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Testosterone-2,3,4-13C3,
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T-070
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100 ug/mL in Acetonitrile
A stable-labeled internal standard for monitoring serum testosterone levels in men, women, and children by LC-MS/MS. The Centers for Disease Control (CDC) Hormone Standardization Project cites Testosterone-2,3,4-13C3 as the internal standard of choice for measurement of testosterone at low concentrations in biological fluids by LC-MS/MS. For these analyses, 13C-labeled internal standards can eliminate potential issues of isotopic exchange and minimize separation of later-eluting analytes from a higher substituted deuterium-labeled internal standard. Acetonitrile was chosen as diluent for its ease of handling and miscibility with water and biological specimens.
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(±)-Normetanephrine-D3 HCl,
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N-068
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100 ug/mL (as free base) in Methanol
Normetanephrine, a metabolite of norepinephrine, is a marker for catecholamine-secreting tumors such as pheochromocytoma. This internal standard is suitable for LC-MS/MS monitoring of normetanephrine levels in urine or plasma for diagnostic testing or endocrinology.
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