Provided are methods of detecting the presence or amount of a vitamin D metabolite in a sample using mass spectrometry. The methods generally directed to ionizing a vitamin D metabolite in a sample and detecting the amount of the ion to determine the presence or amount of the vitamin D metabolite in the sample. Also provided are methods to detect the presence or amount of two or more vitamin D metabolites in a single assay.

A method of monitoring water-soluble treatment chemicals in a fluid that is immiscible with water and which may or may not contain some aqueous fluid, the method using at least one reagent that produces an optically detectable product, the detection step can take place without separation of the aqueous phase containing the treatment chemicals from the fluid immiscible with water.

Compounds include carbamate derivatives of vitamin D including vitamin D.sub.3 and vitamin D.sub.2. The compounds are useful in methods and kits for determining the presence and/or amount of vitamin D including vitamin D analogs and metabolites thereof in a sample suspected of containing the same.

Provided are methods of detecting the presence or amount of a dihydroxyvitamin D metabolite in a sample using mass spectrometry. The methods generally comprise ionizing a dihydorxyvitamin D metabolite in a sample and detecting the amount of the ion to determine the presence or amount of the vitamin D metabolite in the sample. In certain preferred embodiments the methods include immunopurifying the dihydroxyvitamin D metabolites prior to mass spectrometry. Also provided are methods to detect the presence or amount of two or more dihydroxyvitamin D metabolites in a single assay.

An improved analytical method for analysis of dianhydrogalactitol preparations provides a method for determining the purity of dianhydrogalactitol and detecting impurities in preparations of dianhydrogalactitol, as well as identifying any such impurities. The method employs high performance liquid chromatography (HPLC), in particular, HPLC with refractive index (RI) detection; the HPLC can be followed by tandem mass spectroscopy. The method can further comprise the step of performing preparative HPLC collection of at least one specific substance peak present in a preparation of dianhydrogalactitol.

The present invention relates in particular to methods of detecting predisposition to or diagnosis and/or prognosis of Charcot-Marie-Tooth disease (CMT) and related disorders. More specifically, the invention relates to development, validation and application of new biomarkers which can be used for detecting the presence or risk of CMT disease and related disorders. In particular, the present invention relates to metabolite, lipid, carbohydrate and proteinaceous biomarkers that can be measured in biological body fluids and easily available extracts of biopsies, which can be used to aid in the detection, prediction of drug treatment and follow-up of this treatment of neurodegenerative disorders, including CMT disease. The present invention also relates to methods for identification of CMT disease subtypes and assessing the responsiveness to treatments and the efficacy of treatments in subjects having CMT or a related disorder.

Provided are methods of detecting the presence or amount of a vitamin D metabolite in a sample using mass spectrometry. The methods generally directed to ionizing a vitamin D metabolite in a sample and detecting the amount of the ion to determine the presence or amount of the vitamin D metabolite in the sample. Also provided are methods to detect the presence or amount of two or more vitamin D metabolites in a single assay.

Provided are methods of detecting the presence or amount of a dihydroxyvitamin D metabolite in a sample using mass spectrometry. The methods generally comprise ionizing a dihydroxyvitamin D metabolite in a sample and detecting the amount of the ion to determine the presence or amount of the vitamin D metabolite in the sample. In certain preferred embodiments the methods include immunopurifying the dihydroxyvitamin D metabolites prior to mass spectrometry. Also provided are methods to detect the presence or amount of two or more dihydroxyvitamin D metabolites in a single assay.

The present invention relates in particular to methods of detecting predisposition to or diagnosis and/or prognosis of Charcot-Marie-Tooth disease (CMT) and related disorders. More specifically, the invention relates to development, validation and application of new biomarkers which can be used for detecting the presence or risk of CMT disease and related disorders. In particular, the present invention relates to metabolite, lipid, carbohydrate and proteinaceous biomarkers that can be measured in biological body fluids and easily available extracts of biopsies, which can be used to aid in the detection, prediction of drug treatment and follow-up of this treatment of neurodegenerative disorders, including CMT disease. The present invention also relates to methods for identification of CMT disease subtypes and assessing the responsiveness to treatments and the efficacy of treatments in subjects having CMT or a related disorder.

Methods for determining the amount of vitamin D compounds in a sample are provided. The methods can employ LC-MS/MS techniques and optionally the use of deuterated internal standards. Methods for diagnosing vitamin D deficiencies are also provided.