Fluorescent detection, format

C) Externally standardized RT-PCR with online-detection using specific hybridization probes this detection format is based on various fluorescence detection formats, e.g., fluorescence resonance energy transfer (ERET). 

Hosokawa, C., Yoshikawa, H. and Masuhara, H. (2004) Optical assembling dynamics of individual polymer nanospheres investigated by singleparticle fluorescence detection. Phys. Rev. E, 70, 061410-1-061410-7 (2005) Cluster formation of nanoparticles in an optical trap studied by fluorescence correlation spectroscopy. Phys. Rev. E, 72, 021408-1-021408-7. 

A variety of formats and options for different types of applications are possible in CE, such as micellar electrokinetic chromatography (MEKC), isotachophoresis (ITP), and capillary gel electrophoresis (CGE). The main applications for CE concern biochemical applications, but CE can also be useful in pesticide methods. The main problem with CE for residue analysis of small molecules has been the low sensitivity of detection in the narrow capillary used in the separation. With the development of extended detection pathlengths and special optics, absorbance detection can give reasonably low detection limits in clean samples. However, complex samples can be very difficult to analyze using capillary electrophoresis/ultraviolet detection (CE/UV). CE with laser-induced fluorescence detection can provide an extraordinarily low LOQ, but the analytes must be fluorescent with excitation peaks at common laser wavelengths for this approach to work. Derivatization of the analytes with appropriate fluorescent labels may be possible, as is done in biochemical applications, but pesticide analysis has not been such an important application to utilize such an approach. 

Based apparently on the same principle as described above, suitable but rather expensive kits exploiting monovalent Fab fragments to block endogenous tissue immunoglobulins have also been developed commercially, such as Mouse-on-Mouse (M.O.M. ) Kits by Vector Laboratories (http //www.vectorlabs.com/). Three Vector M.O.M. kits are available. These kits use the same blocking technology and biotin-avidin detection format, but offer a choice of using either an enzyme-based or fluorescent-based visualization method. 

AB-labelled oligosaccharides are resolved in 50 pi 65% acetonitrile/35% 80 mM ammonium formate (pH 4.4). Aliquots (50 pi) of 1 10 diluted samples are injected onto the HPLC column. Analysis of the eluate is carried out by fluorescence detection (excitation at 330 nm, emission at 420 nm). Peak fractions are further investigated by mass spectrometry. 

Since TCs form highly fluorescent chelates with metal ions at the appropriate pH value, their complexation with 5% zirconium chloride solution added postcolumn to the eluate from HPLC was used for fluorescence detection. The highest yield of fluorescence was observed at pH 2.0 therefore a pH adjustment of the mobile phases was necessary (25-27). Moreover, using a mobile phase of pH 2.0, the formation of both the C4 epimers and anhydroTCs are minimized. 

Steroids (neutral or conjugated) and their dansylhydrazine derivatives Polyacrylic gel-based macroporous particles Acetonitrile-water-240 mM ammonium formate buffer, pH 3 (55 40 5) (also gradient elution) 350 mm x 100 pm i.d. 250 mm active length, laser induced fluorescence detection or coupling with electrospray-ion-trap mass spectrometry... 

A combination of IPC and inductively coupled plasma (ICP) MS was extensively explored for the speciation of phosphorus, arsenic, selenium, cadmium, mercury, and chromium compounds [108-118] because it provides specific and sensitive element detection. Selenium IPC speciation was joined to atomic fluorescent spectrometry via an interface in which all selenium species were reduced by thiourea before conventional hydride generation [119], Coupling IPC separation of monomethyl and mercuric Hg in biotic samples by formation of their thiourea complexes with cold vapor generation and atomic fluorescence detection was successfully validated [120]. The coupling of IPC with atomic absorption spectrometry was also used for online speciation of Cr(III) and Cr(VI) [121] and arsenic compounds employing hydride generation [122]. 

IPC separation of monomethyl and mercuric Hg in biotic samples by formation of their thiourea complexes, coupled to cold vapor generation and atomic fluorescence detection, was successfully validated [18]. The coupling of IPC with atomic absorption spectrometry was also used for online speciation of arsenic compounds employing hydride generation [17]. In the analytical speciation of chromium using in... 

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