Industrial Gases Issue 02 | Page 8

THE SERVOMEX SOLUTION SERVOPRO MultiExact 4100 SERVOPRO Chroma SERVOTOUGH SpectraExact 2500 A multi-gas analyzer capable of utilizing several sensing technologies, providing a solution for O 2 assay analysis and impurity analysis for CO, CO 2 and CH 4 . It uses a Paramagnetic cell for a highly stable oxygen reading, with customized Infrared Gas Filter Correlation (GFx) technologies for the other measurements. The Chroma provides a nitrogen assay measurement utilizing Thermal Conductivity Detector (TCD) technology. When using Flame Ionization Detection (FID) with a methanizer, it also delivers impurity analysis for carbon monoxide. This is tailored for purity analysis of CO 2 and N 2 O, using Infrared sensing and specific calibration. Servomex recommends that sample temperature, pressure and flow is maintained for the most accurate analysis. MONITORING PURITY DURING MEDICAL GAS FILLING MEDICAL GASES Medical gases are defined as any gases used for the medical treatment of humans, and are regulated under the same rules as medicinal drugs. These regulations are set out in an official publication known as a Pharmacopeia, which specifies – among other things – how each gas should be produced and validated, the acceptable level of purity and official measurement methods. PROCESS MEASURING POINTS Medical gas cylinders are filled either at a facility adjacent to an Air Separation Unit (ASU) or at specific cylinder filling plants. The gas composition is measured at the source of supply, while quality is measured before and/or after the bulk gas delivery. Gases are delivered to the filling plant via pipeline from an ASU or a tanker, in a liquefied form which is stored in a cryogenic tank. For EP regulations, ASSAY OR IMPURITY MEASUREMENT TECHNOLOGY O 2 Assay Paramagnetic (MultiExact 4100) 20.4-21.4% 19.5-23.5% CO Impurity Infrared Gfx 1 (MultiExact 4100) <5ppm <10ppm CO 2 Impurity Infrared Gfx (MultiExact 4100) <500ppm <500ppm Air, synthetic medicinal O 2 Assay Paramagnetic (MultiExact 4100) 21-22.5% N/A Medical oxygen O 2 Assay Paramagnetic (MultiExact 4100) >99.5% >99.0% CO Impurity Infrared Gfx (MultiExact 4100) <5ppm <10ppm CO 2 Impurity Infrared Gfx (MultiExact 4100) <300ppm <300ppm O 2 Assay Paramagnetic (MultiExact 4100) 90-96% 90-96% CO Impurity Infrared Gfx (MultiExact 4100) <5ppm <10ppm CO 2 Impurity Infrared Gfx (MultiExact 4100) <300ppm <300ppm N 2 Assay GC TCD (Chroma) >99.5% >99.0% CO Impurity Infrared Gfx (MultiExact 4100) <5ppm <10ppm CO 2 Impurity Infrared Gfx (MultiExact 4100) <300ppm N/A N 2 Assay GC TCD (Chroma) N/A >97.0% CO Impurity Infrared Gfx (MultiExact 4100) N/A <10ppm CO 2 Impurity Infrared Gfx (MultiExact 4100) N/A <300ppm CO 2 Assay Infrared (SpectraExact 2500) >99.5% N/A CO Impurity GC FID with methanizer (Chroma) <5ppm N/A CH 4 Impurity Infrared Gfx (MultiExact 4100) <50ppm N/A Medical air Although they share some of the same rules, the United States Pharmacopeia (USP) and European Pharmacopeia (EP) have different regulations, and the acceptable concentration levels often vary. O 2 93% dedicated tankers do not need to be sampled after filling a cryogenic vessel if a certificate of analysis is provided with the delivery. The liquefied gas is vaporized into gas and pumped to the filling manifold. The quality is usually high enough that no further purification is required. There must be a dedicated manifold for each single gas, and a dedicated mixture manifold for two or more gases, with control procedures to prevent cross-contamination. Medical N 2 For multi-cylinder manifolds, the gas from at least one cylinder from each manifold filling cycle is tested for identity and assay each time the cylinders are changed on the manifold. For single gases filled one cylinder at a time, at least one cylinder per cycle is tested. N 2 97% Air is classed as a single gas so long as it is not mixed using N 2 and O 2 . ACCEPTABLE ACCEPTABLE CONCENTRATION CONCENTRATION (EP) (USP/NF 4 ) ANALYTE GAS MIXTURE Carbon dioxide Helium Argon Nitrous oxide 1 1 1 1 1 1 1 1 CO Impurity Detector Tube N/A <10ppm O 2 Impurity Paramagnetic (MultiExact 4100) Not O 23 N/A N 2 O Assay Infrared 2 (SpectraExact 2500) >98% >98.0% CO Impurity GC FID with methanizer 1 (Chroma) <5ppm <10ppm CO 2 Impurity GC TCD 1 (Chroma) <300ppm <300ppm 1 The detector tube is the measurement technology for impurities in the USP. Gas analyzers can be used as an alternative method if supported by validation tests. 2 GC TCD (Chroma) for the USP. 3 For medical argon, Servomex provides a solution that confirms it is not oxygen before it is measured using gas chromatography. 4 The National Formulary (NF) provides standards for medicinal N 2 and 93% N 2 in the US. Find the right solution for your process: servomex.com/quotes-and-enquiries P08 P09