Monitoring Seasonal Dynamics of Broadleaf Tree Pigments with a Newly Developed High Pressure Liquid Chromatography Method

Author(s):  
F. Petibon ◽  
M.W.I. Schmidt ◽  
G.L.B. Wiesenberg
2006 ◽  
Vol 69 (11) ◽  
pp. 2712-2719 ◽  
Author(s):  
VINCENZO LIPPOLIS ◽  
MICHELANGELO PASCALE ◽  
ANGELO VISCONTI

A fluorescence polarization immunoassay previously described for deoxynivalenol (DON) screening in wheat was optimized for the rapid quantification of DON in durum wheat kernels, semolina, and pasta. A background signal was observed in both spiked and naturally contaminated samples, strictly depending on the testing matrix. After subtracting the background DON level for durum wheat (0.27 μg of DON per g), semolina (0.08 μg of DON per g), and pasta (0.04 μg of DON per g), an accurate quantification of DON was possible at levels greater than 0.10 μg/g for all matrices. Average recoveries from spiked samples (0.25 to 1.75 μg/g) were 98, 102, and 101% for wheat, semolina, and pasta, respectively. Comparative analyses of 35 naturally contaminated durum wheat samples, 22 semolina samples, and 26 pasta samples performed by both the fluorescence polarization method and high-pressure liquid chromatography/immunoaffinity cleanup showed a good correlation (r > 0.995). The fluorescence polarization method showed better accuracy and precision with respect to the high-pressure liquid chromatography method and is suitable for the rapid and quantitative determination of DON in durum wheat–based products at levels foreseen by existing or coming international regulations.


1984 ◽  
Vol 217 (3) ◽  
pp. 805-811 ◽  
Author(s):  
P N Garrison ◽  
L D Barnes

A5′pppp5′A has been proposed to serve as a molecular signal that triggers DNA replication. When published methods proved to be inadequate for the assay of A5′pppp5′A in Physarum polycephalum by h.p.l.c. (high-pressure liquid chromatography), a set of purification procedures was developed that allowed assay of as little as 2pmol of A5′pppp5′A. A5′pppp5′A was purified from cellular extract by covalent boronate chromatography, treated with alkaline phosphatase to hydrolyse residual mononucleotides and analysed by isocratic ion-exchange h.p.l.c. The analysis was facilitated by a pre-column switching procedure that allowed early-eluted species to be diverted from the analytical column. By using this procedure A5′pppp5′A has been detected in Physarum polycephalum (1.4 pmol/mg of protein), Saccharomyces cerevisiae (3.6 pmol/mg of protein) and rat liver (3.3 pmol/mg of protein). In each case a minor peak was also seen, which was identified as A5′pppp5′G. The identity of both peaks was confirmed by co-elution with standards on isocratic and gradient h.p.l.c. and treatment with enzymes, including a dinucleoside polyphosphate pyrophosphohydrolase from Physarum polycephalum.


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