Comparative quantification of phosphatidylcholine in sea urchins eggs by instrumental TLC with various detection techniques

The aim of work was comparison of two detection methods of TLC plates for quantification of phosphatidylcholine (PC) in sea urchins eggs. Lyophilized sea urchins eggs from Barents Sea were used. Lipids fraction was extracted with chloroform/methanol (2/1) by sonification in 30min. A samples were spotted on Silica gel 60 F 254s glass plates (Merck, Germany) using a Linomat V system (Camag, Switzerland). The plates were developed in mixture of chloroform/methanol/acetic acid/water (7/2/0.8/0.5) [1]. PC was quantified by direct densitometric scanning of the developed plate at 202nm and after derivatization with 2% phosphomolybdic acid solution at 700nm using a Camag TLC Scanner 3. The best separation of PC, sterols, fatty acids and triglycerides was obtained. Characteristics of various techniques of PC quantification are resulted in Table 1. The quantitative results of both detection methods did not show any statistically significant differences between each other.

Table 1: Characteristics of various techniques of PC quantification

*Y – spot area in AU; X – amount of analyte in spot in µg
Parameter	Detection at 202nm	Detection at 700nm after derivatization
Regression equation*	Y=522.4+571.7X	Y=382.1+1763.8X
r	0.9992	0.9997
sdv,%	2.14	1.01
Linearity, µg/spot	2.0–10.0	2.0–5.5
LOD/LOQ, µg/spot	0.45/1.36	0.13/0.40

Thus, for PC quantification in sea urchins eggs can be used both the standard approach with plate derivatization and direct detection at 202nm.

References: 1. Essig, S., Kovar, K.A. (2001)J AOAC Int. 84(4): 1283–1286.