Solvent segmentation in liquid chromatography —application to photochemical reactions detectors

Gas-nebulized direct liquid introduction interface for liquid chromatography/mass spectrometry

“…Clobazam, a tranquilizer, and its major metabolite desmethylclobazam are two polar compounds that we have previously analyzed by LC with photochemical reaction detection (14). The polarity of these compounds coupled with their thermal lability and biological matrices makes them problematic for GC analysis.…”

Comparison of liquid segmented with nonsegmented flow systems in post-column reactors for liquid chromatography

“…In the present paper it has been demonstrated that with appropriately designed phase separators (and tee pieces) segmented-flow systems can become highly competitive with nonsegmented systems as postcolumn reactors even for short-i.e., less than 0.5-1 min-reaction times. The reported results, admittedly, relate to solvent-segmented systems only; it has experimentally been verified, however, that the various conclusions also hold true in the case of air segmentation (14,20).…”

“…Calculation yielded rather similar results of 150 ± 20 µ 2 (eq 5) and 130 /uL2 (eq 7). The calculated variance for the reactor, 2 0 0 , is solely due to the phase separator and/or tee piece, since it has previously been demonstrated (14) that no noticeable band broadening occurs in the reaction capillaries if segmentation is used. This implies that the band broadening contribution of the phase separator is rather low compared to earlier observations of 7000-9000 µ ß reported for an air-segmentation system (4).…”

“…cr2Vireactor can be replaced by oMhase-sepi38 has been shown in the previous section. tf2V|Seg can then be expressed as 2 5 24Dm 2 + 2 v,phase-sep (12) If, for convenience, the term T¡rt4Lt/24£>m is written as kt and Mphaae-sep 38 &2> e9 12 can be written as 22 Vi2 <r2v,aeg = ~~2~ + M2 + k2 (13) 0 where h is the peak height and the band broadening, eq 8 can be written as Likewise, for the nonsegmented system, in which the injection valve is coupled to the detector via the connective capillary, the variance according to eq 6, can be written as V¡2 <r2v,n-seg = + Ml (14) The variances shown on the right-hand side of this equation are given by eq 5 and 6, respectively, and haeg and hn.aeg are the height of the peaks recorded in a segmented and nonsegmented system, respectively.…”

Simultaneous monitoring of both phases in the solvent extraction/flow injection analysis of Dramamine tablets

“…traction/FIA has been used in postcolumn detection systems for liquid chromatography (3)(4)(5), for sample preconcentration prior to atomic absorption spectrometry (6,7), and for multiple extraction (8,9). A major development in extraction/FIA has been the use of porous membrane phase separators.…”