Provided are methods for detecting chromogranin A by mass spectrometry. In another aspect, provided herein are methods for quantitating chromogranin A by mass spectrometry. In another aspect, provided herein are methods for prognosis of or measuring the size of neuroendocrine tumors by mass spectrometry.

The invention relates to the detection of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). In a particular aspect, the invention relates to methods for detecting DHA and EPA by mass spectrometry and kits for carrying out such methods.

Methods of quantifying a N.sup.2-(1-carboxyethyl)-2′-deoxyguanosine (CEdG) levels in biological samples and comparing those levels to known normal levels can diagnose a number of metabolic disorders or complications associated therewith, including diabetes, its associated complications, and cancer. Methods can also determine whether therapies for disorders are effective by measuring CEdG levels before and after treatment. Measurement of CEdG levels is achieved by using liquid chromatography electrospray ionization tandem mass spectrometry.

An electrospray emitter assembly for interfacing a separation column to a mass spectrometer is disclosed. An emitter capillary includes an inlet end and an outlet end. A fitting is coupled to the inlet end of the emitter, configured to be removably connected to the separation column. A stop with a defined through hole is integrated proximate the inlet end of the emitter to produce a path for liquid to flow from the separation column to the emitter via the through hole where a voltage is applied to the liquid entering the emitter.

An object of the present invention is to improve the safety and stability of an ion source by making a temperature distribution of a heated gas uniform while ensuring heat insulating properties. The ion source according to the present invention includes a gas introduction port inside a probe holder that holds an ion probe. A heater that increases the temperature of a heated gas and the gas introduction port are connected by a plurality of pipes which extend along an extending direction of the ion probe and are independent of each other (see FIG. 4).

An analysis method includes: performing liquid chromatography using a mobile phase including an adsorption prevention agent for preventing adsorption of a sample including a compound having a phosphate group to metal; and performing mass spectrometry on an eluate of the liquid chromatography. The adsorption prevention agent includes an oxalic acid or a salt of the oxalic acid.

The present invention relates to a method for quantifying one or more analytes in a sample by an analysis system comprising a separation unit (LC column), a means of adding a solution post-column (Connector), and a detection unit comprising a mass spectrometer coupled through an ionization source, the method comprising: ⋅ (i) inducing matrix effect on the analytes in the sample and on the post-column infused internal standards (PCI-ISs); ⋅ (ii) matching one or more post-column infused internal standard (PCI-IS) to each analyte that best matches the analyte's response to the matrix effect, and ⋅ (iii) storing the analyte-matched PCI-IS identification and, optionally, associated response data in a library; and ⋅ (iv) applying the analyte-matched PCI-IS to the analyte in other samples to correct the analyte peak responses for the matrix effect during ionization and to obtain (absolute) quantitation of the analyte using the response data.

Techniques and apparatus for ion source devices with minimized post-column volumes are described. In one embodiment, for example, an ion source assembly may include a chromatography column in fluid communication with an ion source device, the chromatography column arranged within a minimum distance of the ion source, the minimum distance comprising between about 60 mm and about 150 mm.

This disclosure provides quantitative, rapid, and reliable LC-MS/MS methods for analyzing panels of pesticides and mycotoxins in various samples, including very hydrophobic and chlorinated compounds normally analyzed on a GC-MS/MS system. The methods can be carried out using a single instrument and can detect and quantify levels of the pesticides and mycotoxins that are well below action limits specified by U.S. states (e.g., California) and other countries (e.g., Canada) for these compounds in cannabis products.

Methods are described for measuring the amount of C peptide in a sample. More specifically, mass spectrometric methods are described for detecting and quantifying C peptide in a sample utilizing on-line extraction methods coupled with tandem mass spectrometric or high resolution/high accuracy mass spectrometric techniques.