Lucia Helena Pinto Bastos

Concentração residual de hexaclorociclohexano em área contaminada na Cidade dos Meninos, Duque de Caxias, Rio de Janeiro, Brasil, após tratamento com óxido de cálcio

Hexachlorocyclohexanes (HCHs) are currently considered potentially carcinogenic to humans. In Brasil, severe soil contamination by HCHs has been identified at Cidade dos Meninos, Duque de Caxias, Rio de Janeiro, where an old HCH factory was abandoned 40 years ago, leaving 1,700 local residents at risk. Calcium oxide treatment was performed on the most heavily contaminated (focus) area. Analysis of superficial soil samples collected years after treatment still showed high residual HCH. Contamination levels as high as 6,200mg/Kg and 7,320mg/Kg were found for alpha- and beta-HCH isomers. For the gamma- and delta-HCH isomers, concentrations reached up to 140mg/Kg and 530mg/Kg, respectively. The results showed that calcium oxide treatment was not efficient to decontaminate the soil in this area.

Monitoramento de resíduos de agrotóxicos da classe dos organofosforados por CG-DFC em amostras de leite fluído e em pó

Samples of whole fluid pasteurized, UHT and powdered milk were analyzed for the presence of organophosphorus pesticide residues (OPR) using the QuEChERS method with detection by GC-FPD and confirmation by UPLC-MS/MS. A total of 23% of fluid milk samples and 27% of powdered milk samples contained at least one organophosphorus residue. The OPR found in the samples showed these can reach the milk and remain even after pasteurization, sterilization and drying processes. Some domestic sanitary residues were also present in the powdered milk samples. These residues have no LMR in Brazilian food legislation and are therefore not taken into account in food intake evaluations. There was an unidentified chromatographic peak in 30% of all the liquid and powdered milk samples, indicating the presence of some other contaminant.

Implementação de método analítico para determinação de resíduos de organofosforados em leite por cromatografia a gás com detector fotométrico de chama

This paper regards the implementation of the QuEChERS method for the analysis by GC-FPD of 53 different pesticides from the organophosphate class, in whole UHT and pasteurized milk. Selectivity, linearity, repeatability, recovery and limits of detection and quantification were evaluated. Of all pesticide recoveries, 51 were considered satisfactory since the values ranged from 70 to 120% with RSD < 20%. The quantification limits ranged from 0.005 to 0.4 mg kg-1. The QuEChERS method was suitable for determination of 52 pesticides, presenting several advantages - quick, cheap, easy, effective, rugged and safe - with regard to other traditional methodologies.

Ensaio de proficiência para análise de ditiocarbamatos em polpa de banana

A proficiency assay of the determination of dithiocarbamate pesticide residues in banana was carried out. Fourteen laboratories participated in this study. Homogeneity and stability testing were performed by INCQS on the samples sent to the laboratories. Analytical results supplied by the pesticide residues laboratory of the VWA/KvW, Amsterdam, Holland, were used to define the designated value for the thiram concentration in the study samples. RESULTS: Fifty percent of the participating laboratories had satisfactory results. Efforts are needed to improve the precision of the analytical results and to decrease the number of false negative results observed.

Implementação da técnica de extração de dispersão da matriz em fase sólida ("MSPD") para determinação de resíduos de agrotóxicos em laranjas

A multiresidue method of extraction based on matrix solid-phase dispersion (MSPD) technique was optimized and validated for chromatographic analyses of twenty seven pesticides residues [hexachlorocyclohexane (HCH) isomers (α,β,γ,δ), dieldrin, endrin, heptachlor and its epoxide (HE),α and β-endosulfan, o,p’-DDD, p,p’-DDD, o,p’-DDE, p,p’-DDE, o,p’-DDT p,p’-DDT, dicofol, methoxychlor, mirex, hexachlorobenzene(HCB), chlorotalonil, parathion methyl, fenitrothion, malathion, folpet, diazinon, permethrin (cis and trans) in oranges. The sample was blended with C18and then the homogenized sample was introduced onto a glass column containing silica. Ten mL of ethylacetate was added to the column as elution solvent. The eluent was concentrated, diluted in isooctane and 1µL was injected intothe gas chromatograph. The analyses of pesticides were performed using a GC/ECD. Confirmation was done by mass spectrometry. The recovery ranged from 70 to 120% in the concentration range of 0.02 to 2.0mg/kg. The limits of quantification ranged from 0.01to 0.5mg/kg.