Product Description

This lyophilised 13C3-testosterone internal standard is developed for use in quantitative LC-MS/MS workflows where internal standardisation is applied in combination with calibration curves.

After reconstitution, the product provides a working solution that can be directly added to samples, depending on the method design. A reconstitution volume of 6 mL is typically used, but alternative volumes may be applied to match specific analytical requirements.

Within serum and plasma workflows, typical use may result in an approximate 1:2 internal standard-to-sample volume ratio (e.g. 100 µL sample + 50 µL internal standard), depending on the method setup.

For other matrices, the product can be used as part of method development. Internal standard response should be evaluated and, where required, adjusted by the user based on matrix effects, extraction procedures and instrument conditions.

Role of the Internal Standard

This product is intended for use as an internal standard in combination with calibration standards. In this context, absolute concentration of the internal standard is not critical, provided that the signal is consistently detectable and suitable for ratio-based quantification.

If used outside a calibration-based workflow (e.g. as a single-point reference), the concentration becomes method-dependent and should be defined and validated by the user.

Why 13C Instead of Deuterium (D)?

13C-labelled testosterone closely matches the chromatographic behaviour of native testosterone. This enables method optimisation based on analyte elution, without the need to compensate for isotope-related retention differences that may occur with deuterium-labelled standards.