diff --git a/src/conan_check_updates/conan.py b/src/conan_check_updates/conan.py
index d1f211b..051dcee 100644
--- a/src/conan_check_updates/conan.py
+++ b/src/conan_check_updates/conan.py
@@ -173,7 +173,7 @@ def version_str() -> str:
 _REQUIRES_ATTRIBUTES = ("requires", "build_requires", "tool_requires", "test_requires")
 
 
-def dequote(s: str) -> str:
+def _dequote(s: str) -> str:
     """If a string has single or double quotes around it, remove them."""
     min_length = 2
     if (len(s) >= min_length and s[0] == s[-1]) and s.startswith(("'", '"')):
@@ -196,7 +196,8 @@ def inspect_requirements_conanfile_py(conanfile: Path) -> List[ConanReference]:
             res = re.search(r"self\.(?:tool_)*requires\((.*)\)", line)
             if res:
                 args = res.group(1)
-                ref = dequote(args)
+                arg = args.partition(",")[0].strip()  # get first argument -> reference string
+                ref = _dequote(arg)
                 if len(ref) > 0:
                     refs.append(ref)
     return list(map(ConanReference.parse, refs))
diff --git a/tests/conanfile.py b/tests/conanfile.py
index 3d1fc23..58cfd97 100644
--- a/tests/conanfile.py
+++ b/tests/conanfile.py
@@ -17,6 +17,6 @@ class Example(ConanFile):
     def requirements(self):
         self.requires("openssl/3.2.0")
         self.requires('nanodbc/2.13.0')  # fmt:off
-        self.requires("ms-gsl/3.1.0")
+        self.requires("ms-gsl/3.1.0", "private")
         self.tool_requires("cmake/3.27.7")
         # self.requires("quill/3.6.0")