Evaluation of sample processing methods for the polar contaminant analysis of sewage sludge using liquid chromatography - mass spectrometry (LC/MS)

Monitoring of sewage sludge has proved the presence of many polar anthropogenic pollutants since LC/MS techniques came into routine use. While advanced techniques may improve characterizations, flawed sample processing procedures, however, may disturb or disguise the presence and fate of many target compounds present in this type of complex matrix before analytical process starts. Freeze-drying or oven-drying, in combination with centrifugation or filtration as sample processing techniques were performed followed by visual pattern recognition of target compounds for assessment of pretreatment processes. The results shown that oven-drying affected the sludge characterization, while freeze-drying led to less analytical misinterpretations.

A sensitive and robust lc-ms/ms method with monolithic column and electrospray ionization for the quantitation of efavirenz in human plasma: application to a bioequivalence study

An LC-MS/MS method has been developed for the determination of efavirenz (EFZ) in human plasma using hydrochlorothiazide as internal standard (I.S.). An ESI negative mode with multiple reaction-monitoring was used monitoring the transitions m/z 313.88→69.24 (EFZ) and 296.02→204.76 (I.S.). Samples were extracted using liquid-liquid extraction. The total run time was 2.0 min. The separation was achieved with HPLC-RP using a monolithic column. The assay was linear in the concentration range of 100 - 5000 ng mL-1. The mean recovery was 83%. Intra- and inter-day precision were < 9.5% and < 8.9%, respectively and accuracy was in the range ± 8.33%. The method was successfully applied to a bioequivalence study.

LC-MS/MS method applied to preclinical pharmacokinetic investigation of olanzapine-loaded lipid-core nanocapsules

In spite of different methods reported in the literature to determine olanzapine in biological fluids, all of them used high volumes of plasma. Therefore, the purpose of this paper was to develop an LC-MS/MS method using small plasma volume (0.1 mL) to apply in a preclinical pharmacokinetic investigation. The method was linear over the concentration ranges of 10 - 1000 ng mL-1. Extraction recoveries, stability, and validation parameters were evaluated. Results were within the acceptable limits of international guidelines. A significant decrease in clearance led to a significant 2.26-times increase in AUC0 - 6h of olanzapine-loaded lipid-core nanocapsules compared with free-olanzapine.

Desafios da química analítica frente às necessidades da indústria farmacêutica

The development of liquid chromatography-mass spectrometric (LC-MS) techniques in the last few decades has made possible the analysis of trace amounts of analytes from complex matrices. With LC, the analytes of interest can be separated from each other as well as from the interfering matrix, after which they can be reliably identified thanks to the sensitivity and specificity of MS. LC-MS has become an irreplaceable tool for many applications, ranging from the analysis of proteins or pharmaceuticals in biological fluids to the analysis of toxic substances in environmental samples. In different segments of Brazilian Industry mass spectrometry has an important role, e.g. in the pharmaceutical industry in the development of generic formulations, contributing to the growth of Industry and social inclusion. However, the Brazilian chemists until this moment don't have an effective role in this new segment of the analytical chemistry in Brazil. The present paper shows the actual scenario for mass spectrometry in the pharmaceutical industry, emphasizing the need of a revision of graduation courses to attend the needs of this growing market.

Flavonoids in Astragalus corniculatus

Nine flavonoids were identified in aerial parts of Astragalus corniculatus Bieb. (Fabaceae) by liquid chromatography coupled with ionspray mass spectrometry in the tandem mode (LC/MS/MS) with negative ion detection. Vitexin, orientin and eriodictyol-7-O-glucoside are obtained for the first time in genus Astragalus L, and isorhamnetin-3-O-glucoside in the species.

