RESUMO
A new method using gel permeation chromatography (GPC) cleanup followed by ultra-performance liquid chromatography combined with tandem mass spectrometry (UPLC-MS-MS) has been established for simultaneous determination of 18 carbamate pesticides in nuts (chestnut and pine nut). Recoveries obtained by fortifying nut (spiking at 0.02 mg/kg) range from 70.21% to 89.56%. The proposed method features good sensitivity. Its limits of quantification are low enough to allow pesticide residues to be determined at concentrations below the maximum residue levels legally accepted. The precision, expressed as relative standard deviation, ranges from 2.26% to 4.07%.
Assuntos
Carbamatos/análise , Cromatografia em Gel/métodos , Cromatografia Líquida de Alta Pressão/métodos , Nozes/química , Resíduos de Praguicidas/análise , Espectrometria de Massas em Tandem/métodos , Cromatografia em Gel/economia , Cromatografia Líquida de Alta Pressão/economia , Fagaceae/química , Limite de Detecção , Pinus/química , Espectrometria de Massas em Tandem/economia , Fatores de TempoRESUMO
Coagulase-negative staphylococci produce an exocellular glycolipid antigen which has potential as a serological marker of infection in bone. The value of this newly detected antigen was investigated by enzyme-linked immunosorbent assay (ELISA) in 15 patients with culture-proven infection of prostheses caused by Gram-positive bacteria. The antigen was purified by gel-permeation chromatography from the culture supernatants of coagulase-negative staphylococci grown in a chemically defined medium. There were significant differences (p < 0.0001) between the serum IgG and IgM levels in patients with infection due to Gram-positive staphylococci and those of a control group of 32 patients with no infection. The ELISA test, which has potential for the diagnosis of infection, may be valuable in distinguishing between staphylococcal infection around prostheses and aseptic loosening.