What is a Mass Spectrometer?
A mass spectrometer is an instrument that measures the masses of individual molecules that have been converted to ions, i.e., are electrically charged. Since atoms are so small, it is inconvenient to measure their masses in kilograms, grams or pounds. In fact, the mass of a single hydrogen atom is approximately 1.66×10-24 grams i.e. (0.00000000000000000000000166). We therefore need a more convenient unit for the mass of individual molecules. This unit of mass is often referred to by chemists and biochemists as the Dalton (Da for short) and is defined as follows: 1 Da = (1/12) of the mass of a single atom of the isotope carbon-12 (12C). On this scale one hydrogen atom has a mass of 1.0078, a nitrogen atom 14.0037, oxygen 15.9949 and sulphur 31.9721, for example. A mass spectrometer does not actually measure mass directly but rather the mass-to-charge ratio of ions formed. Because it is inconvenient to measure the charge on an individual ion in everyday units of measurement, we use the f
A mass spectrometer is an instrument that measures the masses of individual molecules that have been converted into ions, i.e., molecules that have been electrically charged. Since molecules are so small, it is not convenient to measure their masses is kilograms, or grams, or pounds. In fact, the mass of a single hydrogen atom is approximately 1.66 X 10-24 grams. We therefore need a more convenient unit for the mass of individual molecules. This unit of mass is often referred to by chemists and biochemists as the dalton (Da for short), and is defined as follows: 1 Da=(1/12) of the mass of a single atom of the isotope of carbon-12(12C). This follows the accepted convention of defining the 12C isotope as having exactly 12 mass units. As will become clear in what follows, a mass spectrometer does not actually measure the molecular mass directly, but rather the mass-to-charge ratio of the ions formed from the molecules. For reasons similar to those discussed in the context of mass, it is i
A mass spectrometer is a device that can be used to determine the chemical composition of a sample with high degrees of accuracy. The enabling techniques were developed early in the 20th century by a number of scientists. The mass spectrometer is put to use many thousands of times each day by researchers in labs and universities worldwide. The mass spectrometer works based on the principle that different chemicals have different masses. To determine the mass of chemicals in a sample, the sample is first vaporized, then ionized. The result is an ionized gas that is accelerated through a chamber. Because ionized gases respond to magnetic fields, a magnet on the wall of the chamber is used to bend the ions towards a detector. Lighter ions are bent quickly towards the detector, while heavier ions are bent at a slower rate. The resulting distribution of ions, called a mass spectra, can be used to determine the content of the original sample. There are many different types of ionization for
