What is the poster presenting and why?
The poster is presenting a sophisticated chromatographic based method that ensures a specific and sensitive detection of compounds or substances like β-blockers through the use of ACQUITY UPLC FLR detector that ensures optimization of excitation and emission wavelengths of β-blockers. It takes a lot of time taken to complete the process because the separation and sensitivity criteria are high if a conventional UPLC protocol is used. In order to overcome this time factor, and ensure much specific and sensitive method of detection, an up-gradation of equipment may be necessary.This is accomplished by the ACQUITY UPLC FLR detector as it allows to obtain quick and significant results. Briefly, for fluorescence-based applications, ACQUITY UPLC® Fluorescence (FLR) Detector is very much reliable ®. The advantages inherent with the UPLC technology can be provided to any substance with fluorescence or phosphorescence properties, vitamins, drugs of abuse and polynuclear aromatic hydrocarbons (PAHs) (“ACQUITY UPLC Fluorescence Detector: Getting Started Guide.”). Describe the instrument in Figure 2 based on the major categories discussed during the lecture [source(s), wavelength selector(s), and detector(s)]. In the figure 2, there is a mercury-xenon arc lamp located in the lamp housing unit of FLR detector equipment. The lamp produces a spectrum of light of a given intensity in the ultraviolet (UV) and visible ranges. Mercury-xenon arc lamps serve as common broadband excitation light sources, and at certain emission bands, they have benefit of higher fluorescence intensity (“ACQUITY UPLC Fluorescence Detector: Getting Started Guide.”). The wavelengths used are of different nanometers. These include 215 nm, 243nm, 305nm, and 350 nm. These are excitation wavelengths and the selector is a excitation grating monochromator. Briefly, monochromator is a device used for selecting wavelengths and grating monochromatic utilizes; this diffraction grating allows the wavelengths of the specific range to pass. Since the excitation is selected by monochromator, emission wavelength is also possible. Thus, in the figure 2, emission grating is also present the selected emission wavelengths. These are 405 nm,325 nm, 495 nm, and 397nm. Acquity UPLC FLR detector is a multichannel, tunable, fluorescence detector which operates from 200 to 900 nm. The detector is functional through its optical and electronic design that involves optics, selected wavelengths and test flow cell and Electronics. Optics or detector optics would mean the following Mercury-xenon arc lamp, two ellipsoidal mirrors and one parabolic mirror, wavelength calibration filter, and second-order filter, shutter, entrance slits and exit slits, Photomultiplier tube (PMT) and Waters axially illuminated flow cell. Electronics may imply lamp and dc power supply.
Which detector provides the greatest detection sensitivity for the β-blockers?
Flourescent Liquid chromatography coupled to photodiode-array UV detection has the greatest detection sensitivity for the β-blockers. Which β-blocker would provide roughly the same quantitative results (within 40%) for a sample when using UV absorbance or fluorescence? Labetalol would provide the same quantitative result because the peak observed from the figures 6 and 7 is almost the same, corresponding to the signal to the noise ratio (S/N).
How did the scientist define LOD and LOQ, and how could their definition be compared to what was discussed during the lecture?
The scientist defined the LOD (Limit of detection) as 3 x s/n indicating that signal to noise ratio of three is an index for determining or estimating LOD and LOQ (Limit of quantification) as 10 x s/n indicating that signal to noise ratio of ten is an index for determining or estimating LOQ. All the beta blockers subjected to the measurement varied by analyte concentration that corresponded to the signals and noise ration and found to be more sensitive for FLR detection. Hence, from the lecture, it is clear that cartelol does not fluoresce, and oxprenolol has excessive noise. Why did a chromatographic method develop a “long and tedious” process? This is because the preparation of analytes is done as per the protocol where the mobile phase elution with the analyte and the retention time of the final analyte to be estimated contribute to a “long and tedious” process. What tool(s) did the scientists use to simplify the process? They applied UPLC FLR detector as it could make the detection of the analyte easier due to its increased sensitivity and specificity.
Bibliography
ACQUITY UPLC Fluorescence Detector: Getting Started Guide. n.d. Web.