Development and validation of a dissolution test with reversed-phase liquid chromatography analysis for rupatadine in tablet dosage forms

A dissolution test for in vitro evaluation of tablet dosage forms containing 10 mg of rupatadine was developed and validated by RP-LC. A discriminatory dissolution method was established using apparatus paddle at a stirring rate of 50 rpm with 900 mL of deaerated 0.01 M hydrochloric acid. The proposed method was validated yielding acceptable results for the parameters evaluated, and was applied for the quality control analysis of rupatadine tablets, and to evaluate the formulation during an accelerated stability study. Moreover, quantitative analyses were also performed, to compare the applicability of the RP-LC and the LC-MS/MS methods.

Principais técnicas de preparo de amostra para a determinação de resíduos de agrotóxicos em água por cromatografia líquida com detecção por arranjo de diodos e por espectrometria de massas

The determination of pesticide residues in water samples by Liquid Chromatography require sample preparation for extraction and enrichment of the analytes with the minimization of interferences to achieve adequate detection limits. The Solid Phase Extraction (SPE), Solid Phase Microextraction (SPME), Stir Bar Sorptive Extraction (SBSE) and Dispersive Liquid-Liquid Microextraction (DLLME) techniques have been widely used for extraction of pesticides in water. In this review, the principles of these sample preparation techniques associated with the analysis by Liquid Chromatography with Diode Array Detection (LC-DAD) or Mass Spectrometry (LC-MS) are described and an overview of several applications were presented and discussed.

Sensitive method for determination of piplartine, an alkaloid amide from Piper species, in rat plasma samples by liquid chromatography-tandem mass spectrometry

Piplartine (PPTN) is an alkaloid amide found in Piper species that presents different activities. PPTN determination in rat plasma is necessary to better understand its biological effects. The aim of this study was to develop a sensitive LC-MS/MS method for the determination of PPTN in rat plasma. The performance criteria for linearity, sensitivity, precision, accuracy, recovery, and stability have been assessed and were within the recommended guidelines. The validated method proved to be suitable in a pilot study of PPTN kinetic disposition in rat plasma after a single intraperitoneal dose, and represents an appropriate tool to further pharmacokinetic studies.

Análises quali e quantitativas de micotoxinas em águas da cadeia produtiva do arroz por CCD e CCDAE

This study validated a simple and applied method for determining mycotoxins aflatoxin B1, aflatoxin B2, ochratoxin A, zearalenone and deoxynivalenol, in water from the rice production chain. Five solvent combinations for extraction were tested, with quantification performed by TLC/HPTLC and confirmation by LC-MS/MS. Mycotoxins in water from field and rice industries were evaluated. Mycotoxin recovery levels were around 90%. Two samples from rice parboiling waste were contaminated (deoxynivalenol/aflatoxin B1, 110/9 ng mL-1; and deoxynivalenol, 100 ng mL-1). Zearalenone, deoxynivalenol and ochratoxin A (36, 30 and 28%) were carried to soaking water during parboiling.

Occurrence, biological activities and 13C NMR data of amides from Piper (Piperaceae)

This manuscript describes an update review with up to 285 references concerning the occurrence of amides from a variety of species of the genus Piper (Piperaceae). Besides addressing occurrence, this review also describes the biological activities attributed to extracts and pure compounds, a compiled 13C NMR data set, the main correlations between structural and NMR spectroscopic data of these compounds, and employment of hyphened techniques such as LC-MS, GC-MS and NMR for analysis of amides from biological samples and crude Piper extracts.

Atividade de extratos de Arrabidaea chica (Humb. & Bonpl.) Verlot obtidos por processos biotecnológicos sobre a proliferação de fibroblastos e células tumorais humanas

Arrabidaea chica (H&B) Verlot is a plant popularly known as Pariri and this species is a known source of anthocyanins, flavonoids and tannins. This report describes an approach involving enzymatic treatment prior to extraction procedures to enhance A chica crude extract anticancer activity. Anticancer activity in human cancer cell lines in vitro using a 48 h SRB cell viability assay was performed to determine growth inhibition and cytotoxic properties. The final extraction yield without enzyme treatment was higher (24.28%) compared to the enzyme-treated material (19.03%), with an enhanced aglycones anthocyanin ratio as determined by HPLC- DAD and LC-MS with direct infusion.

