Screening assays and methods of performing such assays are provided. In certain examples, the assays and methods may be designed to determine whether or not two or more species can associate with each other. In some examples, the assays and methods may be used to determine if a known antigen binds to an unknown monoclonal antibody.

The present invention is directed to a method and device to desorb an analyte using heat to allow desorption of the analyte molecules, where the desorbed analyte molecules are ionized with ambient temperature ionizing species. In various embodiments of the invention a current is passed through a mesh upon which the analyte molecules are present. The current heats the mesh and results in desorption of the analyte molecules which then interact with gas phase metastable neutral molecules or atoms to form analyte ions characteristic of the analyte molecules.

The invention relates to the detection of vitamin D metabolites. In a particular aspect, the invention relates to methods for detecting derivatized vitamin D metabolites by mass spectrometry.

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.

Methods and compounds are provided to improve the desorption and ionization of analyte for mass spectrometry analysis. More specifically, it is for electrospray ionization (ESI) mass spectrometry. The method uses charged affinity molecules that can bind with analyte either temporarily or permanently to improve the desorption and ionization of analyte. The charged affinity molecules can be positively charged or negatively charged.

The present invention is directed to a method and device to desorb an analyte using heat to allow desorption of the analyte molecules, where the desorbed analyte molecules are ionized with ambient temperature ionizing species. In various embodiments of the invention a current is passed through a mesh upon which the analyte molecules are present. The current heats the mesh and results in desorption of the analyte molecules which then interact with gas phase metastable neutral molecules or atoms to form analyte ions characteristic of the analyte molecules.

The present invention relates to a metabolic biomarker set for use in assessing breast cancer in a mammalian subject. In particular, the invention relates to a metabolic biomarker set for screening and/or diagnosing breast cancer, the metabolic biomarker set comprising at least (a) one amino acid selected from glutamine, glutamate and serine, and one lipid, or (b) glutamine and glutamate. Further, the invention relates to a metabolic biomarker set for prediction of therapeutic response to breast cancer neoadjuvant chemotherapy. Further, the invention relates to a metabolic biomarker set for assessing biochemical reflection of breast cancer tumor activity. Further, the invention relates to a metabolic biomarker set for subclassification between intrinsic breast cancer tumor subtypes. Moreover, the present invention relates to a method for assessing breast cancer, which comprises obtaining a biological sample, preferably blood, from a mammalian subject and measuring in the biological sample the amount and/or ratios of metabolites. By employing the specific biomarkers and the method according to the present invention it becomes possible to more properly and reliably assess breast cancer.

Methods are described for measuring the amount of one or more of vitamin A, α-tocopherol, and the combination of β-tocopherol and γ-tocopherol in a sample. More specifically, mass spectrometric methods are described for detecting and quantifying one or more of vitamin A, α-tocopherol, and the combination of β-tocopherol and γ-tocopherol in a sample.

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 for determining the amount of tamoxifen and its metabolites in a sample by mass spectrometry. In some aspects, the methods provided herein determine the amount of norendoxifen. In some aspects, the methods provided herein determine the amount of norendoxifen and tamoxifen. In some aspects, the methods provided herein determine the amount of norendoxifen and other tamoxifen metabolites. In some aspects, the methods provided herein determine the amount of tamoxifen, norendoxifen, and other tamoxifen metabolites.