Sulfur-phosphorus flame photometric detectors

Selective to sulfur and phosphorus compounds more selective than NPD to compounds containing phosphorus Flame photometric detector Organophosphorus pesticides (EPA 8141) Sulfur compounds may interfere with organophosphorus pesticides. 

Because one of the end groups in most of the PMMA examined in this study should have a sulfur atom or a cyano group, the Py-GC system is equipped with a simultaneous multidetection system. A FID was always used in conjunction with a sulfur-selective flame photometric detector (FPD) or a nitrogen-phosphorus detector (NPD). 

Other Detectors Two additional detectors are similar in design to a flame ionization detector. In the flame photometric detector optical emission from phosphorus and sulfur provides a detector selective for compounds containing these elements. The thermionic detector responds to compounds containing nitrogen or phosphorus. 

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. 

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. 

The flame photometric detector, which is sensitive to sulfur or phosphorus, shows diminished response to sulfur compounds, if large amounts of hydrocarbons are eluted simultaneously. This happens even though there is no significant response on the chromatogram from the interfering hydrocarbons. The opposite effect can also occur. In some of the newer types of electron... 

The impact of the flame photometric detector (FPD) resides in its simultaneous sensitivity and specificity for the determination of sulfur and phosphorus. It is inherently compatible with the FID and as such affords the analytical chemist a discriminating ability beneficial to many analyses. In 1966, Brody and Chaney published data on their design of an FPD (26)(Figure 5.18). 

Flame photometric detector (FPD) selective to compounds containing sulfur and phosphorus... 

Gas chromatography (GC) analysis with element-specific detectors, for example, a nitrogen-phosphorus detector (NPD), a flame photometric detector (FPD, in sulfur or phosporus mode) and/or an atomic emission detector (AED) ... 

The FPD is based on a German patent describing the emission obtained with phosphorus and sulfur compounds in a hydrogen-rich flame (64). Brody and Chaney developed this analytical method into a detector for gas chromatographic eflSuents (65) and predicted (correctly) its development in the years to come. Today, Tracor, Inc., markets it as Melpar flame photometric detector in single- and double-channel versions. 

The flame photometric detector possesses a few characteristics which predestine it for residue analysis. As shown mainly by the group of Bowman, Beroza, and coworkers (67, with literature references), it discriminates against compounds devoid of phosphorus or sulfur by factors in the range of four to five orders of magnitude and can therefore be used for samples with little history of purification. 

Some techniques may offer selective screening as well as specificity —e.g., microcoulometric methods described by Coulson et al. (24). This technique consists of a combination of gas chromatography, combustion, and continuous coulometric titration for chlorine or sulfur. The development of the flame photometric detector offers a similar potential for the selective screening and specificity of pesticides which contain phosphorus or sulfur (25). Even so, one or more tests in addition to the initial... 

In trace analysis of contaminant substances, one can use specific detectors for certain compounds, such as a nitrogen-phosphorus detector (NPD), thus gaining detection ability for nitrogenated and phosphorylated compounds the electron-capture detector (ECD) shows excellent performance for chlorinated substances and the flame photometric detector (FPD) is the most widely used for sulfur-containing compounds. 

Gas chromatography with either sulfur chemiluminescence detection or atomic emission detection has been used for sulfur-selective detection. Selective sulfur and nitrogen gas chromatographic detectors, exemplified by the flame photometric detector (FPD) and the nitrogen-phosphorus detector (NPD), have been available for many years. However, these detectors have limited selectivity for the element over carbon, exhibit nonuniform response, and have other problems that limit their usefulness. 

When sulfur and phosphorus compounds are burned in an FDD-type flame, chemiluminescent species are produced that produce light at 393 nm (sulfur) and 526 nm (phosphorous). An optical interference filter passes the appropriate light to a photomultiplier tube, a sensitive photon detector. These detectors are known as flame photometric detectors (FPD).. ... 

Pollutants in Water Via Simultaneous Gas Chromatography Employing Flame Ionization and Flame Photometric Detectors for Sulfur and Phosphorus, Proceedings 13th Conference, International Association Great Lakes Research, 1970 pp. 128-136. 

In the early 1990s Amirav et al. introduced a new strategy for the operation of FPD based on a pulsed flame instead of a continuous flame for the generation of flame chemiluminescence. This pulsed flame photometric detector (PFPD) is characterized by the additional dimension of a light emission time and the ability to separate in time the emission of sulfur species from those of carbon and phosphorus, resulting in considerable enhancement of detection selectivity. In addition, detection sensitivity is markedly improved, thanks to ... 

GC is the most commonly used technique. It has, thanks to capillary columns, a very good resolution and enables, when coupled with other specific detectors such as the electron capture detector (BCD), nitrogen phosphorus detector (NPD), flame photometric detector (FPD), pulsed flame photometer (PFPD) and AED separation, identification, and quantification of OPPs containing halogenated groups, or phosphorus or sulfur atoms. 

The response of the flame photometric detector is due to chemiluminescence subsequent to combustion of certain organic molecules in an energetic flame. The initial work on this principle by Brody and Chaney [109] was primarily concerned with selective detection of sulfur and phosphorus compounds, although detection of other elements is also feasible with different optical filters. 

The use of the flame photometric detector in the sulfur-sensitive mode (attributed to the emission of S2 spectral species at 394 nm) is exemplified in measuring the sulfur-containing volatiles in physiological fluids [110], or breath of liver-disease patients [111]. A word of caution concerns the fact that co-eluting non-sulfur compounds may result in a diminished or quenched response of the measured species [112]. Hence, the need for maximum solute separation. The detector is responsive to nanogram amounts of sulfur-containing compounds, but the response increases with the square of sulfur content [112]. Merits of the flame photometric detector in the detection of phosphorus compounds is somewhat overshadowed by a similar capability of the thermionic detector. 

The flame photometric detector (1 PD) has been widely applied to the analysis of air and water pollutants, pesticides, and coal hydrogenation products. It is a scTeciivc detector that is primarily rc.sponsivc to compounds containing sulfur and phosphorus. In this detector, the eluent is passed into a low-temperature hydrogen-air flame, which converts part of the phos-phoru to an UK) species that emits bands of radiation centered at about 510 and 526 nm. Sulfur in the... 

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