Aspectos analíticos e regulatórios na determinação de resíduos de macrolídeos em alimentos de origem animal por cromatografia líquida associada à espectrometria de massas

This is an overview of LC-MS techniques applied for macrolide determination in food, including sample preparation and method validation, as well as the policies adopted by international agencies regarding their presence in food. Techniques for the analysis of macrolides in food normally include solid phase or liquid-liquid extraction followed by HPLC. UHPLC presents advantages in running time, detectability and solvent consumption. Triple-quadrupoles are the most common analyzers in instruments used for the determination of contaminants in food, but time-of-flight and ion-trap spectrometers have been successfully applied for analyses focusing on the investigation of structural formula or the presence of degradation products.

Resíduos de medicamentos veterinários em leite e ovos

The use of veterinary drugs in food producing animals may result in the presence of residues in foods, including milk and eggs. Immunoassay or microbiological tests are used to screen for residues, but chromatographic methods are needed to confirm positive results. In most methods, the sample is extracted with acetonitrile, submitted to clean up or directly analyzed by LC-MS/MS. Results of the Brazilian governmental monitoring programs from 2006 to 2011 have shown that the antiparasitic ivermectin was the drug most frequently found in milk. Residues in eggs are only monitored by one of the programs, and few studies have reported the incidence of veterinary drugs in this matrix in Brazil.

Desenvolvimento de procedimento de extração para análise de sedativos e B-bloqueadores em rim suíno

A procedure was developed for determination of 5 sedatives and 14 β-blockers in swine kidney and subsequent analysis by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). Three different procedures for extraction were tested, evaluated through recovery studies. The procedure using acetonitrile for extraction and cleanup with freezing at low temperature and dispersive solid phase extraction using 500 mg celite® 545 before the concentration step presented the better results. The dried samples were redissolved with methanol and analyzed using a LC-MS/MS system with electrospray ionization (ESI) operating in positive MRM mode. The recovery values for this procedure were in the 75-88% range. The robustness of the method was tested against small variations. The method was used to analyze carazolol, azaperone and azaperol in collaborative assay, obtaining results close to designed value.

Avaliação da intoxicação de cultivares de cana-de-açúcar e I. grandifolia ao amicarbazone

O objetivo deste trabalho foi avaliar a intoxicação de planta daninha e cultivares de cana-de-açúcar ao amicarbazone. Para isso, utilizou-se Ipomoea grandifolia como planta daninha representante e os cultivares de cana-de-açúcar PO8862, SP80 3280 e RB83 5486, caracterizados como sensível, intermediário e tolerante aos herbicidas, respectivamente. Foi verificado o consumo de água e quantificada a concentração do amicarbazone em seiva de xilema dos três cultivares de cana-de-açúcar e de I. grandifolia por meio da bomba de Schollander e da cromatografia e espectrometria de massas (LC-MS). A intoxicação das plantas foi verificada através de leituras da fluorescência, com auxílio do fluorômetro portátil, que permitiu a correlação da taxa de transporte de elétrons (ETR) com a concentração de amicarbazone absorvido pelos cultivares de cana-de-açúcar e por I. grandifolia. Verificou-se, através do experimento, que a redução dos valores da ETR pode ser utilizada para indicar o nível de intoxicação de I. grandifolia e de plantas de cana-de-açúcar ao amicarbazone. I. grandifolia destacou-se em relação à cana-de-açúcar pela maior sensibilidade ao amicarbazone. A suscetibilidade diferencial dos cultivares de cana-de-açúcar PO8862, SP80 3280 e RB83 5486 pode ser justificada, possivelmente, pela absorção diferencial do amicarbazone entre os cultivares.