A molecularly imprinted polymer sensor for sensing a target molecule includes (a) a polymer film that is molecularly imprinted with the target molecule and includes a conductive polymer having resistance sensitive to binding with the target molecule and a structural polymer providing porosity to the polymer film, and (b) interdigitated electrodes, located on a surface of the polymer film, for measuring a change in the resistance to sense said binding.

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.

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.

Provided are methods of detecting the presence or amount of a vitamin D metabolite in a sample using mass spectrometry. The methods generally are 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 estrone in a sample using mass spectrometry. The methods generally involve ionizing estrone in a sample and detecting and quantifying the amount of the ion to determine the amount of estrone in the sample.

Provided are methods for determining the amount of estrone in a sample using mass spectrometry. The methods generally involve ionizing estrone in a sample and detecting and quantifying the amount of the ion to determine the amount of estrone in the sample.

Provided are methods of detecting the presence or amount of a vitamin D metabolite in a sample using mass spectrometry. The methods generally comprise 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.

The invention provides methods for rapid and quantitative extraction and detection of coenzyme Q10 in a sample readily adaptable to high throughput screening methods. The invention further provides reagents and kits for practicing the methods of the invention.

The invention relates to the detection of fatty acids. In a particular aspect, the invention relates to methods for detecting very long chain fatty acids and branched chain fatty acids by mass spectrometry.