High performance liquid chromatography-high resolution mass spectrometry and micropulverized extraction for the quantification of amphetamines, cocaine, opioids, benzodiazepines, antidepressants and hallucinogens in 2.5 mg hair samples

A high performance liquid chromatography-high resolution mass spectrometry (HPLC-HRMS) method for simultaneous screening and quantification of 28 drugs was developed and validated for 2.5 mg hair samples. Target drugs and their metabolites included amphetamines, cocaine, opioids, benzodiazepines, antidepressants, and hallucinogens. After decontamination, hair samples were extracted with 200 μL of a mixture of water: acetonitrile:1 M trifluoroacetic acid (80:10:10, v/v) using a 5 min simultaneous pulverization/extraction step. The extracts were analysed by HPLC-HRMS in an Orbitrap at a nominal resolution of 60,000, with concomitant in source collisional experiments (in source CID). Gradient elution on an Atlantis T3 column resolved 28 target compounds and 5 internal standards. Total chromatographic run time was 26 min. Calibration was achieved by linear regression analysis utilizing six calibration points; R2 ranged from 0.9964 to 0.9999, the limits of quantification were 0.1 ng/mg for 8 compounds, 0.2 ng/mg for 16 compounds and 0.5 ng/mg for 4 compounds; mean relative errors from -21% to +23% were obtained; relative standard deviation, used to estimate repeatability and intermediate reproducibility at three concentrations, was always less than 20%. Process efficiency and recoveries for all analytes were better than 65 and 73%, respectively, at any concentration. The method was applied to hair samples from forensic investigations that contained a broad assortment of drugs of abuse and pharmaceuticals. The use of concomitant HRMS full scan and CID afforded the possibility of retrospective analysis for discovering untargeted drugs.     

Multi-class determination of around 50 pharmaceuticals, including 26 antibiotics, in environmental and wastewater samples by ultra-high performance liquid chromatography-tandem mass spectrometry

A multi-class method for the simultaneous quantification and confirmation of 47 pharmaceuticals in environmental and wastewater samples has been developed. The target list of analytes included analgesic and anti-inflammatories, cholesterol lowering statin drugs and lipid regulators, antidepressants, anti-ulcer agents, psychiatric drugs, ansiolitics, cardiovasculars and a high number (26) of antibiotics from different chemical groups. A common pre-concentration step based on solid-phase extraction with Oasis HLB cartridges was applied, followed by ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) measurement. All compounds were satisfactorily determined in just one single injection, with a chromatographic run time of only 10 min. The process efficiency (combination of the matrix effect and the extraction process recovery) for the 47 selected compounds was evaluated in nine effluent wastewater (EWW) samples, and the use of different isotope-labelled internal standards (ILIS) was investigated to correct unsatisfactory values. Up to 12 ILIS were evaluated in EWW and surface water (SW). As expected, the ILIS provided satisfactory correction for their own analytes. However, the use of these ILIS for the rest of pharmaceuticals was problematic in some cases. Despite this fact, the correction with analogues ILIS was found useful for most of analytes in EWW, while was not strictly required in the SW tested. The method was successfully validated in SW and EWW at low concentration levels, as expected for pharmaceuticals in these matrices (0.025, 0.1 and 0.5 μg/L in SW; 0.1 and 0.5 μg/L in EWW). With only a few exceptions, the instrumental limits of detection varied between 0.1 and 8 pg. The limits of quantification were estimated from sample chromatograms at the lowest spiked levels tested and normally were below 20 ng/L for SW and below 50 ng/L for EWW. The developed method was applied to the analysis of around forty water samples (river waters and effluent wastewaters) from the Spanish Mediterranean region. Almost all the pharmaceuticals selected in this work were detected, mainly in effluent wastewater. In both matrices, analgesics and anti-inflammatories, lipid regulators and quinolone antibiotics were the most detected groups.     

