Using the Melamine Contamination of Foods To Enhance the Chemistry Classroom

Kimbrough, Doris R.; Jensen, Anna Chick

doi:10.1021/ed800174h

Cited by 14 publications

(12 citation statements)

References 15 publications

(14 reference statements)

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“…In recent years, however, melamine has been deliberately added to dairy products and pet food to raise the apparent crude protein value in some developing countries due to its high nitrogen level (about 66% by mass), because the Kjeldahl method, which is commonly employed to quantify the crude protein content in foods, cannot differentiate it from protein molecules. 1 Although melamine has slight acute toxicity, unfortunately, it will result in the renal failure and even death of children or pets after a long-term intake of melamine-tainted food owing to the formation of insoluble melamine cyanurate crystals in the kidneys. 2,3 Currently, the available techniques for melamine detection such as gas chromatography (GC), liquid chromatography (LC) or capillary electrophoresis (CE) coupled with UV or MS detector have high sensitivity; 4-10 nevertheless, many of them are generally time-consuming and require relatively expensive and complicated instruments.…”

Section: Introductionmentioning

confidence: 99%

Sensitive turn-on fluorescent detection of melamine based on fluorescence resonance energy transfer

Guo

Zhong

et al. 2011

Analyst

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We here report a novel fluorescent method for the detection of melamine based on the high fluorescence quenching ability of gold nanoparticles. The fluorescence was significantly quenched via fluorescence resonance energy transfer when fluorescein molecules were attached to the surface of gold nanoparticles by electrostatic interaction. Upon addition of melamine, the fluorescence was enhanced due to the competitive adsorption of gold nanoparticles between melamine and fluorescein. Under the optimum conditions, the fluorescence enhancement efficiency [(I-I(0))/I(0)] showed a linear relationship with the concentration of melamine in the range of 1.0 × 10(-7) mol L(-1)~4.0 × 10(-6) mol L(-1), and the detection limit was calculated to be 1.0 × 10(-9) mol L(-1). The proposed method showed several advantages such as high sensitivity, short analysis time, low cost and ease of operation.

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Section: Introductionmentioning

confidence: 99%

Sensitive turn-on fluorescent detection of melamine based on fluorescence resonance energy transfer

Guo

Zhong

et al. 2011

Analyst

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“…Research on teaching science has also found opportunities for students to use food in classroom examples. Some examples include studying the properties of selfheating food (Oliver-Hoyo, Pinto, & Llorens-Molina, 2009) or food contamination (Kimbrough & Jensen, 2010). In my work with preservice teachers, they often designed lessons for teaching fractions that involved real or fake food.…”

Section: Extant Appearances Of Food In Classroom Settingsmentioning

confidence: 99%

Theorizing Food Sharing Practices in a Junior High Classroom

Rice¹

2013

ucbgse_bre

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This reflective essay analyzes interactions where food was shared between a teacher and her junior high school students. The author describes the official uses of food in junior high school classrooms and in educational contexts in general. The author then theorizes these interactions, suggesting other semiotic, dialogic, and culturally encoded possibilities for interpreting food exchanges between teachers and students. These possibilities are contextualized using several stories that demonstrate socially grounded interpretations of food use, which contrast with typical notions of how food operates in educational contexts. The implications of these stories raise questions about how relationships are built and maintained in classrooms, what happens in reality when items are banned at school, and what possibilities exist for teachers as they approach classroom interactions in more strategic ways.

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“…DCD molecules show similar characteristics to protein molecules in traditional Kjeldahl protein analysis, which is usually employed to quantify the crude protein content in foods, and the traditional Kjeldahl method cannot differentiate it from protein molecules. 3 Therefore, it is very important to develop a simple and sensitive analytical method to identify and quantify DCD.…”

Section: Introductionmentioning

confidence: 99%

3-Aminophenylboronic acid-functionalized CuInS₂quantum dots as a near-infrared fluorescence probe for the detection of dicyandiamide

Liu

Pang

Huang

2014

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In this paper, a simple and highly selective method for the determination of dicyandiamide (DCD) was developed based on the fluorescence quenching of functionalized CuInS2 quantum dots (QDs). Water-soluble CuInS2 QDs, capped by mercaptopropionic acid, were directly synthesized in aqueous solution and then covalently linked to 3-aminophenylboronic acid molecules to form the 3-aminophenylboronic acid-functionalized CuInS2 QDs (F-CuInS2 QDs) that had a fairly symmetric fluorescence emission centered at 736 nm. Based on the cyclization of the guanidine group of DCD with 2,3-butanedione and 3-aminophenylboronic acid, the fluorescence of the F-CuInS2 QDs is quenched by DCD in the presence of 2,3-butanedione. This method effectively distinguishes DCD from other amino acids and nitrogen pollutants, such as melamine, in real milk samples. Under optimum conditions, there was a good linear relationship between the fluorescence intensity of F-CuInS2 QDs and the concentration of DCD in the range of 2.0 × 10(-6) to 2.0 × 10(-3) mol L(-1), with a detection limit of 0.6 μmol L(-1).

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Using the Melamine Contamination of Foods To Enhance the Chemistry Classroom

Cited by 14 publications

References 15 publications

Sensitive turn-on fluorescent detection of melamine based on fluorescence resonance energy transfer

Sensitive turn-on fluorescent detection of melamine based on fluorescence resonance energy transfer

Theorizing Food Sharing Practices in a Junior High Classroom

3-Aminophenylboronic acid-functionalized CuInS₂quantum dots as a near-infrared fluorescence probe for the detection of dicyandiamide

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Using the Melamine Contamination of Foods To Enhance the Chemistry Classroom

Cited by 14 publications

References 15 publications

Sensitive turn-on fluorescent detection of melamine based on fluorescence resonance energy transfer

Sensitive turn-on fluorescent detection of melamine based on fluorescence resonance energy transfer

Theorizing Food Sharing Practices in a Junior High Classroom

3-Aminophenylboronic acid-functionalized CuInS2quantum dots as a near-infrared fluorescence probe for the detection of dicyandiamide

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Product

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3-Aminophenylboronic acid-functionalized CuInS₂quantum dots as a near-infrared fluorescence probe for the detection of dicyandiamide