Pulsed-flame photometric detector PFPD

The detection limits of a pulsed flame photometric detector (PFPD) are much better than those of any conventional FPD, and in addition the detector does not suffer the quenching of co-eluting hydrocarbon chemicals (45). The ability to also detect arsenic or nitrogen containing chemicals makes the PFPD very useful for the screening of CWC-chemicals. Frishman and Amiraw (46) used fast GC equipped with a short capillary column (1.5 m) and PFPD for the analysis of air samples. A complete analysis cycle time of 30 s was demonstrated. Killelea and Aldstadt (47) used PFPD in the arsenic selective mode for the analysis of organoarsenic chemicals. 

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 ... 

In a pulsed flame photometric detector (PFPD), the combustion of hydrocarbon molecules is fast and irreversible, and heteroatom species such as S2, HPO, and HNO emit light after the flame is extinguished and thus under cooler temperatures. Consequently, their respective emissions can be electronically gated and separated from the hydrocarbon emission. Thus, PFPD can provide selectivity against hydrocarbon interference during detection analysis. PFPD sensitivity was reported to be superior to FPD. Moreover, N and As could be also detected. The PFPD is currently available for use in benchtop instruments, such as the MINICAMS from O. I. Analytical and other GC detector manufacturers. 

FIGURE 10.8 Combustor and wall gas pathways in PFPD. (From Operator s Manual Model 5380 Pulsed Flame Photometric Detector, OI Analytical, Texas, 1997.)... 

SCD, sulfur chemiluminescence detector PFPD, pulsed flame photometric detector FPD, flame photometric detector. 

AES, atomic emission spectrometry AP(C)I, atmospheric pressure (chemical) ionization CGC, capillary gas chromatography DAD, diode array detection ESI, electrospray ionization FI, fluorescence detection ICP, indcutively coupled plasma LIE, laser-induced fluorescence Nl, negative ion NMR, nuclear magnetic resonance PFPD, pulsed flame photometric detector SRM, selected reaction monitoring. 

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. 

---