Direct rapid analysis of multiple PPCPs in municipal wastewater using ultrahigh performance liquid chromatography–tandem mass spectrometry without SPE pre-concentration

Ultrahigh performance liquid chromatography–tandem mass spectrometry (UHPLC–MS/MS) was utilized to develop a rapid, sensitive and reliable method without solid phase extraction (SPE) pre-concentration for trace analysis of 11 pharmaceuticals and personal care products (PPCPs) in in?uent and ef?uent from municipal wastewater treatment plants (WWTPs). This method not only shortened the analysis time but also reduced analysis cost significantly by omitting SPE process and avoiding the consumption of SPE cartridge. Detection parameters for UHPLC–MS/MS analysis were optimized, including sample pH, eluent, mobile phase (solvent and additive), column temperature, and ?ow rate. Under the optimal conditions, all analytes were well separated and detected within 8.0 min by UHPLC–MS/MS. The method quantification limits (MQLs) for the 11 PPCPs ranged from 0.040 to 88 ng L⁻¹ and from 0.030 to 90 ng L⁻¹ for influent and effluent, respectively. The matrix effect was systematically investigated and quantified for different types of samples. The analysis of in?uent and ef?uent samples of two WWTPs in Hong Kong revealed the presence of 11 PPCPs, including acyclovir, benzophenone-3, benzylparaben, carbamazepine, ethylparaben, fluconazole, fluoxetine, methylparaben, metronidazole, propylparaben, and ranitidine. Their concentrations ranged from 9.1 to 1810 ng L⁻¹ in influent and from 6.5 to 823 ng L⁻¹ in effluent samples collected from Hong Kong WWTPs.     

Folarographic Behaviour of Nitrendipine

Abstract

Nifedipine, a calcium antagonist drug, proceduces a well-defined polarographic wave due to the four-electron, four-proton reduction of the nitro group. This peak is diffusion-controlled and shows a linear dependence on the Nitrendipine concentration. This behaviour is used for analytical purposes in determining Nitrendipine content in commercial preparations. The method is sensitive enough to be applied to single tablet, assays.

However, the principal advantage lies in the prompt determination. Preparation of the samples is easy and no extraction procedure is required. The method is recommended for uniformity contents studies and stability tests in day-to-day routine analyses.     

Separation methods for captopril in pharmaceuticals and biological fluids

Captopril (CAP) is an orally active angiotensin-converting enzyme (ACE) inhibitor and has been widely used for management of hypertension and congestive heart failure. CAP lacks an aromatic chromophore required for facile direct UV detection and also has two chiral centers. These factors can render the determination of CAP in complex matrices challenging. This review covers more than 20 years of analytical research on this drug, focusing mainly on pharmaceutical and biological applications. The primary separation techniques discussed are gas chromatography, liquid chromatography, and capillary electrophoresis. The structures of the CAP derivatizing agents as well as a table summarizing various HPLC methods are provided. A discussion of key recent chromatographic and electrophoretic methods for other ACE inhibitors is also present.     

Dispersive liquid-liquid microextraction combined with gas chromatography for extraction and determination of class 1 residual solvents in pharmaceuticals

The present study reports a new method for analyzing class 1 residual solvents (RSs), 1,1-dichloroethene (1,1-DCE), 1,2-dichloroethane (1,2-DCE), 1,1,1-trichloroethane (1,1,1-TCE), carbon tetrachloride (CT), and benzene (Bz), in pharmaceutical products using dispersive liquid-liquid microextraction (DLLME) combined with gas chromatography-flame ionization detection (GC-FID). Unlike common DLLME methods, solvents of high boiling point were selected as dispersive and extraction solvents in order to prevent their chromatographic peaks from overlapping with those of analytes that have short retention times. Therefore N,N-dimethyl formamide (DMF) and 1,2-dibromoethane (1,2-DBE) were chosen as dispersive and extraction solvents, respectively. Analytical parameters of the proposed method were determined and good linearities and broad linear ranges (LRs) were obtained. Taking 500 mg samples, limit of detections for the tested pharmaceuticals were obtained as 0.11, 0.03, 0.05, 0.05, and 0.006 μg g(-1) for CT, 1,1-DCE, 1,2-DCE, 1,1,1-TCE, and Bz, respectively, which are considerably much lower than their permissible limits in pharmaceuticals.     

