Ajg. Mank et al., COLUMN LIQUID-CHROMATOGRAPHY WITH DIODE LASER-INDUCED FLUORESCENCE DETECTION OF CARBOXYLIC-ACIDS AFTER PRECOLUMN DERIVATIZATION, Analytica chimica acta, 315(1-2), 1995, pp. 209-216
Several pre-column approaches to fluorescence derivatisation of carbox
ylic acids, compatible with diode laser-induced fluorescence (DIO-LIF)
detection, were compared. For this purpose red-absorbing labels conta
ining hydrazide, bromoacetamide and iodoacetamide functionalities were
studied. The sensitivity of DIO-LIF detection is illustrated by the (
3-10) X 10-(12) M (75-250 amol) detection limit for various derivatise
d carboxylic acids. The real-life detection limit for the carboxylic a
cids is 3 x 10(-8) M, because derivatisation is not quantitative at lo
wer concentrations. Derivatised n-alkylcarboxylic acids and non-steroi
dal anti-inflammatory drugs are easily separated by column liquid chro
matography, despite the attachment of the bulky red-absorbing labels.
The determination of the anti-inflammatory drug naproxen in saliva is
shown as an example.