How to concatenate id's from one model into another model.

Hi Bill,
I used your code provided above to concatenate the Ids. It worked to concatenate all the account ids but now trying to generate a list of accounts from the ids. 

It displays the if there is only one id but when trying to create a list from the concatenated list of ids it is throwing an error:

1. An error occurred while attempting to perform the following SOQL query: SELECT RecordTypeId,Name,Id FROM Account WHERE (Id in (‘001V000000av0p8IAA,001V000000aSsaBIA’)) Error:invalid ID field: 001V000000av0p8IAA,001V000000aSsaBIA