Degradação luminosa e retenção foliar dos corantes azul brilhante FDC-1 e amarelo tartrasina FDC-5 utilizados como traçadores em pulverizações
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Data
2005-06-01
Autores
Marchi, S.R. [UNESP]
Martins, D. [UNESP]
Costa, N.V. [UNESP]
Terra, M.A. [UNESP]
Negrisoli, E. [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Sociedade Brasileira da Ciência das Plantas Daninhas
Resumo
Três estudos foram conduzidos no Núcleo de Pesquisas Avançadas em Matologia (NUPAM) pertencente à UNESP/FCA - campus de Botucatu-SP, com o objetivo de avaliar a estabilidade dos corantes Azul Brilhante FDC-1 e Amarelo Tartrasina FDC-5 quanto a diferentes períodos de exposição à luz solar e contato com folhas de Eichhornia crassipes. No primeiro estudo, soluções de 0,3125, 0,625, 1,25, 2,5, 5, 10 e 20 ppm dos corantes Azul Brilhante FDC-1 e Amarelo Tartrasina FDC-5 foram acondicionadas em tubos de quartzo hermeticamente fechados e submetidos a 0, 0,5, 1, 2, 4, 6 e 10 horas de exposição à luz solar e ao escuro. Ao final de cada período, amostras de 10 mL foram retiradas dos tubos e analisadas. No segundo estudo, os tratamentos foram dispostos no esquema fatorial 2x7: duas condições luminosas (escuro e pleno sol) e sete períodos de exposição (0, 0,5, 1, 2, 4, 6 e 10 horas), com seis repetições. Com o auxílio de micropipeta, oito gotas de 5 µL das soluções Azul Brilhante e Amarelo Tartrasina a 4.000 ppm foram depositadas em placas de Petri de vidro. Após o término dos períodos de exposição, as placas foram lavadas com 50 mL de água destilada, com o objetivo de extrair o corante depositado sobre elas. No terceiro estudo, adotaram-se os mesmos tratamentos do segundo experimento, com quatro repetições, porém as soluções foram depositadas sobre as folhas de plantas de Eichhornia crassipes. Foram adotados também os mesmos procedimentos de extração dos corantes após o término dos períodos de exposição. As soluções finais obtidas nos três estudos foram submetidas à leitura óptica de absorbância em espectrofotômetro UV-visível nos comprimentos de onda de 630 e 427 nm, para os corantes Azul Brilhante FDC-1 e Amarelo Tartrasina FDC-5, respectivamente. As várias concentrações das soluções de ambos os corantes não sofreram degradação pela luz solar quando submetidas aos vários períodos de incidência luminosa nos tubos de quartzo (ambiente fechado), visto que as curvas de recuperação apresentaram equações semelhantes àquelas concentrações que foram mantidas no escuro. A mesma estabilidade também foi observada quando os corantes foram submetidos à luz solar em ambiente aberto, ou seja, nas placas de Petri. O corante Amarelo Tartrasina também se apresentou muito estável quando depositado sobre as folhas de E. crassipes, independentemente da exposição ou não à luz solar. Para o corante Azul Brilhante, ocorreram significativas perdas de 7,8 e 18,6% quando esteve depositado na superfície da folha de aguapé pelo período de 10 horas sob condições de escuro e plena luz solar, respectivamente.
