Two in One Fluorescence Absorbance Spectrometer

Interview conducted by Stuart MilneMay 21 2018

Cary Davies, Global Product Line Manager, Fluorescence Division, talks to AZoM about the new Duetta two in one fluorescence absorbance spectrometer.

Where is the Duetta positioned in a market full of fluorescence instrumentation?

Duetta is targeting a new space for HORIBA. Our other fluorescence instruments are really targeted for the high-end research community and that's where we're very well known, but Duetta for us is a new entry level fluorometer that's really targeted for the mid-market for spectrofluorometry, and also the analytical market.

Why have HORIBA developed a two in one fluorescence absorbance spectrometer?

When we looked at the mid-market and we decided we wanted to introduce a product into that space, we really felt that it was important for us to deliver a product that was going to offer more value than the products that were currently available. There's a number of instruments and a number of companies that are offering products in that space, but all of them are single purpose, single function instruments. We felt that we could deliver a product in the same kind of price range as the competitors, but offering both fluorescence and absorbance. This would be tremendously helpful. Most labs that have a fluorometer, but they also have a UV VIS absorbance system somewhere on the bench nearby that they do occasionally use, just simply to look at absorbance. We were fortunately able to make that goal happen with Duetta being a two in one fluorescence and absorbance spectrometer.  With the Duetta, there’s no need for additional fluorescence or absorbance spectroscopy equipment.

How does Duetta compare to traditional fluorescence and absorbance spectroscopy instrumentation?

First is the two in one aspect - that's very different than other instruments that are out there - but there are other things that also make this system very unique and very different.

First, and foremost, for fluorescence we are using a CCD for detection of the emission spectra. All of the other instruments in this space have a single channel PMT and they scan the emission monochromator. What we're able to do with this detection technology is to collect the entire emission spectrum in 50 milliseconds. So Duetta can collect data much faster. This in particular is a big differentiator between Duetta and a traditional scanning spectrofluorometer.

The CCD also gives us the advantage of being able to detect further in the near infrared than we can with a traditional PMT. These PMTs typically (unless it's an extended and very expensive extended NIR PMT) cut off at around 850 or 900 nanometers, whereas the CCD is able to measure all the way to 1,100 nanometers.

So Duetta opens up the possibility of working with NIR probes and, also provides a better molecular fingerprinting with extended experimental dynamic range.

How does simultaneous absorbance-transmittance fluorescence excitation emission matrices (A-TEEM) provide better molecular fingerprinting and extended dynamic range?

The HORIBA A-TEEM technique is a variant of an EEM, which stands for an excitation emission matrix, also known as a three dimensional plot. EEM’s are used with Spectrofluorometers to look at a so called molecular fingerprint by scanning the emission wavelengths and then adjusting the excitation wavelength to construct an excitation versus emission plot. This is an EEM. All spectrofluorometers are able to collect an EEM.

Duetta can collect this entire EEM in seconds as opposed to maybe the 40 minutes or an hour it takes with a scanning fluorometer. That's a huge difference and a great benefit. However, we're also incorporating the measurement of absorbance at the same time because of the 2 in 1 design of the instrument. We then use the absorbance data to do a correction of the fluorescence signal for the inner filter effect, which is a well-known physical phenomenon that distorts the fluorescence signal at increasing sample concentrations. We call this technique A-TEEM, for Absorbance-Transmission Excitation Emission Matrix.

By correcting for inner filter effect, the A-TEEM molecular fingerprint is a much more absolute representation of the true molecular fingerprint, and therefore when we use multivariate analysis software the A-TEEM data gives us much better component analysis than can be achieved with just a simple EEM.

What type of scan speeds are you able to deliver?

We're talking about scan speeds that are obscene by current standards, so you're able to collect the entire emissions spectrum from 250 nanometers to 1,100 nanometers with a 50 millisecond acquisition time. It's orders of magnitude faster than we're able to do with a scanning spectrofluorometer.

In a recent press release you stated that the Duetta™ represents the new future of analytical bench-top fluorescence instrumentation. Where do you see the Duetta making the biggest difference?

I think it'll make a big difference in two ways. One, is in the research community where people need to do routine fluorescence measurements. I think that the Duetta is really a great product for them to take a look at. Their work flow will be a lot easier, it will be a lot faster. It's doing some things that they can't do with a traditional fluorometer.

We do believe that the analytical space can benefit also. In terms of QCQA, Duetta will really have a good opportunity of penetrating that market space. That's not a space that the HORIBA fluorescence product line is well known in and we believe this will give us an opportunity to really introduce the product into that space.

What level of fluorescence sensitivity can the Duetta™ achieve?

When we designed it we really wanted an instrument that was also highly sensitive. It doesn't really do you much good to have a very fast fluorometer, if it doesn't have the sensitivity to deliver on that speed. Without good sensitivity, it doesn't matter how fast things are, you're going to have to slow down your acquisition to really get a good signal. With Duetta, we have delivered best in class sensitivity in this mid-market space. We still manufacture high end research instruments which do deliver a higher level of fluorescence sensitivity, but in this class of fluorometer we have the highest guaranteed specification.

How does the new EzSpec software provide an easy, user friendly interface for users?

In addition to really having a different optical design, we introduced a new software platform for this instrument as well. It's called EzSpec, and we really started from scratch with the architecture and the design. We did a lot of focus groups, and we also have a lot of experience with fluorescence spectroscopy, so we delivered a much more intuitive interface, almost like a mobile application. It has push button applications and a much more welcoming interface for a student, undergrad, or anyone to approach the instrument and to work with it. The work flow is very simple and straight forward and so far, the feedback has been really good.

How has the market responded to the Duetta™?

We're just introducing the instrument now and it's really been exciting. The feedback has been tremendous. We have some wonderful quotes from customers. We're very excited and here at Pittcon we were really honored to have received the gold award for innovation for Duetta. It's a real indicator that people are excited about the product.

What was the response like at Pittcon 2018?

Obviously Pittcon is a premier event. It's an important event for the industry, certainly for HORIBA as it is for many other companies. Winning the gold award for innovation for this product, is really rewarding. With all of the work that's gone into it, for the team to see this recognition, it's very important for us.

About Cary Davies

Cary Davies is the Global Product Line Manager of the Fluorescence Division of HORIBA which has a long history of fluorescence innovation through the many fluorescence companies that are now part of the HORIBA family including SPEX, Jobin Yvon, SLM, IBH and PTI. Cary joined HORIBA after the acquisition of PTI by HORIBA. He brings with him extensive knowledge of product management, development, marketing and sales of fluorescence instrumentation having previously worked with PTI and Optical Building Blocks Inc. (OBB) for 25 years.