Separation of paralytic shellfish poisoning toxins on Chromarods-SIII by thin-layer chromatography with the Iatroscan (mark 5) and flame thermionic detection

Thin-layer chromatography (TLC) on Chromarods-SIII with the Iatroscan (Mark -5) and a flame thermionic detector (FTID) was used to develop a rapid meth od for the detection of paralytic shellfish poisoning (PSP) toxins. The eff ect of variation in hydrogen (H-2) flow, air flow, scan time and detector c urrent on the FTID peak response for both phosphatidylcholine (PC) and PSP were studied in order to define optimum detection conditions. A combination of hydrogen and air flow-rates of 50 ml/min and 1.5-2.0 1/min respectively , along with a scan time of 40 s/rod and detector current of 3.0 A (ampere) or above were found to yield the best results for the detection of PSP com pounds. Increasing the detector current level to as high as 3.3 A gave abou t 130 times more FTID response than did flame ionization detection (FID), f or PSP components. Quantities of standards as small as 1 ng neosaxitoxin (N EO), 5 ng saxitoxin (STX), 5 ng B1- toxins (B1), 2 ng gonyautoxin (GTX) 2/3 , 6 ng GTX 1/4 and 6 ng C-toxins (C1/C2) could be detected with the FTID. T he method detection limits for toxic shellfish tissues using the FTID were 0.4, 2.1, 0.8 and 2.5 pg per mu g tissue for GTX 2/3, STX, NEO and C toxins , respectively. The FTID response increased with increasing detector curren t and with increasing the scan time. Increasing hydrogen and air flow-rates resulted in decreasing sensitivity within defined limits. Numerous solvent systems were tested, and, solvent consisting of chloroform: methanol-water -acetic acid (30:50:8:2) could separate C toxins from GTX, which eluted ahe ad of NEO and STX, Accordingly, TLC/FTID with the Iatroscan (Mark-5) seems to be a promising, relatively inexpensive and rapid method of screening pla nt and animal tissues for PSP toxins. (C) 1999 Elsevier Science B.V. All ri ghts reserved.