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Currently, sample preparation is the most laborious part of the analytical process, requiring the most time and being susceptible to the most errors. In this context, numerous investigations have focused on the miniaturization of these techniques to reduce work time, costs, and errors. In this regard, microextraction by packed sorbent (MEPS) is a simple, fast, and robust sample preparation technique suitable for easy automation in several analytical systems and is applied to a wide variety of samples. Antibiotics are among the most commonly used drugs; however, their extensive and inappropriate use has garnered significant attention in the environment, human health, and food safety. This brief review is intended to provide an overview of recently reported antibiotic extraction methods based on MEPS, with a special interest in those applied to the analysis of biological, environmental, and food samples. In addition, the sample pretreatment step before extraction by the MEPS device was highlighted, as was the description of the sample-related steps within the MEPS procedure, such as extraction, washing, and elution.

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The aim of the paper is to determine the effect of corruption, using human development index (HDI), and its sub-indices: education, life expectancy and gross national income in 135 developed and developing countries over the period of 2005–2021. A dynamic estimation (sys-GMM) method was employed and the transformation of Prais-Winsten with corrected standard errors for correlated panels (PCSE) and GMM were used for robustness check. The findings show that corruption, in any of the indices, serves as a human development constraint for both the overall country sample, and for the countries grouped by income level. An interesting result is that the education index in the lower-income countries is more sensitive to corruption, while corruption affects the income index to a greater extent in the higher-income countries. The analysis also confirms that democracy, economic freedom, investment, social public spending, as well as, globalisation and information and communication technologies are influencing factors of HDI. [ABSTRACT FROM AUTHOR]

Recently, pharmaceutical and personal care products (PPCPs) have received considerable attention because of their increasing use. Analysis of PPCPs presents a significant analytical challenge, with high-performance liquid chromatography (HPLC) in reversed-phase mode, as the most widely used analytical technique. To facilitate the optimization of the procedures that are applied in the early stages of sample preparation, a simple and fast HPLC method is proposed in this work for the separation of some PPCPs with a wide range of hydrophilicity. Two columns were evaluated (Atlantis dC18 and Discovery HS F5); as for mobile phases: a formate buffer (40 mmol L−1, pH 4) and methanol were tested in a gradient mode. The fluorinated column allowed better separation in a shorter time and better resolution for all analytes (Rs > 1). The proposed method delivered good performance for the tracing of PPCPs and is a suitable alternative to traditional C18-based HPLC methods.

Solid-phase microextraction (SPME) is a sample preparation technique with many applications that is being continuously developed. In this technique, the type of fiber coating plays a crucial role for extraction efficiency. Currently available commercial coatings have certain drawbacks that have been overcome by the development of new coatings based on novel materials; these have improved the efficiency of extraction, selectivity and stability of commercial coatings. Pharmaceutical and personal care products (PPCPs) are one of the most important groups of emerging contaminants; however, some studies suggest that these compounds can cause adverse health effects. No official monitoring protocols for these compounds are currently available, so the establishment of analytical methods that allow their determination in environmental samples is required. The complexity of environmental samples together with the low concentration levels of these compounds makes necessary the use of sample preparation techniques capable of removing interferences, as well as preconcentrated analytes, and SPME is a very promising alternative to achieve this. This review describes the recent developments in SPME with classical and novel coatings and its applications for PPCP determination in environmental samples.

Photosensitization of proteins mediated by chromophores is a mechanism commonly employed by nature and mimicked in a broad array of laboratory research and applications. Nature has evolved specialized complexes of proteins and photosensitizers (PS) that assemble to form photoreceptor proteins (PRP). These are used by many organisms in diverse processes, such as energy conversion, protection against photodamage, etc. The same concept has been used in laboratory settings for many applications, such as the stimulation of neurons or the selective depletion of proteins in a signaling pathway. A key issue in laboratory settings has been the relationship between the photooxidation of proteins and conformational changes in host proteins. For several years, we have been interested in creating non-native PRP using porphyrin PS. In this study, we investigated the self-assembled complex between zinc protoporphyrin IX (ZnPPIX) and bovine β-lactoglobulin (BLG) as a model of non-native PRP. Since BLG undergoes a significant conformational transition near physiological pH, the study was carried out at acidic (pH 5) and alkaline (pH 9) conditions where the two conformations are respectively prevalent. We employed a series of steady-state and time-resolved optical spectroscopies as well as gel electrophoresis to experimentally characterize the photosensitization mechanisms and their effect on the host protein. Our results show that ZnPPIX prompts light-dependent modifications of BLG, which appear to be much more significant at alkaline pH. The modifications seem to be driven by photooxidation of amino acid residues that do not lead to the formation of cross-links or protein fragmentation. [ABSTRACT FROM AUTHOR]

Mexico, among the OECD countries, is the country with the greatest difference in income between rich and poor. This situation has been accompanied by high levels of perception of corruption. The goal is to show that corruption and income inequality are correlated. The estimates are affected by the endogeneity problem caused by the two-way causality of corruption and income inequality, and by measurement errors of the variable used for corruption. Therefore, the method of simultaneous equations is used and it is estimated by error-component two stage least squares (EC2SLS), alternatively the Generalized Method of Moments (GMM) and sys-GMM are used, to analyze the sensitivity of the results. Robust evidence is found of a positive relationship between corruption and income inequality in Mexico in the period 2010-2020. [ABSTRACT FROM AUTHOR]

The analysis of phenolic acids (PAs) is of great importance, because they are frequently present in natural products and their derivatives, and these compounds also have multiple beneficial effects to human health. This work is focusing on the separation of seven PAs (caffeic acid, coumaric acid, gallic acid, ferulic acid, protocatechuic acid, sinapic acid, and syringic acid), in a reversed-phase liquid chromatographic (RP-HPLC) isocratic method using a hydrophilic deep eutectic solvent (DES) as a mobile phase additive. The analysis was carried out with a diode array detector. The used DES was composed by choline chloride and glycerol, and it was characterized by infrared spectroscopy. The combination of choline chloride:glycerol (1:4) added at 0.25% to mobile phase composed of 0.15% formic acid aqueous solution and methanol (80:20), showed the best separation for target analytes. The new proposed method was validated, and results indicated that the proposed method is linear, selective for almost all analytes, provided high sensitivity with limit of detection ranges from 0.009 to 0.023 mg mL−1, and has satisfactory precision and accuracy, with values of relative standard deviation of 0.24–2.65% and recoveries of 97.97–109%, respectively. Additionally, this method was successfully applied to simultaneous determination of phenolic acids in three kinds of samples of powder to prepare lemon flavour drink enriched with black tea extract. [ABSTRACT FROM AUTHOR]

En este trabajo se analizo la economia de la produccion de maiz amarillo (Zea mayz) en el valle del medio y bajo rio Sinu, en el departamento de Cordoba (Colombia), con informacion procedente de una encuesta a 1.417 agricultores, realizada en el semestre A de 2001. Los resultados indican que la mayor oferta proviene de los agricultores medianos y grandes; sin embargo, en el analisis de costos minimos, los agricultores pequenos resultan ser mas eficientes economicamente que las explotaciones de tamano superior. Con la utilizacion de herramientas estadisticas y econometricas, los resultados indican que la produccion de maiz en Cordoba presenta rendimientos decrecientes de escala; las productividades marginales del gasto obtenidas senalan la conveniencia de reducir gastos totales, en especial en semillas y control de plagas, y aumentarlo en control de malezas.