Model 660 HPLC Chemiluminescence Detector
Perform highly sensitive (picomolar) HPLC detection and rapid clinical analysis of chemiluminescence assays with the McPherson modular chemiluminescence (CL) detector. Use your existing HPLC pumps, plumbing and your PC or Mac computer in conjunction with the new McPherson detection system.
Offering a novel detection head, high resolution A/D converter and computer control, McPherson recommends this detector for users of UV-VIS or fluorescence detectors that require greatly improved detection limits. Featuring a unique spiral flow cell design which places the mixing point directly in front of the highly sensitive detector, this system detects the fastest and least energetic events - it is the most sensitive even in relation to other CL detectors - since reactions take place directly in front of the detector.
Chemiluminescence reactions start as soon as samples are mixed. The CL reaction then quickly reaches a maximum and begins to decay. Other detectors lose valuable signal while reagents are still in mixing T's in our unit! The CL signal is directly collected by the photomultiplier tube, is amplified and processed via a high resolution A/D board, data is acquired and analyzed by PC software.
McPherson is pleased to offer both the modular detection head and also options for complete turnkey systems. User friendly total systems include, high pressure pumps, syringe pumps, injectors, columns, plumbing, efficient mixing T's, etc. The component clusters contain everything required to get your analysis on line and operational.
Chemiluminescent emission is due to an exothermic reaction causing a strong fluorophore, to be excited. Chemi-exicitation needs favorable reaction pathways to form a luminescing species. The excited product can relax by releasing a light photon or heat. Common reagents used in chemiluiminescence systems include luminol, lucigenen and lophine while common oxidants are hydrogen peroxide, hypochlorite ion and ferricyanide. A common catalyst, imidazole.
Luminescence from chemi-excitation occurs in the same time frame as photo-excitation. There is a finite time for the mixing of reagents and maximum chemiluminescence to occur. The signal then decays as the reagents become exhausted.
Quantum efficiency for chemiluminescent reactions is related to
the product of two efficiencies; the fraction of molecules that
produce an excited molecule and the luminescent efficiency.
Successful application of chemiluminescence methods requires a detector, such as the McPherson Model 660, which:
Compared to photoluminescence there is no scattering or background luminescence signal to interfere with data acquisition. Thus, limitations of conventional detectors are avoided and detection limits are much improved.
Light sources and discreet wavelength selection is not required resulting in simple to operate and low maintenance instrumentation. Many scientists are developing new chemiluminescence applications. Chemiluminescence compounds are currently being synthesized which upon reaction with enzymes can produce photons (light) at room temperature!
While it is impossible to replace fluorescence as an extremely accurate, sensitive and accepted means of detection - some applications benefit from the higher sensitivity obtained with chemiluminescence methods.
For instance, a popular HPLC fluorescence method utilizes peroxy oxalate (PO). If PO is reacted with hydrogen peroxide in the presence of a suitable fluorophore (as dansylated amines) photons will be produced. Utilizing chemiluuminescence methods, in contrast to fluorescence, much higher sensitivity is achieved in the detection of dansyl amino acids. The main reason for this is the simplicity of the chemiluminescence detector. No light source is required and thereby the main contributor of scatter and subsequently background noise is eliminated.
The Model 660 detector is the least expensive method of adding chemiluminescent capabilities to your laboratories analytical tools. Researchers currently using one of the popular McPherson 749/750 style fluorescence detectors can expand to include chemiluminescence detection just by adding the Model 660 detector. Electronics in the fluorometer series permit read out of data with existing equipment (integrators, A/D boards, etc.).