diff --git a/src/hooks/useModerationQueue.ts b/src/hooks/useModerationQueue.ts
index 8f428485..3ece6821 100644
--- a/src/hooks/useModerationQueue.ts
+++ b/src/hooks/useModerationQueue.ts
@@ -324,20 +324,19 @@ export const useModerationQueue = (config?: UseModerationQueueConfig) => {
         .single();
 
       const expiresAt = new Date(Date.now() + 15 * 60 * 1000);
-      const now = new Date().toISOString();
       
-      const { error } = await supabase
-        .from('content_submissions')
-        .update({
-          assigned_to: user.id,
-          assigned_at: new Date().toISOString(),
-          locked_until: expiresAt.toISOString(),
-        })
-        .eq('id', submissionId)
-        .or(`assigned_to.is.null,locked_until.lt."${now}"`); // Only if unclaimed or lock expired
+      const { data, error } = await supabase.rpc('claim_specific_submission', {
+        p_submission_id: submissionId,
+        p_moderator_id: user.id,
+        p_lock_duration: '15 minutes',
+      });
 
       if (error) throw error;
 
+      if (!data) {
+        throw new Error('Submission is already claimed or no longer available');
+      }
+
       setCurrentLock({
         submissionId,
         expiresAt,
diff --git a/src/integrations/supabase/types.ts b/src/integrations/supabase/types.ts
index dedb8a94..d8079158 100644
--- a/src/integrations/supabase/types.ts
+++ b/src/integrations/supabase/types.ts
@@ -5403,6 +5403,14 @@ export type Database = {
           waiting_time: unknown
         }[]
       }
+      claim_specific_submission: {
+        Args: {
+          p_lock_duration?: unknown
+          p_moderator_id: string
+          p_submission_id: string
+        }
+        Returns: boolean
+      }
       cleanup_expired_sessions: { Args: never; Returns: undefined }
       cleanup_old_page_views: { Args: never; Returns: undefined }
       cleanup_old_request_metadata: { Args: never; Returns: undefined }
diff --git a/supabase/migrations/20251104003206_81d138c5-f4f4-4e97-a8b8-4876d91e0ce1.sql b/supabase/migrations/20251104003206_81d138c5-f4f4-4e97-a8b8-4876d91e0ce1.sql
new file mode 100644
index 00000000..310c2af9
--- /dev/null
+++ b/supabase/migrations/20251104003206_81d138c5-f4f4-4e97-a8b8-4876d91e0ce1.sql
@@ -0,0 +1,51 @@
+-- Create function to atomically claim a specific submission
+CREATE OR REPLACE FUNCTION public.claim_specific_submission(
+  p_submission_id UUID,
+  p_moderator_id UUID,
+  p_lock_duration INTERVAL DEFAULT '15 minutes'
+) RETURNS BOOLEAN
+LANGUAGE plpgsql
+SECURITY DEFINER
+SET search_path = public
+AS $$
+DECLARE
+  rows_updated INTEGER;
+BEGIN
+  -- Atomically update the submission if it's unclaimed or lock expired
+  UPDATE content_submissions
+  SET 
+    assigned_to = p_moderator_id,
+    assigned_at = NOW(),
+    locked_until = NOW() + p_lock_duration,
+    first_reviewed_at = COALESCE(first_reviewed_at, NOW())
+  WHERE id = p_submission_id
+    AND (
+      assigned_to IS NULL 
+      OR locked_until < NOW()
+    )
+    AND status = 'pending';
+  
+  GET DIAGNOSTICS rows_updated = ROW_COUNT;
+  
+  -- Log the action if successful
+  IF rows_updated > 0 THEN
+    BEGIN
+      PERFORM log_admin_action(
+        p_moderator_id,
+        (SELECT user_id FROM content_submissions WHERE id = p_submission_id),
+        'submission_claimed',
+        jsonb_build_object(
+          'submission_id', p_submission_id,
+          'claim_type', 'specific'
+        )
+      );
+    EXCEPTION WHEN OTHERS THEN
+      RAISE WARNING 'Failed to log submission claim audit: %', SQLERRM;
+    END;
+    
+    RETURN TRUE;
+  END IF;
+  
+  RETURN FALSE;
+END;
+$$;
\ No newline at end of file