Mar. 27, 2018
Maximum residue limits (MRLs) of herbicide flumioxazin established by the Pest Control Products Act and Health Canada’s Pest Management Regulatory Agency (PMRA) have been adopted. They entered into force on March 1, 2018 for caneberries, broccoli, peppermint tops and spearmint tops, imported and offered for sale.
Flumioxazin is well-known as an herbicide belonging to a group of Benzoxazinones. It has been widely used to remove weeds from fields of soybean, peanut, orchard fruits, and crops. The accumulation of this compound in plants will block chlorophyll synthesis. Flumioxazin is not toxic for humans but to fish it is slightly to moderately toxic.
To ensure food safety for consumers, the European Union (EU), Japan, and United States already have their own MRLs for flumioxazin. Canada’s MRLs are more recent and have now been established and adopted by the World Trade Organization (WTO). The new MRLs and affected crops are shown in Table 1 
||Parts per million
||Leaf Petioles; broccoli, peppermint tops, spearmint tops
Traditionally, a diverse array of sample preparation methods such as solvent extraction, soxhlet extraction, microwave-assisted solvent extraction (MASE), ultrasonic solvent extraction (USE), supercritical fluid extraction (SFE), and matrix solid phase dispersion (MSPD) have been used to determine pesticide residues in crops. These methods use large quantities of organic solvents, are tedious, time-consuming, and lack sufficient selectivity. Recently, the QuEChERS method (quick, easy, cheap, effective, rugged and safe) has been introduced to solve the problem and enable the simultaneous extraction of multi-class herbicides 
. Highly sensitive and selective instruments, including gas and liquid chromatography tandem mass spectrometry (GC-MS/MS and LC-MS/MS), are required to meet the legislation’s requirements.
What do the changes mean?
This update has the potential to affect agricultural producers, food manufacturers, and pesticide manufacturers. Residues of flumioxazin on food products destined for Canada must not be found to exceed the MRLs. In order to achieve compliance with food safety regulations, food producer should seek professional advice.