Set Userform Checkbox value to True if CheckBox.Caption string is found in another String

[TFiske]

Hi all, TFiske...again,

First of all, I want to thank to AlphaFrog, mehmetcik, Arkadi, bakerman2, xladept, and Winon for their help in getting me this far with this project.

Here's the new problem:

I have a Multi-Tab UserForm in which the user will check boxes if a given chemical is of a given type. Then the .Caption parameter for each box checked is concatenated with the following code and stored in a cell in column 4 of the "Chemical's" table:

    Dim chkChem As Control
    Dim ChemType As String
    Dim delim As String
    
        delim = ", "
        For Each chkChem In Me.Frm_ChemType.Controls
            If TypeOf chkChem Is MSForms.CheckBox Then
                If (chkChem.Value = True) Then
                    ChemType = ChemType & delim & chkChem.Caption
                End If
            End If
        Next

Now, on the Edit Chemical Record tab of the userform, I need to set these checkboxes to True if their caption is found in the string generated by the code above when the user selects a stored Chemical Record from a ComboBox. I've tried a few approaches but haven't gotten anywhere.
Most recently I've tried a public function with InStr:

Private Sub ctrl1_Change()

    Dim wb As Workbook
    Dim ws As Worksheet
    
        Set wb = ThisWorkbook
        Set ws = wb.Worksheets("Chemicals")

    Dim rowIndex As Long
    Dim c As Long

    rowIndex = Application.Match(Me.ctrl1.Value, ws.Columns(1), 0)
    For c = 1 To 6
        Public Function ChemCheck(ChemBaseStr As String, ChemTypeStr As String) As Boolean
            ChemBaseStr = ws.Cells(rowIndex, 4)
            ChemTypeStr = Me.Controls("chk" & c).Caption
            ChemCheck = InStr(ChemBaseStr, ChemTypeStr)
            If ChemCheck = True Then
                Me.Controls("chk" & c).Value = True
            End If
        End Function
    Next

This latest method gives me an "Expected End Sub" error. The other method's I've tried don't seem to do anything. I've attached a copy of the project. The UserForm in question is UsrFrm_ChemicalMaintenance. Thanks again!