diff --git a/src/main/java/de/ids_mannheim/korap/query/serialize/MetaQueryBuilder.java b/src/main/java/de/ids_mannheim/korap/query/serialize/MetaQueryBuilder.java
index 534253b..22963a5 100644
--- a/src/main/java/de/ids_mannheim/korap/query/serialize/MetaQueryBuilder.java
+++ b/src/main/java/de/ids_mannheim/korap/query/serialize/MetaQueryBuilder.java
@@ -44,26 +44,30 @@
     /**
      * context if of type paragraph or sentence where left and right
      * size delimiters are irrelevant; or 2-token, 2-char p/paragraph,
-     * s/sentence or token, char
+     * s/sentence or token, char.
+     * Distinguish
      *
      * @param context
      * @return
      */
     public MetaQueryBuilder setSpanContext(String context) {
-        if (context.startsWith("s") | context.startsWith("p"))
-            this.spanContext = new SpanContext(context);
-        else {
-            String[] ct = context.replaceAll("\\s+", "").split(",");
-            String[] lc = ct[0].split("-");
-            String[] rc = ct[1].split("-");
-            this.spanContext = new SpanContext(Integer.valueOf(lc[0]), lc[1],
-                    Integer.valueOf(rc[0]), rc[1]);
+        if (context != null) {
+            if (!context.contains("-") || context.contains(":"))
+                this.spanContext = new SpanContext(context);
+            else {
+                String[] ct = context.replaceAll("\\s+", "").split(",");
+                String[] lc = ct[0].split("-");
+                String[] rc = ct[1].split("-");
+                this.spanContext = new SpanContext(Integer.valueOf(lc[0]),
+                        lc[1], Integer.valueOf(rc[0]), rc[1]);
+            }
         }
         return this;
     }
 
     public MetaQueryBuilder addEntry(String name, Object value) {
-        meta.put(name, value);
+        if (value != null)
+            meta.put(name, value);
         return this;
     }
 
@@ -73,6 +77,8 @@
         return meta;
     }
 
+
+
     @Data
     public class SpanContext {
         private String left_type;
diff --git a/src/main/java/de/ids_mannheim/korap/query/serialize/QuerySerializer.java b/src/main/java/de/ids_mannheim/korap/query/serialize/QuerySerializer.java
index ff11926..92ac1f3 100644
--- a/src/main/java/de/ids_mannheim/korap/query/serialize/QuerySerializer.java
+++ b/src/main/java/de/ids_mannheim/korap/query/serialize/QuerySerializer.java
@@ -231,7 +231,7 @@
         return this;
     }
 
-    public QuerySerializer addMeta(MetaQueryBuilder meta) {
+    public QuerySerializer setMeta(MetaQueryBuilder meta) {
         this.meta = meta.raw();
         return this;
     }