Issue 4, 2010

Direct analysis of melamine in complex matrices using a handheld mass spectrometer

Abstract

A low temperature plasma ambient ionization source, coupled to a portable mass spectrometer (Mini 10.5), is used for the determination of melamine contamination in whole milk and related materials. Thermally assisted desorption and ionization of the analyte was achieved with the plasma probe. The small size, low power consumption and capability for direct sampling without pretreatment makes plasma ionization an appropriate ionization method for use with a handheld mass spectrometer. The standard discontinuous atmospheric pressure interface used to connect atmospheric pressure ion sources to mass spectrometers (Gao et al., Anal. Chem., 2008, 80, 4026–4032) was modified by using supplementary pumping to increase the ion transfer efficiency. Whole milk, fish, milk powder and other complex matrices spiked with melamine were placed on glass slides close to the vacuum inlet and analyzed without sample pretreatment. Quantitation in complex matrices was achieved using MS/MS of protonated melamine m/z 127 to yield the characteristic fragment ion of m/z 85. Analysis rates of two samples per minute, levels of melamine as low as 250 ng/mL in whole milk (below the regulatory level in the US of 1 ppm (1 μg/mL) or the European level of 2.5 ppm (μg/mL)), a linear dynamic range of 0.5–50 μg/mL and a relative standard deviation of ca. 7.6–16.2% were achieved. The importance of melamine to public health and the prior lack of a rapid, sensitive and yet highly specific field analysis method add to the relevance of this study.

Graphical abstract: Direct analysis of melamine in complex matrices using a handheld mass spectrometer

Supplementary files

Article information

Article type
Paper
Submitted
09 Nov 2009
Accepted
09 Dec 2009
First published
24 Dec 2009

Analyst, 2010,135, 705-711

Direct analysis of melamine in complex matrices using a handheld mass spectrometer

G. Huang, W. Xu, M. A. Visbal-Onufrak, Z. Ouyang and R. G. Cooks, Analyst, 2010, 135, 705 DOI: 10.1039/B923427F

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements