Cochineal (Dactylopius coccus) LC

dried cochineal insects photo by X. Zhang

Description

The cochineal is a scale insect in the suborder Sternorrhyncha, from which the natural dye carmine is derived. Cochineal lives on catcti in the genus Opuntia. Cochineal is native to tropical and subtropical South America as well as Mexico and Arizona. These insects are brushed off and dried for storage.

The insect produces carminic acid that deters predation by other insects. Carminic acid, typically 17-24% of dried insects' weight, can be extracted, then mixed with aluminium or calcium salts to make carmine dye.

Analytical instrumentation and procedures

HPLC-DAD-MS analysis was performed with an Agilent 1100 liquid chromatography system consisting of an automatic injector, a gradient pump, a HP series 1100 DAD, and an Agilent series 1100 VL on-line atmospheric pressure ionization electrospray ionization mass spectrometer. Separations were done on a Vydac 214TP52 analytical column (2.1 mm diameterX250 mm; 5-ím particle size). The column was eluted at a flow rate of 0.2 mL/min with a tertiary gradient of water (A),acetonitrile (B), and 1% (v/v) aqueous formic acid (C) with the following elution program: 0 min, 90% A, 5% B, 5% C; 0-55 min, a linear gradient to 35% A, 60% B, 5% C; 55-60 min, a linear gradient elution to 15% A, 80% B, 5% C; 60-62 min, isocratic elution at 15% A, 80% B, 5% C; 62-70 min gradient elution to 90% A, 5% B, 5% C; and reequilibration with the latter solvent for 15 min. The mass spectrometer was run both in the negative and positive ion mode.

Chromatograms

Absorbance at 350nm (mAU)

Sample information

File:.JPG

sample information, By R. A. Laursen, Boston University

Identified compounds

Carminic acid UV

Compound	RT (min.)	MW	UV/vis	Other
carminic acid	xx0	xx	xx	Comments here
x	x	x	x
x	x	x	x
x	x	x	x

References

[1] [2] [3]