Simple spectrophotometric method for determination of melamine in liquid milks based on green Mannich reaction

Highly Sensitive and Selective Detection Toward Melamine in Dairy Product by Turn-On Fluorescence of Ultrathin Graphitic Carbon Nitride Nanosheet

It is meaningful and promising to develop a practical sensor toward melamine in dairy products with high sensitivity and selectivity. However, complicated composition and environment in milk necessitate stable luminophore as sensor with excellent photophysical properties. Herein, ultrathin graphitic carbon nitride nanosheet (CNNS) is prepared via successive thermal polymerization and acid exfoliation. The photophysical property of CNNS states its strong ultraviolet absorption and intense blue-light emission. Noteworthily, the CNNS could act as a chemo-sensor to detect trace melamine in dairy products. The high stability, eminent sensitivity, powerful selectivity and competitiveness substantiates that this CNNS luminophore is a promising sensor for melamine in dairy products, being of potentially practical value on monitoring milk quality.

Melamine migration measurement through spectrophotometry device and the effect of time and tableware type on it

Melamine is an organic-based chemical material widely used in the production of tableware. Given the adverse effects of melamine on human health, melamine tableware can be a source for its introduction into the human body. The aim of this study was to use a simple method for monitoring the rate of melamine migration from the tableware to food and the effect of time and tableware on this migration. To measure the migration, spectrophotometry was used. The limit of detection (LOD) of the method was 0.2 (μg/ml), which is functional for measuring the rate of migration. The investigation of sample migration of melamine tableware revealed that migration has occurred across all samples. The rate of migration in all samples was less than the standard level of the European Union (30 μg/ml). Statistical analysis indicated that time is an important factor in melamine migration, which significantly increased (p<0.05) in 93% of cases with lengthening the contact time from 30 minutes to 90 minutes. The type of tableware (new or old) and production conditions (standard or non-standard) were found to significantly affect (p<0.001) the rate of migration. Statistical analysis of the results suggested that old tableware increased melamine migration in 41% of cases (p<0.05). Non-standard tableware significantly (p<0.001) increased the rate of migration and thus the effect of non-standard production on melamine tableware was more significant than the age of the tableware.

Data on the levels of Melamine- migration from Melamine- ware products and effect of food type and time on it

Nowadays, Melamine- containers is widely use to because of heat- resistant. Due to the effects of Melamine- on human health, constant and long-term usage of Melamine- containers can be a source of Melamine- exposure to human body. The objective of this research was to measure the levels of Melamine- migration from Melamine- ware-products into foods at different test conditions and Effect of food type and Time on it. Spectrophotometer UV/VIS method was used to detect the limits of Melamine- and the method was based on the in the complex of Melamine- formaldehyde and Uranin (a ketone group).The limit of detection (LOD) of the method was 0.2 (µg/ml) which is functional for measuring. Migration was less than the standard level of European Union (30 µg/ml). In this study, 3% acetic acid, distilled water and 15% ethanol were used as simulants. The results showed the temperature is an important factor in Melamine- migration and in 97% of cases, with increasing temperature from 30 to 90 there is a significant increase (P < 0.05) in Melamine- migration furthermore migration from acidic simulants was more than alcoholic and neutral ones (p < 0.001).

Biomolecule conjugated nanoparticle synthons for detection of food contaminants

This article investigates recent research on a series of photoluminescent nanoparticles (NPs) and supramolecular chemistry at their surface. This in turn prompts the concept of quantum dots supramolecular synthons (QDSS) and foresees the inevitable path towards biomimetics and bioinspired technology. We highlight the methodology how to create QDSS by functional assembly of photoluminescent semiconductors and the surface binding of supramolecular ligands.

Gold nanoparticles-based chemiluminescence resonance energy transfer for ultrasensitive detection of melamine

A turn-on chemiluminescence resonance energy transfer method was fabricated for the determination of melamine by using bis(2,4,6-trichlorophenyl)oxalate-hydrogen peroxide-fluorescein chemiluminescence reaction as a donor and dispersed gold nanoparticles as an acceptor. The chemiluminescence signal of bis(2,4,6-trichlorophenyl)oxalate-hydrogen peroxide-fluorescein reaction decreased significantly in the presence of dispersed gold nanoparticles because the absorption band of dispersed gold nanoparticles perfectly overlapped with the chemiluminescence spectrum. Melamine could induce the aggregation of gold nanoparticles, leading to a dramatic red-shift of the absorption band of dispersed gold nanoparticles. The absorption band of the aggregated gold nanoparticles does not overlap with the chemiluminescence spectrum of the reaction. In such a case, chemiluminescence resonance energy transfer could not happen and the chemiluminescence signal was restored. The procedure allowed the measurement of 3.2×10(-12)-3.2×10(-7) mol/L melamine with a limit of detection of 3×10(-13) mol/L. The method was applied to the determination of melamine in spiked milk samples; with recoveries within the range 94.1-104.2%.

Chemical sensors and biosensors for the detection of melamine

Melamine is an emerging contaminant in milk, infant formula and pet food.