Reversed-phase high-pressure liquid chromatograms

Figure 5.7 Reversed-phase high-pressure liquid chromatogram of phenacyl ester derivatives of the fatty acids from cottonseed cotyledons and embryos. CIS (50 nun x 4.5 nun, 3 pm particle size) and C8 (150 nun x 4.5 nun, 5 pm) were used in tandem. The mobile phase was composed of acetonitrile and water, and the flow rate was 1.5 ml min . An initial mixture of acetonitrile/ water (80 20 vol./vol.) was maintained for 25 min, followed by a gradient to acetonitrile/water (85 15) for a further 10 min and then to 100% acetonitrile for a final 10 min. A variable-wavelength detector was employed. Redrawn from Wood, R., Comparison of the cyclopropene fatty acid content of cottonseed varieties, glanded and glandless seeds, and various seed structures, Biochem. Arch., 2, 73-80, 1986.

Figure 8. Reverse phase high pressure liquid chromatogram of aflatoxin (AFB- ) and its N-acetyl-cysteine derivative (NAC-AFB ). Actual elution times in minutes are shown near each peak. Att = attenuation (Friedman et al., 1982d).

Reverse phase high pressure liquid chromatography (HPLC) was used to further fractionate the sample and add another dimension of specificity (8,21). The extract was evaported to dryness and taken up in CHCI3. The entire extract was injected onto a DuPont Zorbax ODS column at 40°C using 2 cc/min. CH3OH mobile phase. Typical chromatograms are shown in Figure 2. 

Fig. 2.4. Chromatogram of a solution containing arsenite, arsenate, methylarsonic acid, dimethylarsinic acid, phenylarsonic acid, selenite, and phosphate recorded with an ARL 34000 simultaneous inductively coupled argon plasma emission spectrometer as the multi-element-specific detector [Hamilton PRP-1 resin-based reverse-phase column, Waters Associates Inc. Model 6000A high pressure liquid chromatograph, 0.1 ml injected flow rate 1.5 ml min", mobile phases 0.002 M aqueous HTAB at pH 9.6 to 250 sec, 99/1 (v/v) H2O/CH3COOH 250-1100 sec, 90/10 (v/v) H20/dimethylformamide 1100-1700 sec. ICP As 189.0 nm, P 241.9 nm, Se 203.9 nm, integration time 5 sec]. Redrawn from Spectrochimica Acta [11] by permission of Pergamon Press and the authors.

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