A review of the application of hollow-fiber liquid-phase microextraction in bioanalytical methods - A systematic approach with focus on forensic toxicology.

Over the past three decades, many studies employing hollow-fiber liquid-phase microextraction (HF-LPME) bioanalytical methods have been published. The basic mechanism of extraction relies on the migration of the analytes through a liquid membrane sustained in the pores of the walls of a porous hollow fiber, and from there into an acceptor phase present in the lumen of the fiber. The mass transfer occurs by passive diffusion and it can be enhanced by using a carrier or applying an electrical potential across the phases. This type of extraction method presents many advantages over classical techniques, such as high preconcentration factor, clean extracts, and a green chemistry approach. Due to its advantages, and considering that no study systematically compiled the characteristics of the published methods in one single accessible source of information, the aim of this systematic review is to assess the data regarding bioanalytical methods, compile, and analyse the studies published until up to October of 2017. The data source used for the systematic review were Pubmed, Web of Science, and Science Direct, and 171 studies were included in the final review by two independent reviewers, resulting in a reliable and accessible source of information about bioanalytical methods employing HF-LPME.

Improved quantification of CSF bilirubin in the presence of hemoglobin using least squares curve-fitting.

Subarachnoid hemorrhage (SAH) is a dangerous neurological event with a very short time window for early diagnosis. Clinical diagnoses performed in a lab seek to quantify bilirubin in cerebrospinal fluid (CSF) as a biomarker for SAHs; however laboratory assays suffer from lengthy protocols, interference from hemoglobin, and the availability of expertise. Substantial improvements in the determination of bilirubin concentration in the presence of hemoglobin in CSF are demonstrated in this work. Concentration estimates within 15% for bilirubin in the range of 0.2 to 1.6 mg /dl were determined for CSF samples containing fresh hemoglobin concentrations ranging from 0.05 to 0.25 g/dl. To demonstrate extensibility of the system with respect to more complete mock SAH samples, sample sets with one additional species of both hemoglobin and bilirubin, methemoglobin and alpha-bilirubin, respectively, were tested and yielded results within 25% of actual values, as measured by standard chemical assays of preparations prior to mixing.