Comparison of a pulsed electron capture detector and a Fourier transform ion mobility detector after capillary supercritical fluid chromatography

Supercritical Fluid Chromatography and Extraction

“…Electronic compensation was used to eliminate the drift. This same baseline rise of the ECD with flow rate was observed by Tarver and Hill, as discussed below (170). Moulder et al evaluated the use of the ECD in SFC using agrochemicals as probe analytes (171).…”

Ion Mobility Spectrometry: Arriving on Site and Moving beyond a Low Profile

“…noyance to nearly a nonstarter owing to the regulatory climate for beta sources. Initial permits, regular veri®cation of source leakage, and limitations on transportation, now brought to full implementation, make 63 Ni im-practical. Fortunately, several promising alternatives have been described.…”

“…One leading alternative source to 63 Ni that has been demonstrated is a point-to-point corona in which thin ® bers are used to create reactant ions via a pulsed discharge of low current. This source has proven electrical and physical behavior, and the ch em istr y m u st b e pro ven.…”

“…The drawing in Fig. 2 (top frame) shows a b emitter (norm ally 63 Ni) in the ion source region, and 63 Ni remains to-day the m ost widely used ion source, despite growing dif® culties in obtaining and using such sources with portable analyzers. The processes of ion form ation follow atmospheric pressure chemical ionization (APCI) reactions; APCI sources as embodied in IMS analyzers have advantages such as high selectivity and excellent detection limits and dif® culties such as the effects of clusterization and competitive charge exchange reactions (vide infra).…”

“…Q uantitative response in IMS is often more than 90 ±95% reproducible in the region of nanogram s to m icrograms, though the linear range is often limited (see Fig. 7) and is som etimes only 2 orders of magnitude with 63 Ni ion sources. However, working ranges with photodischarge lamps can be 5 orders of magnitude.…”