Monday, June 9, 2008

How to STORE the Brominated diphenyl ethers for GC/MS

Brominated diphenyl ethers in water, soil, sediment, and tissue by GC-MS
(Draft Method 1614 from EPA)

(1) Standard solutions—Prepare from materials of known purity and composition or purchase as solutions or mixtures with certification to their purity, concentration, and authenticity.

If the chemical purity is 98 % or greater, the weight may be used without correction to calculate the concentration of the standard. Observe the safety precautions in Section 5 and the recommendation in Section 5.1.2.

(1.1) For preparation of stock solutions from neat materials, dissolve an appropriate amount of assayed reference material in solvent. For example, weigh 1 to 2 mg of BDE 99 to three significant figures in a 10-mL ground-glass-stoppered volumetric flask and fill to the mark with nonane. After the compound is completely dissolved, transfer the solution to a clean 15-mL vial with fluoropolymer-lined cap.

(1.2) When not being used, store standard solutions in the dark at room temperature in screwcapped vials with fluoropolymer-lined caps. Place a mark on the vial at the level of the solution so that solvent loss by evaporation can be detected. Replace the solution if solvent loss has occurred.

See, VIP tip: Before store the standard solutions, replace a new fluropolymer-line cap, then will eliminate the introducing of caps-impurity for next analysis.

Work hard, think smart.