halides in solder flux

[kevlar49]

I have some solder wire with a flux core that is rated as REL0 per IPC-TM-650 2.3.35. I am detecting chlorine (0.3-0.8wt%) and bromine (5wt%) through EDX. Should I be able to detect that much? I thought this was < 0.5wt%. I have checked and the bromine peak at 11.9 keV is present, so clearly this isn't just a case of mistaking it for aluminum. Does the IPC test miss organic chlorides?

 

[btrueblood]

It might, if the flux or residues of it are not soluble in isopropanol/water.