|Tumlinson Iii, James|
Submitted to: Analytical Biochemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/8/2002
Publication Date: 1/15/2003
Citation: Engelberth, J.E., Schmelz, E.A., Alborn, H.T., Cardoza, Y.J., Huang, J., Engelbert, J.E., Schmelz, E.A., Alborn, H.T., Cardoza, Y.J., Huang, J., and Tumlinson III, J.H. 2003. Simultaneous quantification of jasmonic acid and salicylic acid in plants by vapor phase extraction and gas chromatography-chemical ionization-mass spectrometry. 313:212-250. Analytical Biochemistry. Interpretive Summary: The regulation of defense responses in plants after insect or pathogen attack is supposed to be regulated mainly by two compounds, Jasmonic acid and Salicylic acid. To get further insights into the mechanisms of the plant responses it is necessary to determine how much of these two important signaling compounds are produced. Scientists at the Center for Medical, Agricultural and Veterinary Entomology, USDA-ARS Gainesville, Florida have developed a new chemical method to quantify these compounds. The new method makes it possible to quantify both signaling compounds from small amounts of plant material with high efficiency. Sample preparation is reduced to one purification step based on volatilization of the appropriate compound and collection on a convenient filter material and subsequent chemical analysis. The method reduces the amount of solvents dramatically, is easy to handle and facilitates the quantification of more than 50 samples routinely per day.
Technical Abstract: Jasmonic acid and salicylic acid represent important signaling compounds in plant defensive responses against other organisms. Here, we present a new method for the easy, sensitive and reproducible quantification of both compounds by vapor phase extraction and gas chromatography-positive ion chemical ionization-mass spectrometry. The method is based on a one-step extraction, phase partitioning, methylation with HCl/Methanol, and collection of methylated and thus, volatilized compounds on Super Q filters, thereby omitting further purification steps. Eluted samples are analyzed and quantified by GC/MS with chemical ionization. Standard curves were linear over a range of 5 to 1000 ng for jasmonic acid and salicylic acid. The correlation coefficients were greater than 0.999 and the recovery rates estimated between 70-90% for salicylic acid and 90-100% for jasmonic acid. The limit of detection was about 500 fg by using single ion detection mode. Both, cis- and trans-isomers for jasmonic acid can be detected. A comparison with established methods indicates the new method to be highly efficient, allowing reliable quantification of both compounds from small amounts of plant material (5 mg to 400 mg).