Resumo: To identify lhe nitrogen transportation forms and attain the control mechanism, the amount of free amino acids in different parts of lhe plant has to be determined. An automatic, fast and reliable procedure multicomutated flow system {1] has been developed for spectrophotometric analysis of totalamino acids in plant material. The method is suitable for routine analysis for a large number of samples of plant material. The flow manifold was designed with computer-controlled three-way solenoid valves for independent handling of sample and reagent solutions and a data acquisition system from a spectrophotometer, employed for signal measurements. The software for system control was performed bya program with use of a LabView platform INationallntruments) [2]. The detection reaction was based on the complexation of amino functional groups of amino acids by ninhydrin. It reacts with free a-amino groups, producing lhe colored ninhydrin chromophore called Ruhemann's purple IRP) IAm". = 570 nm; E = 22 000) [3]. The proposed detection system shows a linear range concentration up to 2.0 X 10-3 mal L-I with coefficient of variation of 1.1% (n = 101. Detection limits were estimated as 2.8 x 10-3 mal L-I at 99.7% confidence level for total amino acids. and a mean sampling rale of 30 determinations per hour was achieved.

Ano de publicação: 2006

Tipo de publicação: Resumo em anais e proceedings

Unidade: Embrapa Pecuária Sudeste