Hydrogen Elemental Analysis and Testing
Established in 1956, Midwest Microlab Inc. is equipped to provide rapid accurate organic microchemical analysis to research and industry. Specialties include analysis for Carbon, Hydrogen, Nitrogen, direct Oxygen, and halogens including Fluorine.
What is Hydrogen?
Hydrogen (Latin: ‘hydrogenium’, from Ancient Greek: hydro: “water” and genes: “forming”) is a chemical element in the periodic table that has the symbol H and atomic number 1. At standard temperature and pressure it is a colorless, odorless, nonmetallic, univalent, tasteless, highly flammable diatomic gas (H2).
With an atomic mass of 1.00794 g/mol, hydrogen is the lightest element. It is also the most abundant, constituting roughly 75% of the universe’s elemental matter. Stars in their main sequence are overwhelmingly composed of hydrogen in its plasma state.
Elemental hydrogen is relatively rare on Earth, and is industrially produced from hydrocarbons, after which most free hydrogen is used “captively” (meaning locally at the production site), with the largest markets about equally divided between fossil fuel upgrading (e.g. hydrocracking) and in ammonia production (mostly for the fertilizer market).
The most common naturally occurring isotope of hydrogen contains one electron and an atomic nucleus of one proton. In ionic compounds it can take on either a positive charge (becoming a cation, a bare proton) or a negative charge (becoming an anion known as a hydride).
Hydrogen can form compounds with most elements and is present in water and all organic compounds. It plays a particularly important role in acid-base chemistry, in which many reactions involve the exchange of protons between soluble molecules.
As the only element for which the Schrödinger equation can be solved analytically, study of the energetics and bonding of the hydrogen atom has played a key role in the development of quantum mechanics.
Hydrogen Analysis & Techniques Used:
The method in use is an upgraded form of that originally researched in Switzerland and marketed by various firms in the US. Fundamentally, the scheme involves combustion of a sample in ultra-pure oxygen at 990 deg C in a closed system.
The products (gasses) are swept through copper to remove excess Oxygen and silver salts to remove halogens, phosphorus, and sulfur. Since the heat conductivity depends upon it’s composition, the mixture of remaining gasses is sensed. The H2O is removed. Later the CO2 is removed and finally only N2 remains. Sensing is done after each removal.
The instrument is calibrated using various standards from the NIST. Thus all three elements can be determined in one run from the same sample selection. Running one sample at a time enables us to check for inorganic residue post combustion.
Interferences are very few. Very high fluorine levels (>60%) can cause high nitrogen results. This can be circumvented. The optimal sample size depends upon theory. It is always best that the analyst knows all elements present (the molecular formula). If completely unknown, the operator will select about 2 mg for analysis.
This equipment does well in the analysis of air-sensitive samples. These samples are sealed under nitrogen (in a controlled atmosphere) in preweighed capsules. After removal from the glove box, the capsule is reweighed and quickly inserted into the analyzer. This “special handling” process can be done in less than four minutes thus minimizing any degradation of the sample. There is a correction made for the increased nitrogen blank from the glove box gas.
Relative sites for Hydrogen:
The reaction of alkenes with hydrogen (hydrogenation), including the manufacture of margarine.