Table 2|.

Troubleshooting table^a

Step	Problem	Possible Reason	Solution
11	[18F]Fluoride is retained on QMA cartridge	Connections to QMA cartridge are leaking or wrong cartridge used	Check connections, replace as needed
15	Low incorporation of 18F	Equipment malfunction, decomposition of reactants	Ensure synthesis module is clean and functional, check and replace reactants as needed
15	BPin precursor 1 ceases to be commercially available	Economic / patent considerations	Prepare Bpin precursor 1 according to the procedure provided in Box 2
16	Low purity after deprotection	Ascorbic acid is degrading	If it becomes an issue, check and replace ascorbic acid if needed.
18	Slow (or no) loading of crude reaction onto HPLC loop	HPLC loop is blocked	Clean HPLC loop
18	More radioactive impurities in HPLC trace	Not enough acid in Deprotection Solution	Increase the amount of 36.5 – 38.0% HCl in Deprotecting Solution by 0.1 mL increments, or use fresh 36.5 – 38.0% HCl.
19, 27	Low chemical and/or radiochemical purity	[18F]FDOPA was not adequately purified	Clean or replace guard column and semi-preparative HPLC column
20,21, 30	Too much MeCN in [18F]FDOPA product	MeCN used during reformulation was not adequately removed	Optimize rinsing and drying in Steps 20 and 21

^aMany of the problems in this table can be be avoided by following cGMP.