ABSTRACT
Background Dicamba is widely used in agricultural production in China, but it is extremely soluble in water and can be harmful to human health when it enters the body via water drinking. It is necessary to establish an accurate, sensitive, and rapid detection method to determine the residues of dicamba in domestic drinking water. Objective To establish two methods for the determination of dicamba residues in drinking water by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) and gas chromatography-tandem mass spectrometry (GC-MS/MS) respectively. Methods The conditions of the proposed method using HPLC-MS/MS included CAPCELL PAK ST chromatographic column, ammonium formate water solution and methanol as the mobile phase, and isocratic elution. The system was operated under multiple reaction monitoring mode and electrospray negative ionization mode. Trimethylsilylated diazomethane was used as a derivatizing agent for GC-MS/MS, and an external standard curve was used to evaluate the system. The residues of dicamba in seven water samples of tap water or secondary water supply from six regions in Chengdu were detected by the established systems to evaluate their applicability and to understand the status quo of dicamba residues in drinking water. Results For the HPLC-MS/MS, the linear range of dicamba was 1.00-100 μg·L−1, the regression equation was \begin{document}$\hat Y $\end{document}=1250.9X+2681.5, the correlation coefficient was 0.9988, the relative standard deviations were 1.23%-26.3%, the limit of detection was 0.95 μg·L−1, and the spiked recoveries were 91.8%-111%. For the GC-MS/MS, the linear range of dicamba was 0.200-10.0 μg·L−1, the regression equation was \begin{document}$\hat Y $\end{document}=190597X+40911, the correlation coefficient was 0.9993, the relative standard deviations were 0.64%-3.90%, the limit of detection was 0.18 μg·L−1, and the spiked recoveries were 97.3%-105%. No dicamba residue was identified in the seven water samples of tap water or secondary water supply from six regions in Chengdu by the proposed methods. Conclusion The two detection methods established in this study are sensitive and rapid, meet the requirements from the detection of dicamba residues in drinking water, and provide an experimental basis for subsequent research on the detection of dicamba residues. In the future, it is necessary to continue to pay attention to the pollution of dicamba in drinking water in Chengdu.
ABSTRACT
ABSTRACT The aim of this study was to induce and analyze embryogenic calli from two types of explants (leaves and meristems) of the hybrid Eucalyptus grandis x Eucalyptus urophylla. Leaves and meristems of plants kept in a nursery were disinfected and inoculated in Petri dishes containing MS culture medium supplemented with different concentrations of the growth regulator dicamba (1.13, 4.52, and 9.04 µM) and without it. At 60 days of culturing, the calli were analyzed by scanning electron microscopy and at 90 days were evaluated by light microscopy in regard to the embryogenic characteristics of the cells. Different type of calli were induced in leaf explants, designated as Type I with light yellow coloring, Type II with dark yellow coloring, and Type III of brown coloring; however, only Type I had embryogenic characteristics. In the meristematic explants, only one type of callus was induced, and it had embryogenic characteristics. At 90 days of culturing, the formation of somatic embryos in the different embryogenic stages was observed and the formation of procambium, protoderm, and ground meristem tissues. At 150 days of culturing, the concentration of 1.13 µM of dicamba was prominent in the formation of somatic embryos in the different embryogenic stages.
ABSTRACT
Dicamba is 3, 6-dichloro-2-methoxybenzoic acid and classified as a chemically related chlorophenoxy herbicide. This herbicide has been widely used for control of broad-leaved weeds. The poisoning is uncommon and of low toxicity, but massive self-ingestion may be fatal. We experienced a case of dicamba poisoning with rhabdomyolysis and acute renal failure in a 53-year-old male. This patient showed vomiting, confused mental status, and myotonia. Electrolyte abnormalities, rhabdomyolysis, and acute renal failure also developed together with fever, hepatotoxicity, pancreatic toxicity, hematologic abnormalities and cardiac ischemia. He was treated by 7 sessions of hemodialysis with supportive treatment and recovered.