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Erlich reagent

The only report of the presence of a steroidal saponin is proved by Khafegi et al. [166] from the alcoholic extract of A. alexandrinus. Two saponins, a glucoside of the (22)-fiirostene type (I) and its isomer pseudosapogenin (II) have been isolated. Fig (2). Both furnish a red colour with Erlich reagent, that characterizes these types among the plant steroids. [Pg.476]

TEC with both silica and aluminum oxide adsorbents has been used to separate and isolate tertiary PAs, sometimes with ion-pairing using lithium chloride, potassium chloride, or sodium iodide [28]. Unsaturated PAs can be detected on TLC plates after spraying with Erlich s reagent [28-30]. Calibration is obtained by comparison of spot color intensity with external reference standard alkaloids. PAs can be isolated from TLC plates by excising the PA spot or band and dissolving the alkaloids from the stationary phase with polar organic solvents. Spots on TLC plates can be scanned with instruments (densitometers) that can compare their intensity with those of standards of known concentration. By this means quantities of about 1 pg can be detected reasonably quickly. [Pg.1056]

In spectroscopic methods Erlich s reagent has been used with spectrophotometric detection to measure PAs quantitatively in wheat and flour. An alternative approach is to use aqueous methyl orange, which forms a yellow complex that is very soluble in organic solvents. Methyl orange can be released from the organic solution on treatment with strong acid, and measured with a spectrometer. These methods are not able to quantify individual PAs but allow determination of the total unsaturated PA content by construction of calibration series using the readily available standards such as monocrotaline and retrorsine. [Pg.1063]

FIGURE 26.6 Mechanism of the reaction of Erlich s reagent with indoles. [Pg.1209]


See other pages where Erlich reagent is mentioned: [Pg.459]    [Pg.208]    [Pg.151]    [Pg.1164]    [Pg.155]    [Pg.1825]    [Pg.4190]    [Pg.79]    [Pg.1092]    [Pg.625]    [Pg.5]   
See also in sourсe #XX -- [ Pg.295 , Pg.296 ]




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