Evaluation of the nicotine metabolite ratio in smoking patients treated with varenicline and bupropion.

Smoking is the leading cause of preventable death worldwide. It is responsible for several types of cancer, cardiovascular diseases, and diseases of the reproductive system, among others. Therefore, advances in research are increasingly necessary in order to make smoking cessation treatment more effective.

Online restricted access molecularly imprinted solid-phase extraction coupled with liquid chromatography-mass spectrometry for the selective determination of serum bile acids.

A rapid and sensitive online restricted access molecularly imprinted solid-phase extraction method coupled to a liquid chromatography-mass spectrometry (LC-MS) system for simultaneous determination of serum bile acids as well as their taurine and glycine conjugates was developed. Reversible liver damage of workers exposed to volatile organic solvents can be investigated based on the level of the analyzed molecules. A restricted access molecularly imprinted polymer coated with bovine serum albumin (RAMIP-BSA) was synthesized and used as the extraction phase.

Online biological sample preparation with restricted access hybrid carbon nanotubes for determination of anti-smoking drugs.

Untreated samples were injected directly into a column switching system, an online SPE technique, using an extraction column packed with restricted access hybrid carbon nanotubes (RAHCNTs), a novel type of restricted access material, in an ultra-high performance liquid chromatography, coupled to a mass spectrometer (UHPLC-MS/MS). The synthesis of used restricted access material was relatively simple, quick, and reproducible, and had a high material yield. Compared to its predecessor, which is covered with bovine serum albumin (Restricted Access Carbon Nanotubes-RACNTs), RAHCNTs have improved performance when used for the analysis of organic compounds.

Multivariate Optimization of an SPME Technique for GC-MS Analysis of Urinary BTX.

Volatile organic compounds (VOCs), such as benzene, toluene and xylenes (BTX), are recognized as environmental contaminants due to their acute and chronic toxic effects, and toluene is a substance contained in products used in inhalants. In this way, methods able to determine these substances in non-invasive matrices offer great applicability for assessing acute exposure. In this study, a functionalized polymer, chloropropyltrimethoxysilane/polydimethylsiloxane, was evaluated as a potential material to be used in solid-phase microextraction for the quantification of BTX in urine by gas chromatography coupled to mass spectrometry (GC-MS).

Molecularly Imprinted Solid Phase Extraction Aiding the Analysis of Disease Biomarkers.

Low concentrations of biomarkers as well as the complexity of biological samples make the clinical diagnoses of several diseases a challenging task. Sample preparation protocols remain a fundamental piece in the puzzle of analytical processes, and smart sorbents including molecularly imprinted polymers (MIPs) have been successfully used in this case. In this review, we depict the state of art for the rational design of MIPs to be used in solid phase extraction of disease biomarkers from biological samples.

Toxicological analyses: analytical method validation for prevention or diagnosis.

The need for reliable results in Toxicological Analysis is recognized and required worldwide. The analytical validation ensures that a method will provide trustworthy information about a particular sample when applied in accordance with a predefined protocol, being able to determine a specific analyte at a distinct concentration range for a well-defined purpose. The driving force for developing method validation for bioanalytical projects comes from the regulatory agencies.

Restricted access carbon nanotube for microextraction by packed sorbent to determine antipsychotics in plasma samples by high-performance liquid chromatography-tandem mass spectrometry.

This manuscript describes the development of the restricted access carbon nanotube (RACNT) as a selective stationary phase for microextraction by packed sorbent (MEPS) to determine antipsychotics (chlorpromazine, clozapine, olanzapine, and quetiapine) in untreated plasma samples from schizophrenic patients by ultra-high liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). The synthesis was achieved by chemically covering commercial multi-walled carbon nanotubes with bovine serum albumin (BSA) to subsequently pack the material in a polyethylene conical tube (1000 μL). The RACNTs' sorbents were able to exclude about 97% of the plasma proteins, maintaining the same performance for about 100 assays.

Serum analysis in women and in vitro skin assay for the assessment of exposure to parabens in antiperspirants.

The present study assessed the exposure to methylparaben (MP) and propylparaben (PP) from antiperspirants in serum of 24 women aged 20-30 years old and an in vitro skin assay. An effective liquid chromatography-tandem mass spectrometry method for the determination of MP and PP levels in serum was developed and validated in the range of 10-100 μg/L; the method was fast, simple, sensitive, linear, precise, and accurate. In addition, a simple and rapid liquid chromatography-ultraviolet detection method for the determination of MP and PP levels in antiperspirants was developed and validated in the range of 2-26 mg/L, which presented satisfactory linearity, precision, and accuracy.

Biological sample preparation by using restricted-access nanoparticles prepared from bovine serum albumin: application to liquid chromatographic determination of β-blockers.

Restricted-access nanoparticles (RANPs) were prepared from bovine serum albumin by coacervation. They have an average sized of 311 nm. They were characterized and used to capture the β-blockers atenolol, metoprolol and propranolol from untreated biological samples.

Online extraction of antihypertensive drugs and their metabolites from untreated human serum samples using restricted access carbon nanotubes in a column switching liquid chromatography system.

A novel analytical method was developed to determine 5 antihypertensive drugs of different pharmacological classes (angiotensin-converting enzyme inhibitors, calcium channel blockers, α-2 adrenergic receptor agonists, angiotensin II receptor blockers, and aldosterone receptor antagonists) and some of their metabolites in human serum. The untreated samples were directly analyzed in a column switching system using an extraction column packed with restricted access carbon nanotubes (RACNTs) in an ultra-high performance liquid chromatography coupled to a mass spectrometer (UHPLC-MS/MS). The RACNTs column was able to exclude approximately 100% of proteins from the samples in 2.

Direct extraction of tetracyclines from bovine milk using restricted access carbon nanotubes in a column switching liquid chromatography system.

This paper describes, for the first time, the use of restricted access carbon nanotubes (RACNTs) in the analysis of tetracyclines from milk samples, in a multidimensional liquid chromatographic system. Milk samples were initially acidified and centrifuged, and then the supernatant was directly analyzed in a column switching system in backflush configuration employing an extraction column of RACNTs. The sorbent was able to exclude all the remained proteins in less than 2.

New advances in restricted access materials for sample preparation: A review.

The determination of organic and inorganic analytes from biological samples need efficient sample preparation procedures in order to capture the analyte in a media with many macromolecules, which can cause analytical errors and problems with the instruments. Thus, "intelligent" sorbents, called restricted access materials (RAMs), have been widely used with these samples, due to their ability to retain analytes and exclude macromolecules. These materials have been obtained by modifying the external surfaces of conventional sorbents (e.