Detectors filter photometric

Twenty analytical units for Individual determination of as many analytes. In addition to independent reagent and diluent streams, heaters, dia-lysers, etc., they are provided with their own detector, usuaiiy photometric (for both end-point and kinetic determinations), and occasionally potentio-metric (ISE). In colorimetric determinations each analytical unit posseses one or several flow-cells and a suitable filter. 

Depending on the light source, the UV detector can operate from 190 nm and well into the visible area. The UV detector can be of various kinds, for example, filter photometric detectors, spectrophotometric detectors, and diode array detectors. 

Filter photometric detectors use light sources that emit light at a few distinct wavelengths. The main light source is the mercury lamp that emits light at 254, 313,... 

Unlike the filter photometric detector, which is limited to one or a few wavelengths, the spectrophotometers can choose the wavelength that is closest to an absorption maximum of the analyte(s) in order to obtain the highest sensitivity. 

For a FT-IR spectrometer to achieve perfect photometric accuracy, the response of the detector and its associated amplifiers and electronic filters must be independent of the photon flux on the detector. This condition is usually fulfilled with pyroelectric detectors but is particularly difficult to achieve in the mid-infrared with photo-conductive MCT detectors. The photometric response of MCT detectors is usually linear at very low signal levels but may be easily forced into nonlinear behavior by... 

The flame-photometric detector (FPD) is selective for organic compounds containing phosphoms and sulfur, detecting chemiluminescent species formed ia a flame from these materials. The chemiluminescence is detected through a filter by a photomultipher. The photometric response is linear ia concentration for phosphoms, but it is second order ia concentration for sulfur. The minimum detectable level for phosphoms is about 10 g/s for sulfur it is about 5 x 10 g/s. 

Photometric Moisture Analysis TTis analyzer reqiiires a light source, a filter wheel rotated by a synchronous motor, a sample cell, a detector to measure the light transmitted, and associated electronics. Water has two absorption bands in the near infrared region at 1400 and 1900 nm. This analyzer can measure moisture in liquid or gaseous samples at levels from 5 ppm up to 100 percent, depending on other chemical species in the sample. Response time is less than 1 s, and samples can be run up to 300°C and 400 psig. 

Flame Photometric Detector3 With the flame photometric detector (FPD), as with the FID, the sample effluent is burned in a hydrogen/air flame. By using optical filters to select wavelengths specific to sulfur and phosphorus and a photomultiplier tube, sulfur or phosphorus compounds can be selectively detected. 

Flame photometric detector fitted with a 394-nm sulfur-specific filter 240 °C... 

Gas chromatograph for fused-silica capillary or packed columns, equipped with a flame photometric detector (with sulfur filter), Hewlett-Packard, Carlo Erba, or equivalent... 

Addison and Ackman [69] have described a direct determination of elementary yellow phosphorus in mud in which the phosphorus is extracted with benzene or isooctane. Gas chromatographic separation is achieved on a 2mx3mm column packed with 3% OV-1 or SE-30 on Chromosorb W maintained at 100 or 120°C respectively. The carrier gas was helium (80ml m 1). A flame photometric detector with a 526nm filter at 200°C was employed. Down to lpg of phosphorus could be determined. 

The simplest types of photometric instrument are designed for measurements in the visible region of the spectrum only and rely on coloured filters and simple photoelectric detectors. The name colorimeter is often used to describe such instruments although this is not necessarily correct and the word should probably be reserved for visual comparators rather than photoelectric instalments. 

The detection performance of an LIF photometric device is governed by the emission filter(s), excitation filter(s), detector type, the excitation source and the detection scheme. The selection of optical elements and device configuration as it relates to the detection performance is further described by expanding the collection efficiency term in Equation 11.3 ... 

A flame photometric detector measures optical emission from phosphorus, sulfur, lead, tin, or other selected elements. When eluate passes through a Hrair flame, as in the flame ionization detector, excited atoms emit characteristic light. Phosphorus emission at 536 nm or sulfur emission at 394 nm can be isolated by a narrow-band interference filter and detected with a photomultiplier tube. 

Sulfur Dioxide. Both flame photometric and pulsed fluorescence methods have been applied to the continuous measurement of S02 from aircraft. In the flame photometric detector (FPD), sulfur compounds are reduced in a hydrogen-rich flame to the S2 dimer. The emission resulting from the transition of the thermally excited dimer to its ground state at 394 nm is measured by using a narrow band-pass filter and a photomultiplier tube. 

Instrument and column conditions. A Tracor 222 gas chromatograph equipped with a flame photometric detector (FPD) operating in the phosphorus mode (526 mu) filter was used. The operating conditions of the flame photometric gas chromatographic analyses were as follows ... 

Various alkyl and aryltin compounds were determined in aquatic matrices, namely sediments, biota and water by means of gas chromatographic methods. In this work, comparisons of single or dual flame photometric detectors and electron capture detectors were reported (Tolosa et al., 1991). Sample preparations included acid digestion, extraction, formation of methyl derivatives and clean-up with alumina prior to gas chromatographic analysis. With the electron capture detector, cold on-column injection of organo-tin chlorides was studied. The conclusion was that a single or dual flame photometric detector equipped with a 600 nm interference filter yielded the best performance for determinations of tin species as methyl derivatives. Detection limits for the method using flame... 

Figure 1. Vertical concentration profiles for DMS, chlorophyll a and DMSP in the western basin of the Cariaco Trench off Venezuela (10° 39 N, 65°30 W). DMS was determined by sparging and gas chromatography with a flame photometric detector. Particulate DMSP was determined bv base treatment of material collected on 0.22 pm filters and analysis of the DMS released free DMSP was determined as DMS released upon base treatment of sparged water samples obtained after initial DMS analysis. Chlorophyll a data from W. Cooper and R. Zika (personal communication).

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