SCI articles attracting the attention of scientific researchers, they have been silently paying. Although there have been complaints and regrets, they have paid silently and enjoyed it in their work and life of "pain and happiness" Dr. Guan Yan of Peking University analysis and testing center is one of them

Dr. Guan Yan from the analysis and testing center of Peking University

Guan Yan began to have "close contact" with the molecular fluorescence spectrometer after her Ph.D. graduation in 2009. According to her introduction, from the initial simple use of instruments to the current "DIY", Guan Yan has established a deep relationship with the molecular fluorescence spectrometer. She believes that the molecular fluorescence spectrometer is no longer a cold instrument, but a "friend" who can provide objective and detailed data. Guan Yan said that she likes her current work very much

today, we will walk into the analysis and testing center of Peking University, approach the front-line analysis and testing personnel, and listen to Guan Yan talk about the stories with the molecular fluorescence spectrometer

"niche" instruments, no longer the application of "niche"

when it comes to molecular fluorescence spectrometers, Guan Yan also admitted that compared with mass spectrometry, chromatography and other analytical instruments, such instruments are slightly "niche". "Most of the time, molecular fluorescence spectroscopy is only used to characterize the luminescence properties of materials, but not all materials emit light, which also affects its application to a certain extent." Guan Yan explained

however, although it seems to be "niche", with the development of scientific research needs, the application scope of molecular fluorescence spectrometer is also expanding, and its role is becoming more and more obvious. "In the past, when doing compound research, we often started with the analysis of the composition and structure of the sample, and then extended to the study of properties, especially the study of biological probes. The basic luminescence and physical properties must be clear before they can be used in applications. In this case, the molecular fluorescence spectrometer has more potential."

not only that, according to Guan Yan, in recent years, with the expansion of instrument functions, the user group of molecular fluorescence spectrometer is also gradually growing. "In the past, most users of molecular fluorescence spectrometer used to do material research. Now it has been extended to many disciplines, including new energy, lighting and coordination chemistry, cell biology, etc. the test content is also expanding. For example, many users of biology have been extended to the use of fluorescent lifetime for biomarkers and their state analysis in organisms, as well as the use of environmental colleges, earth and space colleges, mining and archaeology, and even in the near future Scientific researchers specializing in Formula 1 Racing have begun to use it. It is hoped that molecular fluorescence spectrometer, like electron microscope, will be used in more disciplines as a highly sensitive scientific research characterization tool

"Moreover, it is worth mentioning that many scientific researches do not stop at the preparation and basic performance characterization of a material, but pay more attention to its practicality and functionalization. Luminescence is a representative functional application, and accordingly, many materials with luminescence properties have the need to be tested. Not only that, in recent years, materials that were previously considered by classical physics to be non luminescent or weak luminescent have also been re tested, such as nano Silicon, graphene quantum dots and carbon quantum dots. "

as far as the analysis and testing center of Peking University is concerned, it is currently equipped with 9 molecular fluorescence spectrometers, involving 5 brands, of which Dr. Guan Yan is mainly responsible for the nanolog fluorescence spectrometers and deltaflex fluorescence lifetime testing system of Horiba company. In terms of responsibilities, these two instruments first assist the teaching and scientific research of the University, and also connect samples. The research objects involved include quantum dots, up conversion materials, fluorescent phosphors, perovskite and other types. "Basically, there are many applications in various fields of chemistry, and at the same time, under the trend of interdisciplinary, samples from biology, environment, geology and other fields also come in an endless stream."

nanolog and deltaflex

they pay more attention to these key points when choosing molecular fluorescence spectrometer

what are the key points in choosing a suitable molecular fluorescence spectrometer? For the analysis and testing center of Peking University, Guan Yan analyzed the following factors, including instrument performance and instrument operation

"as we are a platform, the overall requirements are that the performance should be better on the basis of full functions. However, if the large and all are not as good as the small and fine, we will choose the latter to ensure its professionalism." Guan Yan introduced

it is reported that when purchasing the fluorescence life test system, Guan Yan compared several manufacturers. Finally, deltaflex of Horiba also considered many factors, including simple operation of the instrument, good corresponding configuration performance, and various expansibility

"among them, light source, detector and timing unit are three key factors: a set of equipment covers the test range from picosecond to second; it is equipped with detectors in UV visible region and near-infrared region; in addition, the response speed of timing unit also determines the accuracy of the test, and the test rate meets the expectation."

"in terms of the function of the instrument, we think more about the progressiveness and foresight of the instrument. When we expand the function, it is not convenient to carry out it, and whether it is compatible with the existing equipment."