The analysis of a group of acidic pharmaceuticals, carbamazepine, and potential endocrine disrupting compounds in wastewater irrigated soils by gas chromatography-mass spectrometry

The analysis of pharmaceuticals and potential endocrine disruptors in the environment has rightly concentrated on their presence in wastewaters and possible contamination of receiving bodies, such as groundwaters. However, wastewater is increasingly being reused for irrigation and in order to fully understand the environmental fate of these compounds, reliable methods for their analysis in soil are required, of which there are relatively few available. This article reports a method for a range of acidic pharmaceuticals, carbamazepine, and endocrine disrupting compounds in soils with final analysis by gas chromatography-mass spectrometry. Two soil types (Phaeozom and Leptosol) and three fortification levels were used to validate the method. Recoveries of acidic pharmaceuticals varied between 62 and 102%, carbamazepine from 75 to 118%, and potential endocrine disruptors between 54 and 109%; most recoveries were between 75 and 95% and relative standard deviations were generally less than 10%. Detection limits were between 0.25 and 2.5 ng/g except for phthalates and 4-nonylphenols (25 ng/g). The method was used to analyze soils where untreated wastewaters have been used to irrigate crops for approximately 90 years. Concentrations of acidic pharmaceuticals in the soil were <1 ng/g and potential endocrine disruptors varied from below the limit of detection (estrone, 17β-estradiol, and 17α-ethinylestradiol) to 2079 ng/L (bis-diethylhexyl phthalate). This data indicated that despite the continuous application of the contaminants over many years, concentrations were generally lower than those expected to be contributed by a single irrigation event. Only carbamazepine, at concentrations of 6.48 ng/g (in Phaeozem) and 5.14 ng/g (in Leptosol), showed any evidence of persistence in the soils analyzed.     

Theoretical prediction of the native fluorescence of pharmaceuticals

At present, to search fluorescent compounds or to increase the native fluorescence is an active research line specially and not only with analytical purposes. On some analytical areas and from the early times of applications of fluorescence (mid-fifties) the fluorimeter was defined as the suitable detector for determination of pharmaceuticals and subsequently, this detection mode has been widely applied. Therefore, it is mandatory to develop new strategies to discover or to enhance in a simple way the native fluorescence of organic compounds to increase the number of analytes to be determined by direct fluorescence.In the present paper are studied further applications of a new tool suitable to increase the research in analytical field. Calculations on molecular connectivity and discriminant analysis are applied to a certain number of pharmaceuticals (and some pesticides) on which fluorescence behaviour was observed in an experimental screening or obtained from scientific literature. The screening tests were based on the on-line fluorimetric measurement by using a continuous-flow assembly. The screening comprised pre-selected compounds with different molecular structures. The theoretical predictions agree with the empirical results from the screening test.     

CO2-catalyzed/promoted transformation of organic functional groups

Carbon dioxide is a cheap, non-toxic, abundant chemical and has been widely utilized in organic syntheses. Many new strategies have been developed using CO₂ as a C1 building block and highly utilizable chemicals have been synthesized out of it. On the other hand, CO₂-catalyzed or promoted reactions can also be important from an environmental and scientific point of view. These reactions avoid toxic chemicals, expensive catalysts and often occur under mild reaction conditions. In this review, we would like to draw a summary about organic functional group transformation reactions that are promoted or catalyzed by CO₂.     

简易示波伏安法的研究—药物滴定分析

本文运用简易示波伏安法成功地进行了药物滴定分析,测定了两种新药胃复康及氢溴酸苯甲托品,获得了满意的结果。这种方法克服双池伏安法仪器复杂等缺点,使用一个电解池和一个很简单的线路也可获得示波伏安图。它能部分地扣除充电电流,终点时峰形变化敏锐。