This rapid method uses the Agilent 6410 Triple Quadrupole (QQQ) with a cation ion exchange column for the liquid chromatography tandem mass spectrometry (LC/MS/MS) analysis of dairy products for melamine. Milk and milk products are prepared with a simple SPE cleanup method employing the new Agilent SampliQ SCX cartridge. The residue is quantified in the multiple reaction monitoring (MRM ) mode. The selectivity of the QQQ can easily eliminate any matrix interferences that may occur in the separation and provide excellent response. The method provides good results with respect to precision, repeatability, and spiked recovery. The recov- ery of 80 ppb and 50 ppb melamine spikes in milk powder using the external stan- dard calculation is 62.5 and 83.4 percent, respectively, and the RSD is less than 3 percent.
This document details a method for the rapid screening and confirmation of melamine residues in milk and milk products using Liquid Chromatography Tandem Mass Spectrometry (LC/MS/MS). The method utilizes the Agilent 6410 Triple Quadrupole mass spectrometer coupled with a ZORBAX 300SCX ion-exchange column and SampliQ SCX SPE cartridges for sample cleanup. The procedure involves a simple solid-phase extraction (SPE) cleanup followed by quantification in multiple reaction monitoring (MRM) mode, which provides excellent selectivity to eliminate matrix interferences found in dairy products.
The application note presents experimental data demonstrating the method's sensitivity, linearity, repeatability, and recovery rates. Results indicate a limit of detection (LOD) of 0.2 ppb and a limit of quantitation (LOQ) of 0.5 ppb. The method achieves good precision with relative standard deviations (RSD) of less than 3 percent for spiked samples and provides reliable confirmation of positive screening results obtained via less selective methods like LC/UV.
| Flow rate | 0.2 mL/min |
|---|---|
| Column Temperature | 40°C |
| Polarity | Positive |
| Dry gas temperature | 350 °C |
| LOD | 0.2 ppb |
| LOQ | 0.5 ppb |
The method uses the Agilent 6410 Triple Quadrupole mass spectrometer.
The limit of detection (LOD) is 0.2 ppb.
No, the method requires no derivatization.