RESUMO
A new molecularly imprinted polymer modified with restricted access material (a hydrophilic external layer), (MIP-RAM) was synthesized via polymerization in situ in an open fused silica capillary. This stationary phase was used as sorbent for in-tube solid phase microextraction (in-tube SPME) to determine parabens in breast milk samples by ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). Scanning electron micrographs (SEM) illustrate MIP surface modification after glycerol dimethacrylate (hydrophilic monomer) incorporation. The interaction between parabens and MIP-RAM was investigated by Fourier-transform infrared (FTIR) spectroscopy. The Scatchard plot for MIP-RAM presented two linear parts with different slopes, illustrating binding sites with high- and low-affinity. Endogenous compounds exclusion from the MIP-RAM capillary was demonstrated by in-tube SPME/LC-UV assays carried out with blank milk samples. The in-tube SPME/UHPLC-MS/MS method presented linear range from 10 ng mL(-1) (LLOQ) to 400 ng mL(-1) with coefficients of determination higher than 0.99, inter-assay precision with coefficient of variation (CV) values ranging from 2 to 15%, and inter-assay accuracy with relative standard deviation (RSD) values ranging from -1% to 19%. Analytical validation parameters attested that in-tube SPME/UHPLC-MS/MS is an appropriate method to determine parabens in human milk samples to assess human exposure to these compounds. Analysis of breast milk samples from lactating women demonstrated that the proposed method is effective.
Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Leite Humano/química , Parabenos/análise , Parabenos/isolamento & purificação , Polímeros/síntese química , Microextração em Fase Sólida/métodos , Espectrometria de Massas em Tandem/métodos , Adsorção , Cromatografia Líquida de Alta Pressão/instrumentação , Feminino , Humanos , Interações Hidrofóbicas e Hidrofílicas , Lactação , Impressão Molecular , Parabenos/química , Polimerização , Polímeros/química , Dióxido de Silício/química , Microextração em Fase Sólida/instrumentação , Espectrometria de Massas em Tandem/instrumentaçãoRESUMO
AIM: To evaluate transcutaneous electrical nerve stimulation (TENS) used to relieve uterine contraction pain during breast-feeding in multiparous women. METHODS: A controlled and randomized clinical trial was performed with 32 post-partum multiparous women who were breast-feeding. The participants were randomized into an experimental (EG, n = 16) and a control group (CG, n = 16). Pain was assessed using the Numerical Rating Scale and the descriptors of the Present Pain Intensity (PPI - McGill) during two sequential feeds. In the first assessment, the post-partum women in the EG and CG were monitored while breast-feeding and questioned regarding the degree of uterine contraction pain. In the second assessment, which was performed at the next feed, the EG used TENS while the CG was monitored, with pain being reassessed following. In the EG, the TENS electrodes were placed between T10-L1 and S2-S4, with a frequency of 100 Hz, a pulse duration of 75 µs and amplitude adjusted to produce a strong and tolerable sensation for 40 min. A descriptive analysis of the data and comparative intra- and intergroup analyses were performed by means of a non-parametrical test, with a significance level P ≤ 0.05. RESULTS: The level of basal pain was 5.56 in the EG and 5.50 in the CG. In the intragroup analysis, the EG (P < 0.0001) and CG (P = 0.04) presented significant pain reduction. In the intergroup analysis, the EG had significant pain reduction (P < 0.01) in comparison to the CG. In the PPI analysis, a non-significant decrease in pain intensity was observed in the EG. CONCLUSION: TENS was found to be effective in reducing post-partum uterine contraction pain during breast-feeding.