Detector flow-through

Ki, the detector response factor, describes the signal generated when particles are present in the eluant as it transits the detector flow-through cell. Detector response arises primarily from scattering of light by the latex particles (15), although a small contribution from light absorption by the sample may occur (16). Polystyrene latex standards of known size and concentration were used to determine Ki factors for conversion of detector response into mass concentration information. 

MSFIA-CL manifold for the determination of trace levels of orthophosphate in waters. Detector chemiluminescence detector (flow-through solid-phase optical sensor-i- photosensor module) HC holding coil PMT photomultiplier RC reaction coil V solenoid valve. 

Because of the importance of this module a really vast amount of research and development time and energy has been spent on trying to develop an ideal universal detector—flow-through cell combination. The specifications for such an analyte detector module are as follows. 

The method is based on the international standard ISO 4053/IV. A small amount of the radioactive tracer is injected instantaneously into the flare gas flow through e.g. a valve, representing the only physical interference with the process. Radiation detectors are mounted outside the pipe and the variation of tracer concentration with time is recorded as the tracer moves with the gas stream and passes by the detectors. A control, supply and data registration unit including PC is used for on site data treatment... 

Two common detectors, which also are independent instruments, are Fourier transform infrared spectrophotometers (FT-IR) and mass spectrometers (MS). In GC-FT-IR, effluent from the column flows through an optical cell constructed... 

Oil Contamination of Helium Gas. For more than 20 years, helium gas has been used in a variety of nuclear experiments to collect, carry, and concentrate fission-recoil fragments and other nuclear reaction products. Reaction products, often isotropically distributed, come to rest in helium at atmospheric concentration by coUisional energy exchange. The helium is then allowed to flow through a capillary and then through a pinhole into a much higher vacuum. The helium thus collects, carries, and concentrates products that are much heavier than itself, electrically charged or neutral, onto a detector... 

By far the most used detector is the thermal conductivity detector (TCD). Detectors like the TCD are called bulk-property detectors, in that the response is to a property of the overall material flowing through the detector, in this case the thermal conductivity of the stream, which includes the carrier gas (mobile phase) and any material that may be traveling with it. The principle behind a TCD is that a hot body loses heat at a rate that depends on the... 

In the chemiluminescence-based HPLC detection system, illustrated schematically in Figure 6, the oxalate ester and hydrogen peroxide are introduced to the eluent stream at postcolumn mixer Mj, which then flows through a conventional fluorescence detector with the exciting lamp turned off or a specially built chemiluminescence detector. The two reagents are combined at mixer Mj, rather than being premixed, to prevent the slow hydrolytic reactions of the oxalate ester. 

Flow through electrochemical detectors based on a cylindrical geometry, as opposed to a planar geometry, have also been developed Three cell designs using cy-... 

Figure 3.13 Cell designs for the thenael conductivity detector. A, flow-through cell B, semi-diffusion cell C, diffusion cell. (Reproduced with permission from ref. 163. Copyright Preston Publications, Inc.)...

In its original form the ion chromatograph used two ion-exchange columns in series followed by a flow-through conductivity detector. The first column, the separator column, separates the ions in the injected sample while the second column, the... 

Fig. 2.6.9 Visualization of gas flow through a cylindrical surface represents the rock, (b) Only porous sandstone rock. A 3D phase encoding a slice through the center of the rock is sequence with a hard encoding pulse was used, displayed, showing the origin of the gas that is (a) 3D representation of an isochronal surface flowing through the detector at different times at different times after the encoding step. The after the tagging [figure taken from 43].

The major attribute that distinguishes planar techniques from column chromatography is that in the former separation and detection are discontinuous ( offline )- In column chromatography analytes are carried through the entire column and monitored at the end, usually by flow-through detectors measuring changes in some physical characteristics of the effluent (optical... 

FTIR instrumentation is mature. A typical routine mid-IR spectrometer has KBr optics, best resolution of around 1cm-1, and a room temperature DTGS detector. Noise levels below 0.1 % T peak-to-peak can be achieved in a few seconds. The sample compartment will accommodate a variety of sampling accessories such as those for ATR (attenuated total reflection) and diffuse reflection. At present, IR spectra can be obtained with fast and very fast FTIR interferometers with microscopes, in reflection and microreflection, in diffusion, at very low or very high temperatures, in dilute solutions, etc. Hyphenated IR techniques such as PyFTIR, TG-FTIR, GC-FTIR, HPLC-FTIR and SEC-FTIR (Chapter 7) can simplify many problems and streamline the selection process by doing multiple analyses with one sampling. Solvent absorbance limits flow-through IR spectroscopy cells so as to make them impractical for polymer analysis. Advanced FTIR... 

---