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The new ultra-high performance liquid chromatography method with tandem mass spectrometry detection (UHPLC-MS/MS) has been optimized to allow fast, selective, and high-throughput analysis of two Candida albicans quorum sensing molecules (QSM), farnesol and tyrosol. The problem of the presence of the interference in the samples and system was successfully solved by careful optimization of chromatographic conditions. Charged hybrid stationary phase modified with pentafluorophenyl group and optimized gradient elution provided adequate separation selectivity and peak shapes. The impurity was identified as dibutyl phthalate and had the same m/z ions as farnesol leading to an important interference on selected reaction monitoring channel. Two different types of biological matrices originating from vaginal fluid, supernatant and sediment, were analysed. Micro-solid phase extraction in pipette tips was optimized for the selective isolation of QSM from the supernatant. The insufficient retention of farnesol on the extraction sorbent was improved when 1% of organic solvent was added prior to extraction, while the retention of tyrosol was only possible when using combined C8 and polymer sorbent type. Strong retention of farnesol had to be solved by increasing elution solvent strength and volume up to 600 μL. However, this approach did not allow the pretreatment of sediment samples due to the sorbent clogging. Therefore, our previously developed protein precipitation method was modified and validated to analyse the sediments. New developed UHPLC-MS/MS method provided suitable accuracy and precision for the determination of QSM in vaginal fluid while using only 50 μL sample volume and two different sample preparation methods.

γ-Hydroxybutyric acid (GHB) is a powerful central nervous system depressant, currently used in medicine for the treatment of narcolepsy and alcohol dependence. In recent years, it has gained popularity among illegal club drugs, mainly because of its euphoric effects as well as doping agent and date rape drug. The purpose of the present work was the development of a rapid analytical method for the analysis of GHB in innovative biological matrices, namely dried blood spots (DBSs) and dried urine spots (DUSs). The analytical method is based on capillary zone electrophoresis with indirect UV absorption detection at 210 nm and capillary wall dynamic coating. The background electrolyte is composed of a phosphate buffer containing nicotinic acid (probe for detection) and cetyltrimethylammonium bromide (CTAB, reversal of electroosmosis in wall dynamic coating). The influence of probe and CTAB concentration, together with buffer pH, on migration time and signal response was investigated. Under the optimized conditions, analytical linearity and precision were satisfactory; absolute recovery values were also high (>90 %); the use of dried matrices (DBSs and DUSs) was advantageous as an alternative matrix to classical ones. No interferences were found either from the most common exogenous or from endogenous compounds. This analytical approach can offer a rapid, precise and accurate method for GHB determination in innovative biological samples, which could be important for screening purposes in clinical and forensic toxicology. Graphical Abstract CE method, by combined indirect UV detection and dynamic coating, for GHB determination in DBSs and DUSs.

The amino acid content of fruit and fruit-derived foods is studied intensely because of the contribution to nutritional value, aroma, taste and health-promoting effects and their possible use as markers of origin and authenticity. In this review, based on 101 references, the most recent trends in the analysis of amino acids are presented: the most important techniques, the different sample treatment procedures (including derivatisation) and the most frequent applications are described and compared. Pertinent publications were retrieved from Scopus and Web of Knowledge database searches lastly performed in February 2012 with the keywords "amino acid", "analysis", "liquid chromatography", "gas chromatography", "electrophoresis", "fruit", and "vegetables"; the time limit was set from the year 2000 onwards. Although amino acids have been analysed in foods for decades, new technical possibilities and advancements have allowed ever-increasing accuracy and targeting of the methods in order to overcome the challenges posed by the complex plant matrices and their high intrinsic variability.

A high-performance liquid chromatographic method has been developed for the simultaneous determination of classical neuroleptics (chlorpromazine, haloperidol, loxapine and clotiapine), atypical antipsychotics (clozapine, quetiapine and risperidone) and their active metabolites (N-desmethylclozapine, clozapine N-oxide and 9-hydroxyrisperidone) in human plasma. Separation was obtained by using a C8 reversed-phase column and a mobile phase composed of 70% aqueous phosphate buffer containing triethylamine at pH 3.0 and 30% acetonitrile. The UV detector was set at 238 nm and amitriptyline was used as the internal standard. A careful pre-treatment procedure of plasma samples was developed, using solid-phase extraction with cyanopropyl cartridges, which gives high extraction yields (>or=93%). The limits of quantitation (LOQ) were always lower than 2.6 ng mL-1 and the limits of detection (LOD) were always lower than 0.9 ng mL-1 for all analytes. The method was applied with success to plasma samples from schizophrenic patients undergoing polypharmacy with two or more different antipsychotics. Precision data and accuracy results were satisfactory and no interference from other central nervous system (CNS) drugs was found. Hence the method is suitable for the therapeutic drug monitoring (TDM) of the analytes in psychotic patients' plasma.