Food Testing Trace-Level Analysis of Chlorates in Milk and Infant Formula

This article highlights an 8-minute analytical method for the quantification of chlorate and perchlorate in milk and infant formula. The method uses an Agilent 1290 Infinity II LC and Ultivo triple quadrupole LC/MS (LC/TQ) with an AJS source. The Ultivo LC/TQ was designed to save laboratory space, while maintaining the performance and robustness required for high-throughput analyses. Chlorate and perchlorate have maximum residue limits (MRLs) of 10 μg/kg in milk and infant formula, as defined by the European Commission. This method achieved accurate quantitation at one tenth the level of the MRL. The method precision was <10 % (%RSD) at the lowest level of quantitation with n = 10.

Chlorate and perchlorate residues have become a growing concern with agriculturally produced foods, such as dairy products, fruits, and vegetables. The presence of chlorate and perchlorate in dairy products can occur when chlorinated water and chlorine-containing detergents are used for cleaning and sanitizing process equipment at both farm and processor level. Perchlorate can be found in agricultural-based foods as it is heavily used in the production of nitrate-based fertilizers. Disinfection of milk processing equipment is important for the prevention of food-borne diseases and the use of nitrite-based fertilizers is important in crop yields, therefore, widespread use of chlorate and perchlorate for sanitation in industrial food production processes have been observed. The maximum residue level (MRL) of chlorate and perchlorate is set at 0.01 mg/kg in milk and infant formula, and can accurately quantify down to 1/10 MRL. The Ultivo triple quadrupole LC/MS is an appropriate system for these measurements.

Note that chlorate and perchlorate contamination from consumables in the analytical system should be checked before tests begin. Nylon or regenerated cellulose (RC) filters and plastic tubes can be significant sources of perchlorate.