Subpicogram Determination of Melamine in Milk Products Using a Luminol−Myoglobin Chemiluminescence System

Abstract

A sensitive chemiluminescence method based on a luminol-myoglobin system is proposed for the determination of melamine in milk products. It was found that the mixed solutions of melamine and myoglobin could react to form a complex on line, which could greatly inhibit the chemiluminescence intensity generated from the reaction between luminol and myoglobin. The decrease in chemiluminescence intensity was proportional to the concentration of melamine, giving a calibration graph linear over the concentration from 10 pg mL(-1) to 50 ng mL(-1) (R(2) = 0.9988) with a detection limit of 3 pg mL(-1) (3sigma). At a flow rate of 2.0 mL min(-1), one analysis cycle, including sampling and washing, could be accomplished in 20 s with a relative standard deviation of <4.0%. The proposed method was applied successfully to the determination of melamine in milk products, and the recovery was from 93.4 to 106.5%. The possible mechanism of luminol-myoglobin-melamine reaction is given.

Simultaneous determination of melamine and related compounds by hydrophilic interaction liquid chromatography–electrospray mass spectrometry

“…It is very rich in nitrogen (67% by mass) and has been found in milk products and animal feed, where it possibly has been added to give a false impression of high protein content (http:// www.scientificamerican.com/article.cfm?id 5 protein-pretense (accessed on October 20, 2008); http://www.who.int/foodsafety/ fs_management/Melamine.pdf (accessed on October 8, 2008)) [1][2][3][4][5]. Melamine can produce ammeline, ammelide, cyanuric acid by hydrolysis in strong acid or strong base solution.…”

Determination of the Binding Parameters between Proteins and Luminol by Chemiluminescence Using Flow Injection Technique

“…In our previous study, it was found that BSA, LYS, MB, and CAT can accelerate the electrons transferring rate of excited 3-aminophthalate leading to enhancement of CL intensity from luminol [30][31][32][33]. However, no comprehensive …”

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

“…Although these instrumental methods offer several advantages, such as high sensitivity, high throughput and high potential for melamine monitoring, they necessarily require various extraction and preparation techniques. Aside from chromatographic methods, other analytical approaches, such as enzyme immunoassay couple with HPLCdiode array detection [11], capillary electrophoresis coupled with ESI-MS [12], electrochemical sensor and/or chemiluminescence [13] have also been developed. However, the methods mentioned above are not widely used in basic analytical laboratories because they require complicated sample preparation and more expensive instrumentation, and they are more time consuming.…”