Waters Complete Solution for Dicyandiamide Detection in Dairy

Recently, New Zealand milk and dairy products have been detected to contain low levels of the toxic substance dicyandiamide, the New Zealand government has ordered the ban on the sale of milk products containing dicyandiamide. Domestic dairy producers and government regulators have also begun to establish corresponding analytical methods.

The main difficulties in the detection of dicyandiamide are:

Pretreatment: The method of melamine is completely unsuitable. The dicyandiamide is very polar, and the general small column cannot be retained;

LCMS method: C18 has no retention, HILIC method development is difficult; matrix interference is serious, interference is quantitative and qualitative.

Waters ^® now offers a complete solution that includes sample preparation and LCMS for rapid detection of residual dicyandiamide in dairy products.

- Instruments: Waters ACQUITY UPLC ^® /Xevo ^® TQ-S

- Mass spectrometry conditions:

- Column: BEH Amide column, 2.1 * 150mm

- Mobile phase A : 0.05% aqueous acetic acid solution   

- Mobile phase B : 0.05% acetic acid acetonitrile

- flow rate : 0.3 mL/min; gradient elution

- Column temperature : 30 ° C

Standard 5ppb mass spectrum

Solid phase extraction conditions:

Take 1g milk powder and 10mL 1% trichloroacetic acid to dissolve and precipitate protein, centrifuge at 12,000 rpm for 10min; take 2mL supernatant and load onto Sep-Pak AC2 cartridge (Sep-pak AC2 with 30mL reservoir, wat011390) The method recovery rate is 91%.

Matrix spiked (8 ppb) post-column mass spectrum

Conclusion: The dairy matrix is ​​more complex. The Sep-Pak ^® AC2 solid phase extraction column can purify and enrich the sample. The dicyandiamide polar molecule is very polar, and the traditional C18 column cannot be retained. Waters' BEH Amide The column is a propylamide stationary phase, which allows dicyandiamide to have good retention and peak shape in the hydrophilic interaction chromatography HILIC mode. At the same time, ACQUITY UPLC combined with Xevo TQ-S MS can achieve fast and highly sensitive analysis results.

Ordering information:

For more information, please contact Waters Application Technology Specialist:
Ji Yinghua 021-61562612; Ding Juanjuan 021-61562604.