Automated Flow Injection Chromatography for the Rapid Assay of Parabens in Hygiene Wipes

A new flow-injection chromatography method exploiting linear-gradient elution for fast quantitative screening of parabens in cosmetics

“…The results are summarized in Table 3. These LODs were better than those of currently used isocratic low-pressure separation methods 11,12 and similar to or better than those of existing step-gradient FIC and SIC methods. [14][15][16] 3.4.3 Recovery and precision of the method.…”

“…However, the 4 parabens normally used in cosmetic products cover a broad polarity range, from the polar MP and EP (both of which elute early in reverse-phase LC) to the medium-polarity PP and the more hydrophobic BP (which is strongly retained on C18 sorbents) and, therefore, isocratic separation of these compounds is far from efficient. [10][11][12] One option to create a mobile phase with varying polarity in SIC is the generation of a gradient prole in the holding coil of the SIC manifold by sequentially aspirating the zones of solvents of different polarities; 13 however, this method is not applicable to FIC. A simple approach to modulate the elution force of the mobile phase in low-pressure separations is the step-gradient method involving sequential elution of analytes with two or more separate solvents of different polarities.…”

Programmable Low-Pressure Chromatographic Sub-90 s Assay of Parabens in Cosmetics with Post-Column Chemiluminescence Detection

“…The simpler methods rely on isocratic elution with a mobile phase consisting of a single solvent. However, since the four parabens normally used in cosmetics differ in polarity (from the highly polar MeP to the more hydrophobic BuP), separation under isocratic conditions is time-consuming and not efficient; therefore, it has been limited to the assay of the more polar parabens [21,22]. A more efficient approach to modulate the elution force of the mobile phase is based on the sequential use of two or more solvents of decreasing polarity [23][24][25].…”