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Coffee is one of the most consumed beverages in the world. Due to its commercial importance, the detection of impurities and foreign matters has been a constant concern in fraud verification, especially because it is difficult to percept adulterations with the naked eye in samples of roasted and ground coffee. In Brazil, the most common additions are roasted materials, such as husks, sticks, corn, wheat middling, soybean, and more recently - acai palm seeds. The performance and correlation of two chromatographic methods, HPLC-HPAEC-PAD and post-column derivatization HPLC-UV-Vis, were compared for carbohydrate analysis in coffee samples. To verify the correlation between the two methods, the principal component analysis for the same mix of triticale and acai seeds in different proportions with coffee was employed. The performance for detecting adulterations in roasted and ground coffee of the two methods was compared.

This work describes the development of a simple, sensitive and selective method based on high-performance liquid chromatography coupled to tandem mass spectrometry (LC-MS-MS) to determine antipsychotics (olanzapine, quetiapine, clozapine, haloperidol and chlorpromazine) along with antidepressants (mirtazapine, paroxetine, citalopram, sertraline, imipramine, clomipramine and fluoxetine), anticonvulsants (carbamazepine and lamotrigine) and anxiolytics (diazepam and clonazepam) in plasma samples obtained from schizophrenic patients. The samples were prepared by protein precipitation. The target drugs were separated on an XSelect SCH C18 column (100 mm × 2.1 mm × 2.5 µm) within 8.0 min by means of gradient elution. The drugs were then detected on a quadrupole tandem mass spectrometer equipped with an electrospray ionization source, operating in the multiple reactions monitoring mode and in the positive ionization mode. The LC-MS-MS method was linear range from subtherapeutic to toxic concentrations with lower limit of quantification values ranged from 0.2 to 5.0 ng mL(-1), precision with coefficient of variation values lower than 12%, and accuracy ranged from 90 to 108%. The developed method enabled successful analysis of the target drugs in plasma samples obtained from 51 schizophrenic patients. Therapeutic drug monitoring revealed that many of the evaluated schizophrenic patients presented altered plasma concentrations of the analyzed drugs. These altered concentrations resulted from pharmacokinetic interactions among the medications prescribed to treat schizophrenia.

A sensitive, reproducible, and rapid method was developed for the simultaneous determination of underivatized amino acids (aspartate, serine, glycine, alanine, methionine, leucine, tyrosine, and tryptophan) and neurotransmitters (glutamate and γ-aminobutyric acid) in plasma samples using hydrophilic interaction liquid chromatography coupled to triple quadrupole tandem mass spectrometry. The plasma concentrations of amino acids and neurotransmitters obtained from 35 schizophrenic patients in treatment with clozapine (27 patients) and olanzapine (eight patients) were compared with those obtained from 38 healthy volunteers to monitor the effectiveness of treatment. The chromatographic conditions separated ten target compounds within 3 min. This method presented linear ranges that varied from (lower limit of quantification: 9.7-13.3 nmol/mL) to (upper limit of quantification: 19.4-800 nmol/mL), intra- and interassay precision with coefficients of variation lower than 10%, and relative standard error values of the accuracy ranged from -2.1 to 9.9%. The proposed method appropriately determines amino acids and neurotransmitters in plasma from schizophrenic patients. Compared with the control group (healthy volunteers), the plasma levels of methionine in schizophrenic patients treated with olanzapine are statistically significantly higher. Moreover, schizophrenic patients treated with clozapine tend to have increased plasma levels of glutamate.

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