Química Analítica : materiales docentes : grado de Ingeniería Química, 2º curso

El capítulo 1 está dedicado al proceso analítico y a las propiedades analíticas que afectan a la calidad del resultado y del procedimiento de análisis químico. El capítulo 2 describe el muestreo y diferentes procesos de preparación de muestra. El capítulo 3 trata de los diferentes métodos volumétricos de análisis, incluyendo las valoraciones ácido-base, de formación de complejos, en medio heterogéneo y de oxidaciónreducción. Los tres capítulos siguientes están relacionados con los métodos espectroscópicos. El capítulo 4 es un tema de introducción a los métodos instrumentales en el que se describen los métodos de calibración, las fuentes de ruido y las características, especificaciones y clasificación de los analizadores de procesos y incluyendo el analizador continuo de flujo no segmentado. El capítulo 5 describe los métodos espectroscópicos en UV-Visible e IR, sus principios básicos, IV Prólogo componentes, función y requerimientos. El capítulo 6 está dedicado a los métodos espectroscópicos de análisis molecular, fundamento, aplicaciones y manejo de instrumentos. En el capítulo 7 se describe las características generales y aplicaciones de las técnicas de espectroscopía atómica o elemental. El capítulo 8 se dedica a las generalidades de la cromatografía, incluyendo el fundamento y aplicaciones de la cromatografía de gases y la detección por espectrometría de masas. El capítulo 9 describe los aspectos básicos e instrumentación de la cromatografía de líquidos de alta resolución y su acoplamiento a espectrometría de masas. Finalmente, en el capítulo 10 se describe el fundamento clasificación y aplicaciones de los sensores electroanalíticos.En el marco del Espacio Europeo de Educación Superior (EEES), cobra especial relevancia el impacto de las Tecnologías de la Información y la Comunicación (TICs) con posibilidades tanto para la elaboración del conocimento como para su adquisición y transmisión, mediante métodos pedagógicos más innovadores, adcesibles e interactivos que se adapten a los diferentes tipos de estudiantes. El acceso a las redes de la información dotan al docente y al alumnado de poderosas herramientas que abren un gran abanico de posibilidades metodológicas. Siguiendo esta línea, el ámbito de aplicación de este material docente corresponde a la materia de enseñanza-aprendizaje de “Química Analítica” de segundo curso (primer semestre) de la titulación de Grado en Ingeniería Química impartida en la Escuela Técnica Superior de Ingeniería (ETSE) de la Universidad de Santiago de Compostela

Ultrasound-assisted enzymatic indirect determination of total 3-monochloropropane-1,2-diol esters in canned fish oil fraction

A novel, fast, and cost-effective indirect enzymatic method was successfully developed to assess the total 3-monochloropropane-1,2-diol (3-MCPD) in canned food's oil fraction by the action of Burkholderia cepacia lipase. The total 3-MCPD were derivatized with n-Heptafluorobutyrylimidazole (HFBI) for GC–MS analysis during dispersive liquid–liquid microextraction (DLLME). An asymmetrical 2213//8 screening design was used to study the influence of critical factors on the method's effectiveness. The analytical features of the proposed method were assessed following Food and Drug Administration (FDA) guidelines using extra virgin olive oil (EVOO) as a blank sample. Outstanding results were achieved in terms of linearity (r2 = 0.9995), sensitivity, precision (2.1 % to 10.4 % RSD), and accuracy (98.7 % ≤ recovery ≤ 101.9 %). Method efficacy was tested by comparing the results of 10 edible oils for total 3-MCPD with those reported in previous works. A total of 41 samples were analyzed. The lowest 3-MCPD content was found in samples of albacore canned in EVOO oil, while the highest amounts were found in albacore, mackerel, and Atlantic saury samples, all preserved in refined sunflower oilThis work was supported by the Spanish Ministry of Science, Innovation, and Universities (Project RTI2018‐096450‐B‐I00) and FEDER fundsS

Determination of synthetic opioids in oral fluid samples using fabric phase sorptive extraction and gas chromatography-mass spectrometry

