Dispersive liquid-liquid microextraction (DLLME) is a fast and simple technique and applicable procedure for the analysis of xenobiotics in different biological matrices. We have developed a DLLME method for the determination of benzodiazepines in plasma samples using liquid chromatography-diode-array detection (LC-DAD). During method validation, relative standard deviation values of more than 20% were observed for both intra and inter-day associated with precision and accuracy. So, full method validation was unsuccessful. Critical aspects and flaws associated with DLLME for benzodiazepines determination in biological matrices has never been addressed. The majority of previous studies involving DLLME for benzodiazepines analysis either did not carry out a full method validation or they do not share any details regarding their full validation procedure. The current study has focused on the issues and pitfalls encountered upon method validation so that scientific groups worldwide can avoid unnecessary experiments and benefit from the present discussion. These observations reinforce the need to carry out such a process to guarantee the reliability of the results, even more so if one is intending its application for real case samples in the field of toxicological analysis. Indeed, full, and satisfactory method validation is paramount to provide adequate and trustworthy analytical results.

Gamma-hydroxybutyrate (GHB) is a depressant of the central nervous system able to promote disinhibition, anterograde amnesia and its use is related to Drug-Facilitated Crimes (DFC). Urine is the biological matrix of choice for toxicological analysis in victims of rape and/or theft in suspected victims of DFC. The aim of this work was the development of a simple and ultra-fast methodology for GHB determination in urine samples using GC-MS. Briefly, 250 µL of urine was pipetted in a vial and fortified with 10 µL (250 µg mL-1) of internal standard GHB-d6. Then, the sample was acidified and submitted to extraction with ethyl acetate. After stirring, the material was taken to a microcentrifuge (1 minute at 5000 rpm). Then the dried residue was derivatized with BSTFA + 1% TCMS for 10 min at 70 ºC before injection. This method was successfully validated according UNODC and EMEA guidelines on bioanalytical method validation with limit of detection and limit of quantification were 0.25 and 0.50 µg mL-1, respectively. Considering all steps for GHB determination, this analytical procedure allows the fastest detection of GHB in urine samples when compared to literature allowing the analysis of DFC suspect cases or clinical when endogenous GHB requires to be measured.

ABSTRACT Fluoroquinolones are a known antibacterial class commonly used around the world. These compounds present relative stability and they may show some adverse effects according their distinct chemical structures. The chemical hydrolysis of five fluoroquinolones was studied using alkaline and photolytic degradation aiming to observe the differences in molecular reactivity. DFT/B3LYP-6.31G* was used to assist with understanding the chemical structure degradation. Gemifloxacin underwent degradation in alkaline medium. Gemifloxacin and danofloxacin showed more degradation perceptual indices in comparison with ciprofloxacin, enrofloxacin and norfloxacin in photolytic conditions. Some structural features were observed which may influence degradation, such as the presence of five member rings attached to the quinolone ring and the electrostatic positive charges, showed in maps of potential electrostatic charges. These measurements may be used in the design of effective and more stable fluoroquinolones as well as the investigation of degradation products from stress stability assays.

O doping genético caracteriza-se pelo uso não terapêutico de células, genes e elementos gênicos, ou a modulação da expressão gênica com objetivo de aumentar o desempenho esportivo. Isto somente pode ser realizado através de manipulação gênica. Esta prática dopante caracteriza-se como virtualmente "indetectável", o que representa novos desafios analíticos para sua detecção. Esta revisão apresenta o doping genético e possíveis métodos de detecção para evitar futuras fraudes desportivas.

Gene doping is characterized by non-therapeutic use of cells, genes and genetic elements, or modulation of gene expression with the aim to increase sports performance. This can only be accomplished through gene manipulation. This doping practice is characterized as virtually "undetectable", which represents new challenges for analytical detection. This review presents and possible gene doping detection methods to prevent future sports cheats.

El dopaje genética se caracteriza por el uso no terapéutico de células, genes y elementos genéticos o la modulación de la expresión génica con el objetivo de aumentar el rendimiento deportivo. Esto sólo puede lograrse gracias la manipulación genética. Esta práctica dopante se caracteriza por ser casi "imperceptible", lo que representa nuevos retos para la detección analítica. Esto presenta la revisión y posible dopaje gen métodos de detección para prevenir los futuros tramposos en el deportes.

O paraquat é um herbicida de contato não-seletivo. É amplamente utilizado na agricultura em mais de 100 países, pois apresenta baixo custo, grande eficácia e não possui efeitos poluentes cumulativos para o solo. Porém, ele é um produto muito tóxico para humanos e animais, podendo causar intoxicações fatais, principalmente pela falta de um antídoto eficaz na reversão do quadro clínico. O paraquat atua mediante mecanismos de indução do estresse oxidativo, produção aumentada de radicais livres associada à depleção dos sistemas antioxidantes do organismo. Sua toxicidade acomete rins, fígado, músculos, cérebro, dentre outros. Os pulmões são considerados os órgãos-alvo deste herbicida, levando a severas injúrias como edema, hemorragia, inflamação intersticial e fibrose pulmonar. A falência respiratória grave é a causa comum de morte. O tratamento da intoxicação, atualmente, é baseado em medidas que diminuam a absorção e aumentem a excreção. Entretanto, o uso de agentes antioxidantes e antifibróticos vem sendo estudado, pois há interesse crescente no estudo de substâncias que possam servir como antídoto nas intoxicações, uma vez que o paraquat aumenta os índices de morbidade e mortalidade.

Paraquat is a nonselective contact herbicide. It is widely used in agriculture because it is inexpensive and highly efficient. Moreover, it is not present cumulative pollutant effects. However, it is a very toxic product both for humans and animals. The intoxication produced can be fatal mainly by the lack of an efficient antidote to revert the clinical state of the subject. Paraquat acts on the oxidative stress-induced mechanisms. Thus, there is the increased production of the free radicals associated with the depletion of antioxidant systems of the organism. Paraquat toxicity attacks kidneys, liver, muscles, and brain, but lungs are the target organs. Severe injuries are observed such as edema, hemorrhage, interstitial inflammation and pulmonary fibrosis, culminating in serious respiratory failure with death. Nowadays, the treatment of paraquat intoxication is based in decrease of the absorption and increases the excretion. Moreover, the use of antioxidants and antifibrotic agents has being studied. There is an increasing interest in studies about substances that can serve as antidote in the poisonings, once paraquat increases the morbidity and mortality.