HPLC of prostaglandins

A typical chromatogram produced in a normal phase separation is shown in Fig. 11.5.1. where a gradient separation was used with an initial mobile phase of chloroform and a final mobile phase of chloroform-methanol-acetic acid (93.4 6 0.6). This chromatogram demonstrates the major limitations associated with normal phase HPLC of prostaglandins where co-chromatography is often a problem 

Reversed phase is the most popular chromatographic mode used for the separation of prostaglandins. The most commonly used stationary and mobile phases are ODS in combination with a mobile 

Retention in argentation chromatography is thought to occur by two separate but simultaneous mechanisms firstly through interac- 

The most popular mobile phases used in argentation HPLC have been mixtures of chloroform (80-90%) and acetic acid 0.5%) with varying proportions of acetonitrile and/or methanol to optimally adjust chromatographic retention. Addition of methanol to the mobile phase is thought to reduce interactions with polar groups on the stationary phase (Powell, 1982) while acetonitrile reduces retention by direct interaction with silver ions bound to the stationary phase, thereby reducing interactions with the olefinic unsaturated bonds (Merritt and Bronson, 1977). Adjustment of the composition of the mobile phase allows the specific types of interactions between the mobile phase, sample molecules and stationary phase to be enhanced or reduced in this way an optimal chromatographic separation can be achieved. 

In summary, argentation HPLC provides a useful alternative to conventional reversed phase chromatography for the isolation and quantitation of prostaglandins. The major advantages of this technique are that it provides a better resolution of compounds which 

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