New psychoactive substances (NPS) continue to emerge in the drug market every year, becoming a global threat to public health and safety. These compounds are mostly synthetic cannabinoids and designer cathinones. However, synthetic opioids have appeared on the recreational drug markets in recent years, particularly fentanyl and its derivatives (“fentanyls”). Fentanyl and its analogs are related to harmful intoxications and an increase in opioid-related mortality in many countries, such as in the United States and Europe in the last years. Taking the drug related global crisis into consideration, this work developed and validated an effective and sensitive method based on fabric phase sorptive extraction (FPSE) followed by gas chromatography-mass spectrometry (GC-MS) for the simultaneous determination of 11 fentanyl analogs in oral fluid samples. The extraction was carried out using a sol-gel Carbowax 20 M sorbent immobilized on 100% cellulose fabric substrate and using ethyl acetate as the desorption solvent. The limits of detection (LODs) and quantification (LOQs) ranged from 1 to 15 ng mL−1 and 5 to 50 ng mL−1, respectively. Intra-day and inter-day precision were found within 8.2% and 8.6%, respectively, while accuracy ranged from -5.5 to 9.1%, in accordance with the established criteria. The absolute recovery values were in the range of 94.5%–109.1%. The validated method demonstrated its great potential to detect and quantify fentanyl analogs in possible forensic work and off-site analysis in road traffic casesThis work was supported by the Spanish Ministry of Science, Innovation, and Universities (Project RTI2018‐096450‐B‐I00) and FEDER fundsS

Development of a QuEChERS method for simultaneous analysis of 3-Monochloropropane-1,2-diol monoesters and Glycidyl esters in edible oils and margarine by LC-APCI-MS/MS

A simple, fast and effective direct method based on HPLC-APCI-QqQ-MS/MS has been developed to simultaneously determine four 3-monochloropropane-1,2-diol monoesters (3-MCPDE) esterified with palmitic, linoleic, stearic, and oleic acid, and two glycidyl esters (GE) with palmitic and oleic acid in margarine and olive oil using a QuEChERS approach. Factors affecting the efficiency of the extraction process were assessed, including type and amount of salt, extraction solvent, test portion amount, and clean-up sorbent. The analytical method was validated according to Food and Drug Administration (FDA) guidelines using matrix-matched calibration with internal standards and showed good results in terms of linearity (r2 > 0.9992), accuracy (80<Recovery<120%), and precision (RSD<15%). The method was successfully applied for the first time to 11 margarine samples for simultaneous analysis of 3-MCPDE and GEThis work was supported by the Spanish Ministry of Science, Innovation, and Universities (Project RTI2018‐096450‐B‐I00) and FEDER fundsS

GC–MS determination of malondialdehyde, acrolein, and 4-hydroxy-2-nonenal by ultrasound-assisted dispersive liquid-liquid microextraction in beverages

A new, fast, simple, and effective ultrasound-assisted dispersive liquid-liquid microextraction procedure (UA-DLLME) for the gas chromatography-mass spectrometry (GC–MS) determination of malondialdehyde, acrolein, and 4-hydroxy-2-nonenal in beverages was successfully developed. 2,4-Dinitrophenylhydrazine derivatization was performed during extraction. An asymmetrical 3541//18 screening design and a central composite surface response design were used to investigate the influence of the most critical factors during the extraction process (ultrasound time and temperature, extraction and disperser solvents volumes, salt addition, and derivatization reagent concentration). According to FDA guidelines, the method was validated, achieving good linearities with r2 ≥ 0.9982, recoveries between 94.0 and 102.4%, and reproducibility with RSD lower than 4.5%. The method was applied to simultaneously determine the compounds in 60 different beverage samples, including beer, coffee, black tea, and fruit juices. The presence of secondary lipid oxidation products is demonstrated in beverages with a strong roasting process or oxidationThis work was supported by the Spanish Ministry of Science, Innovation, and Universities (Project RTI2018‐096450‐B‐I00) and FEDER fundsS