Three trials were carried out at Núcleo de Pesquisas Avançadas em Matologia (NUPAM), FCA/UNESP - Campus de Botucatu, SP, Brazil, to evaluate the stability of dyes FD&C Blue no. 1 and FD&C Yellow no. 5 when exposed to different periods of solar light and Eichhornia crassipes leaf contact. Solutions at 0,3125, 0,625, 1,25, 2,5, 5, 10 and 20 ppm of both dyes were prepared and conditioned into Quartz tubes hermetically closed and submitted to several solar light and darkness periods, as follows 0; 0,5; 1; 2; 4; 6 and 10 hours. Samples of 10 mL were collected from the tubes after the end of each period and left to posterior analysis. The second trial treatments were designed as a factorial 2x7: 2 light conditions (sunlight or darkness) and 7 exposure timings (0; 0,5; 1; 2; 4; 6 and 10 hours), with six replications. Eight drops of 5 µL of FD&C Blue no. 1 and FD&C Yellow no. 5 solutions at 4,000 ppm were placed on glass Petri dishes, using a micropipette. Petri dishes were washed with 50 mL of distilled water immediately after each exposure period ending to extract the dyes deposited on it. The same treatments were used in the third trial, with four replications. However, the coloring solutions were dropped on Eichhornia crassipes foliar surfaces. The same dye extraction procedures were also used after each exposure period ending. The final solutions obtained from the three trials were submitted to absorbance optical analysis at spectrophotometer UV-Visible on wave length of 630 and 427 nm for FD&C Blue no. 1 and FD&C Yellow no. 5 dyes, respectively. Both coloring solutions at different concentrations were not degraded by solar light after being submitted to each exposure period of sunlight incidence into the Quartz tubes (closed situation), since recovering curves showed practically the same equations when compared to the dye solutions kept under darkness conditions. The same stability was observed when the dye solutions were submitted to sun light incidence in open ambient, i.e., on Petri dishes. FD&C Yellow no. 5 showed high stability when dropped over E. crassipes leaves, regardless of the light condition. However, statistical losses of 7.8% and 16.8% were observed when FD&C Blue no. 1 was dropped over the surface of water hyacinth leaves during 10 h under darkness and sunlight incidence conditions, respectively.
Three trials were carried out at Núcleo de Pesquisas Avançadas em Matologia (NUPAM), FCA/UNESP - Campus de Botucatu, SP, Brazil, to evaluate the stability of dyes FD&C Blue no. 1 and FD&C Yellow no. 5 when exposed to different periods of solar light and Eichhornia crassipes leaf contact. Solutions at 0,3125, 0,625, 1,25, 2,5, 5, 10 and 20 ppm of both dyes were prepared and conditioned into Quartz tubes hermetically closed and submitted to several solar light and darkness periods, as follows 0; 0,5; 1; 2; 4; 6 and 10 hours. Samples of 10 mL were collected from the tubes after the end of each period and left to posterior analysis. The second trial treatments were designed as a factorial 2x7: 2 light conditions (sunlight or darkness) and 7 exposure timings (0; 0,5; 1; 2; 4; 6 and 10 hours), with six replications. Eight drops of 5 µL of FD&C Blue no. 1 and FD&C Yellow no. 5 solutions at 4,000 ppm were placed on glass Petri dishes, using a micropipette. Petri dishes were washed with 50 mL of distilled water immediately after each exposure period ending to extract the dyes deposited on it. The same treatments were used in the third trial, with four replications. However, the coloring solutions were dropped on Eichhornia crassipes foliar surfaces. The same dye extraction procedures were also used after each exposure period ending. The final solutions obtained from the three trials were submitted to absorbance optical analysis at spectrophotometer UV-Visible on wave length of 630 and 427 nm for FD&C Blue no. 1 and FD&C Yellow no. 5 dyes, respectively. Both coloring solutions at different concentrations were not degraded by solar light after being submitted to each exposure period of sunlight incidence into the Quartz tubes (closed situation), since recovering curves showed practically the same equations when compared to the dye solutions kept under darkness conditions. The same stability was observed when the dye solutions were submitted to sun light incidence in open ambient, i.e., on Petri dishes. FD&C Yellow no. 5 showed high stability when dropped over E. crassipes leaves, regardless of the light condition. However, statistical losses of 7.8% and 16.8% were observed when FD&C Blue no. 1 was dropped over the surface of water hyacinth leaves during 10 h under darkness and sunlight incidence conditions, respectively.
Descrição
Palavras-chave
tecnologia de aplicação, estabilidade, adsorção foliar, aguapé, Eichhornia crassipes, spraying technology, stability, foliar adsorption, water hyacinth Eichhornia crassipes
Como citar
Planta Daninha. Sociedade Brasileira da Ciência das Plantas Daninhas , v. 23, n. 2, p. 287-294, 2005.