Relative Matrix Effect in the Quantification of Nitroimidazoles and Dyes in Meat, Eggs, Shrimp, and Fish Using an Ethyl Acetate/Salting-Out Extraction and Isotope Dilution Ultra-High Performance Liquid Chromatography-Tandem Mass Spectrometry.

This paper presents the validation of a multiresidue method for quantifying seven nitroimidazoles and four dyes in poultry, pork, beef, eggs, shrimp, and fish. The average matrix factors of standard normalized to IS (0.82-1.

Validation of an UHPLC-MS/MS Method for Screening of Antimicrobial Residues in Eggs and Their Application to Analyses of Eggs from Laying Hens Subjected to Pharmacological Treatment.

A multiresidue method by UHPLC/MS-MS was optimized and validated for the screening and semiquantitative detection of antimicrobials residues from tetracyclines, aminoglycosides, quinolones, lincosamides, -lactams, sulfonamides, and macrolides families in eggs. A qualitative approach was used to ensure adequate sensitivity to detect residues at the level of interest, defined as maximum residue limit (MRL), or less. The applicability of the methods was assessed by analyzing egg samples from hens that had been subjected to pharmacological treatment with neomycin, enrofloxacin, lincomycin, oxytetracycline, and doxycycline during five days and after discontinuation of medication (10 days).

Optimization and validation method to evaluate the residues of β-lactams and tetracyclines in kidney tissue by UPLC-MS/MS.

Methods are validated by a process that defines the analytical requirements and confirms that the investigated method is capable of performing consistently. A quantitative and confirmatory method for determining the presence of β-lactam and tetracycline multiresidues in avian, bovine, equine, and swine kidney tissues using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was developed, optimized, and validated. Analytes were extracted from the kidneys by a mixture of water and acetonitrile, and the extract was then purified with hexane and C18 (dispersive phase).

[Breast biopsy performed by the helicoid biopsy technique: an experimental study].

Purpose: to assess the helicoid biopsy performance when carrying out breast biopsies.

Methods: thirty patients with breast cancer submitted to mastectomy were selected at random. Women with a tumor of petreous consistency, nonpalpable, submitted to previous surgical manipulation or containing fluid were excluded.