Over the past several decades, green chemistry has gained prominence in chemistry education. However, the development of green chemistry curricula has not reached all levels of education equally, focusing mainly on elective and upper division courses. We deliberately focused our green chemistry curriculum redesign on a high enrollment introductory general chemistry laboratory course at the University of California, Berkeley. We developed over 30 new experiments that introduced students to green chemistry concepts and applications, while maintaining canonical general chemistry learning goals. The context of the curriculum and required course assignments encouraged students to use green chemistry principles to explore and solve real-world problems. After completing this redesigned course, we hypothesized that students would value green chemistry and feel more confident in their green chemistry knowledge. We developed new methods to measure students’ attitudes toward and understanding of green chemistry as a system instead of isolated reactions or processes. These assessments allowed us to better understand both the progression and limitations in student green chemistry and systems-thinking. Since over 2000 students complete the laboratory course each year, we used a combination of fixed response items and free response items from online surveys and in-class assignments and exams. This approach allowed efficient assessment of thousands of students, while still gaining valuable and nuanced views of student understanding and attitudes. These assessments indicated that the new general chemistry laboratory curriculum succeeded in providing an environment in which students learned green chemistry concepts and realized that chemistry has connections to their future courses and professions.

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In this undergraduate analytical chemistry experiment, students quantitatively assess the antibacterial activity of essential oils found in thyme leaves (Thymus vulgaris) in an authentic, research-like environment. This multiweek experiment aims to instill green chemistry principles as intrinsic to chemical problem solving. Students progress through various techniques including extraction, chromatography (TLC and HPLC), culturing bacteria, and disk diffusion via a process of guided exploration that emphasizes green experimental design. Approximately 600 undergraduate students carried out the experiment and self-reported substantial learning gains.

A rapid screening assay (9 min/sample) has been developed and validated for the detection of deoxynivalenol in durum wheat, wheat products, and maize-based baby foods using an SPR biosensor. Through a single laboratory validation, the limits of detection (LOD) for wheat, wheat-based breakfast cereal, and maize-based baby food were 57, 9, and 6 μg/kg, respectively. Intra-assay and interassay precisions were calculated for each matrix at the maximum and half-maximum European Union regulatory limits and expressed as the coefficient of variation (CV). All CVs fell below 10% with the exception of the between-run CV for breakfast cereal. Recoveries at the concentrations tested ranged from 92 to 115% for all matrices. Action limits of 161, 348, and 1378 μg/kg were calculated for baby food, wheat-based breakfast cereal, and wheat, respectively, and the linear range of the assay was determined as 250-2000 μg/kg.

INTRODUCCION El desarrollo de nuevos antihelmínticos para el control del parasitismo en las diferentes especies domésti-cas ha sido el área donde la investigación farmacéutica ha experimentado la mayor expansión durante los últi-mos años. El amplio uso de estos compuestos y la nece-sidad de asegurar la calidad e inocuidad de los alimentos provenientes de animales tratados con antihelmínticos, ha llevado a desarrollar técnicas y metodologías cada vez más sensibles y exactas para la determinación de estos fármacos en diferentes tejidos animales. La cromatografía líquida de alta eficiencia (HPLC) en fase reversa repre-senta una técnica analítica confiable y de alta precisión, mediante la cual es posible estudiar el perfil de depleción de residuos de dos antiparasitarios de acción complemen-taria como son abamectina (ABM) y triclabendazol (TCBZ). ABM es una lactona macrocíclica perteneciente al grupo de las avermectinas (AVM), que son una serie de compuestos naturales y semisintéticos, que poseen un mecanismo de acción común, con potente actividad antihelmíntica y endectocida (McKellar y Benchaoui 1996). El TCBZ (5-cloro-6-(2,3-diclorofenoxi)-2-metil-tiobencimidazol) es un bencimidazol halogenado que posee elevada actividad frente a estados inmaduros y adultos de Fasciola hepática, habiendo demostrado una elevada eficacia fasciolicida en ovinos, caprinos y bovi-nos (Misra y col 1987, Wolff y col 1983). Esta acción se asocia principalmente con el metabolito activo triclabendazol sulfóxido (TCBZSO), ya que el fármaco original TCBZ es rápidamente metabolizado en el híga-do hacia sulfóxido y posteriormente a sulfona (TCBZSO 2), el cual es inactivo (Hennessy y col 1987). En las prácticas de manejo intensivo en la crianza de animales, la asociación de fármacos antiparasitarios para lograr un espectro antihelmíntico más amplio, es frecuen-temente utilizada por los ganaderos tanto para tratamien-tos preventivos como curativos de las parasitosis. Así la asociación de ABM y TCBZ es una formulación comer-cial que ha sido diseñada para entregar una protección adecuada contra nemátodos, artrópodos y tremátodos. Por constituir una formulación farmacéutica de apa-rición reciente en el mercado nacional, no existen ante-cedentes acerca de sus concentraciones residuales en te-jidos de consumo para estos fármacos cuando se admi-nistran asociados, por lo que el objetivo de este estudio fue determinar la presencia y persistencia de residuos de ABM y TCBZ o sus principales metabolitos en tejidos comestibles, tales como músculo, hígado, riñón y grasa, Determinación de residuos de abamectina-triclabendazol en tejidos bovinos # SUMMARY Abamectin (ABM) and Triclabendazole (TCBZ) are two potent antiparasitic drugs that differ in their chemical structure and spectrum of action. In this study, a sensitive HPLC-method was developed and validated to determine ABM and TCBZ residues in bovine edible tissues, and the pattern of tissue depletion of an oral formulation containing the association abamectin (ABM)-triclabendazole (TCBZ) was characterized...