XL 2013 Envoyer mail via macro suite modification tableau excel

Private Sub Worksheet_Change(ByVal Target As Range)
    If Target.Column = 1 Then       'Colonne 1 testée (A)
        [B1] = "La colonne A a été modifiée"
    End If
End Sub

Private Sub Workbook_Open()
    [B1] = Empty                                'Cellule cible remise à vide
End Sub

Private Sub Workbook_BeforeSave(ByVal SaveAsUI As Boolean, Cancel As Boolean)
    If [B1] <> Empty Then                       'Teste la cellule cible
        Dim ol As Object, monmail As Object
        DisplayAlerts = False
        Set ol = CreateObject("outlook.application")
        Set monmail = ol.CreateItem(olMailItem)
        monmail.To = "xxx@mail.com"
        monmail.Subject = "Tableau de demande d'amélioration"
        monmail.Body = "Une modification a été apporté sur le tableau de demandes d'amélioration"
        monmail.Send
        Set ol = Nothing
    End If
End Sub