Industrial gases company Afrox now offers six nine (N6) of HiQ, which is the global brand for a specific range of made-for-purpose gases, gas mixtures and associated products that comply with high purity and quality standards.
Afrox HiQ speciality gases include pure ‘scientific’ gases; made-to-order scientific carrier gases and mixtures; calibration mixtures for certifying the accuracy of instruments; as well as a host of special-purpose mixtures for safety, research and development in the petrochemicals, energy and mining industries, scientific laboratories and at health facilities.
“Precision matters in everything we do,” says Afrox special products and chemicals technical services manager Hans Strydom.
At the starting point of the HiQ product range are Afrox’s high purity atmospheric gases: argon, carbon dioxide, helium, nitrogen and oxygen. For use in HiQ gas formulations, each of the source gases must be of high purity. “We talk about gas purity levels in terms of a number of nines: a five nines (N5) purity, for example, is 99.999% pure, which means it has an impurity level of less than 0.001% or 10 ppm,” explains Strydom.
For modern HiQ gases, such as those that offer N6 purity levels, they contain less than 1.0 ppm of contamination. This is the basis for the HiQ 60 range, according to Strydom. These gas mixtures are designed to have a shelf life of up to 60 months, as opposed to the previous generation mixtures that could only be guaranteed for 36 months.
“When it comes to the calibration of safety-critical measuring equipment, the purity level of the calibration mix represents true value. Emissions analysis of smoke stacks at refineries, power stations and processing plants is a legal requirement and, in some cases, the emission monitors used are required to detect contaminant levels below 100 ppb,” he notes.
To calibrate these instruments, the calibration gas used must accurately mimic the polluting gas that the instrument needs to monitor – getting the measurement wrong can be costly, with potential fines. Low ppm HiQ calibration gas mixes, many of which are manufactured at Afrox’s high-quality Gas Operations Centre facility in Germiston, offer local customers legislative compliance, consistency, accuracy and cost savings, says Strydom.
Citing Afrox HiQ methane and carbon monoxide mixes, he says these are used to calibrate the monitors for ship engine rooms, and for the explosive and toxic meters used in underground gold mines. These gases pose fire and explosion dangers, so reliably monitoring their presence is essential for the safety of people working in engine rooms or underground.
In addition to the calibration gases for environmental and safety monitors, Afrox HiQ gases are widely used as carrier gases for gas chromatography-mass spectrometry (GC-MS) instruments, which are used in laboratories and testing facilities all over the world to determine the exact constituents and contamination levels of substances.
Applications include drug detection, environmental analysis, fire and explosion investigations, and the identification of unknown substance samples. GC-MS is widely used for forensic identification of substances found at crime scenes because specific samples can be traced to the criminal with 100% certainty. “Blood samples are often tested if someone has been poisoned, for example, to identify the exact poison and its source,” notes Strydom.
For GC-MS instruments, Afrox offers HiQ helium. The purity of the carrier gas is obviously very important to the accuracy of the result, but the instruments themselves are also very sensitive to oxygen, moisture and any hydrocarbon contaminants.
In the petrochemicals industry, for example, samples of a fraction from the distillation of crude oil, such as diesel, petrol or natural gas, are analysed. The chosen fraction gets vapourised and separated on a chromatography column. It then goes into the mass spectrometer, which produces a chromatogram from which every constituent element of the sample, including all the impurities, can be identified and quantified.
The result is automatically compared with a library of substances in a database, so all the constituents and their percentages are immediately identified. And, if the instrument is calibrated for a particular substance mix – Afrox is currently working on a very toxic benzene/toluene/xylene calibration gas – then tiny quantities of the contaminant of interest can be found.
For the petrochemicals industry, Strydom mentions that Afrox develops a vast range of calibration gases, which mimic the potentially harmful pollutants that need to be kept out of the fuels that are used by the industry.
HiQ gases are also widely used by water utilities which use GC-MS to pick up any dangerous pollutants such as volatile organics and other carcinogens in their water. Samples are taken of the river water coming in, the water being processed as well as the treated drinking water being delivered to consumers to ensure safety levels are being met.
“We thrive in situations where researchers are looking for local solutions that are tailor-made for African conditions, for dealing with mosquitoes and malaria, for example, as well as for a host of biochemical and health applications, such as IVF treatment,” concludes Strydom.