"moreover, from the perspective of University procurement, it also has a lot to do with funds. In terms of the current service object and capital level of the analysis and test center, we pay more attention to the performance of the instrument, such as the parameters of key components such as grating and detector, as well as the signal-to-noise ratio and stability." For example, Guan Yan said, "in terms of near-infrared detectors, there are single-point PMT and IgA (indium gallium arsenic) CCD detectors, and we chose the latter. Because for samples with strong fluorescence, there is not much difference between single-point and area scanning, while for samples with very weak fluorescence, such as the classification and classification of single-walled carbon nanotubes, the advantages of the latter appear."

only by playing with "small" parts can the instrument be used incisively and vividly

for front-line analysis and testing personnel, using the instrument and using the instrument well are actually two levels of problems, and Guan Yan's requirements for herself are how to use the instrument incisively and vividly

he said, "every analyst and tester, even the students who come to deliver samples, have no problem operating the instruments. However, we are more concerned about how to measure the samples well. There are not only some skills and the determination of experimental parameters, but also the research on some 'small' components will often bring unexpected results to the experiments, and even solve the problems that have plagued us before."

the eyes that these "small" parts need to be found

during the interview, Guan Yan talked about her beloved instrument, and we really felt her love for this job. Guan Yan also introduced her experience in using the nanolog and deltaflex systems she is responsible for, especially the "big" use of many "small" components

according to Guan Yan, many times people may pay more attention to the key components and detection methods of molecular fluorescence spectrometer such as grating and detector, but some special functions of the instrument are often ignored. For example, the "front face" on nanolog seems to be just a small button, but it has magical effects on high scattering samples and samples with particularly strong self absorption. Guan Yan explained that in the "front face" mode, the light path only hits the front surface of the sample, which is detected by the reflection mode, and then the signal is collected. For samples with strong self absorption, it is possible to get a perfect data by changing a button

moreover, when making the fluorescence lifetime, careful observation will find that the liquid in the deltaflex sample tank is placed vertically, while the solid is inclined. Is this reasonable or carefully designed? Guan Yan said that for solid samples, the suppression of stray light is very important, and a certain angle of design can well weaken or even avoid the interference of stray light. Not only that, the solid sample tank so designed can also be adjusted according to the thickness and height of the sample, which is convenient for the testing of various samples, especially suitable for multidisciplinary urban greening consumables, etc.). "Sometimes it's not that the samples are difficult to measure, but that we don't make full use of the conditions created by the instruments."

"one of the advantages of these two molecular fluorescence spectrometers is that they can 'DIY' in many places, leaving many possibilities for scientific research. This is also what we prefer, such as the open sample bin, which can be equipped with different detectors and lasers."

future development direction of molecular fluorescence spectrometer: functional expansion, online, etc.

many people mentioned that compared with other analytical instruments, the launch speed of new products of molecular fluorescence spectrometer is relatively slow. For this, Guan Yan said, "Molecular fluorescence is the most compact instrument, the light path is determined, and the light source is basically the only consumable. Moreover, from the current manufacturing process and performance, components such as gratings are very durable, which also leaves the impression of slow renewal to a certain extent."

does that mean that the molecular fluorescence spectrometer has reached the bottleneck stage? Guan Yan said that although it is relatively stable for the instrument host at present, it has a good development prospect in terms of functional expansion, online and so on

on the one hand, at present, the incident light spot is relatively large no matter whether the xenon lamp slit is inserted or the optical fiber is introduced. Such a light spot size results in the average value of the whole sample. If you want to see a single crystal, micro area detection is very important, which involves the combination of microscope and so on

on the other hand, in terms of accessories, the molecular fluorescence spectrometer has not stopped moving forward, which is also the place where users have the highest voice, including light source, detector, plug and play accessories, accessory coupling without too much adjustment, micro sample pool, variable temperature accessories, etc. "From small accessories to large accessories, the current requirements for functional accessories are increasing. We hope that the instrument has more functional accessories that meet the needs, or reserve more interfaces to meet the needs of DIY." In view of this, Guan Yan also stressed that "when matching accessories, we not only need the perfect coupling of hardware from various manufacturers, but also the software is more important. We hope to open more functions."

of course, there is no need for special foundation when installing the main body of Jinan experimental machine and dynamometer. On the basis of the instrument itself, Guan Yan is also trying to improve a series of instruments and accessories. For example, by adding a pulse width control module, the semiconductor laser can be applied to the up conversion life test, which is particularly important for the luminescence analysis of pulse width sensitive up conversion materials

in addition, in terms of the use of the instrument, Guan Yan said that there are several problems worthy of attention: the most important is the calibration of the instrument