The Future of HPLC/GC Solvents: Glass vs Aluminum Packaging
Traditional soda lime silica (SLS) glass bottles have long been the industry standard for the packaging of solvents; however, they may introduce unwanted ions such as Na+, K+, Ca++ and Fe+++ over time.
The latest research compares the performance of solvents packaged in specially treated SLS glass and aluminum containers to establish a novel multi-purpose grade of HPLC/GC solvents. Both types of packaging feature PTFE-lined closures and inert gas blankets to maintain purity and promote better chromatographic separation.
This poster explores groundbreaking research which uncovers the economic efficiencies and environmental benefits of aluminum packaging for select HPLC/GC solvents.
Download this poster to discover:
Valuable ICP-MS data confirming the suitability of aluminum packaging for specific solvents The superior purity and performance of high-quality solvents in both HPLC and GC systems How to save on costs if your lab depends on large volumes of solvents
Metal Ion Pick Up by Solvent (ICP-MS) • Storage in SLS glass increases sodium content in every solvent tested but water – although only methanol exceeds the desired target of 100 ppb • Aluminum leached in methanol as well, but well below the desired target specification of 30 ppb • Aluminum container is not suitable for packaging chromatographic water • In all solvents investigated except for water, aluminum provides a comparable or better metals profile than a comparably sized SLS container • The two main elements affected by packaging are Na and Al Blank HPLC Gradient from both Package Types • In spite of the aluminum pick up by water detected via ICP-MS, the water blank packaged in aluminum passed the HPLC specification • In order to avoid any potential interactions, for subsequent gradient analyses water packaged in SLS glass bottle was used The results are very comparable in both containers and passed LC-UV specifications. Peak Retention (min) Compound 1 1.177 Uracil 2 5.315 Phenol 3 8.795 Methyl Paraben 4 10.627 Ethyl Paraben 5 11.613 Propyl Paraben 6 12.342 Butyl Paraben 7 13.717 Heptyl Paraben ABSTRACT HPLC mobile phase solutions typically are packaged in Soda Lime Silica “SLS” bottles in spite of the potential to be a source of Na+, K+, Ca++ and Fe+++ ions with prolonged storage. Some of these ions are known to interfere with HPLC analyses via chelation with column matrices. Although aluminum containers have been used to package HPLC solvents, market acceptance has been slower for reasons including cost. In contrast, comparably sized SLS packages have a significant advantage including the perception that materials packaged in glass are purer. This poster presents the differences between glass and aluminum packaging for a new multi-purpose grade of HPLC/GC solvents, Thermo ScientificTM ChrompleteTM. The SLS glass used is specially-treated. Both packages feature a PTFE-lined closure system and inert gas blanket to maintain purity. GC chromatograms of residual pesticides are demonstrated for both packages together with HPLC analysis of pesticide standard mix. Additionally, ICP-MS analysis of metal content with storage is presented. Economic efficiency of aluminum vessels is discussed as a function of size. INTRODUCTION Analytical laboratories need to balance many issues to optimize their performance. Among these are total cost of ownership, the increasing demand for repeatable and reliable reagents, and concerns about the environment. Pesticide analysis, for example, is most frequently conducted using normal phase chromatography which can include chlorinated solvents. Packaging of these reagents is most often in relatively heavy, but reliable glass vessels. This poster shows a comparison of glass and aluminum packaging for a new multi-purpose grade of HPLC/GC solvents. Data are presented for HPLC and GC testing of a HPLC gradient diagnostic mix and a pesticide mixture using this new solvent grade. MATERIALS AND METHODS Acetonitrile, water, methanol and 2-propanol are commonly used in reversed phase HPLC for the separation and purification of compounds in a mixture. They are typically packaged in SLS glass because of its resistance to chemical attack. Solvents can interact with the package via leaching of metal ions which increases with storage time. The mobility of the Na ion is of concern because of its tendency to form metal adducts which can interfere with LC/MS analysis, and because it is a major component of SLS glass. The impact of packaging on solvent purity is important with respect to establishing better chromatographic separation and an interference free baseline. Application of Chromplete solvents as a function of packaging is demonstrated for the chromatographic analysis of compounds in HPLC diagnostic and pesticide mixtures. Different columns in HPLC are used to show the performance of the solvents and the effect of metal contamination. Instruments and Consumables Standards and Mobile Phase: • Thermo Scientific iCAP-Qs with the collision cell. All elements were tested in the KED mode • Supelco HPLC Gradient System Diagnostic Mix (Cat. No. 48271) was purchased from Sigma-Aldrich, St. Louis, MO • LC Multi-Residue Pesticide Standard #7 was purchased from Restek, Bellefonte, PA • HPLC system: Thermo Scientific Ultimate 3000 system and Agilent 1260 system with diode array detector • Columns used: Hypersil Gold (Thermo Scientific), Poroshell EC (Agilent) • Gradient: • 0 min 10% organic 90% aqueous • 2 min 10% organic 90% aqueous • 10 min 95% organic 5% aqueous • 20 min 95% organic 5% aqueous Pesticide Standards RESULTS Chromplete Acetonitrile with HPLC Traces for Three Lots CONCLUSIONS The ICP-MS data clearly indicates that there was no aluminum leaching in the case of 2-propanol or acetonitrile. Although methanol leached Al from the aluminum container, when methanol was packaged in SLS more Na was observed to leach compared to Al resulting in an overall improved metals profile. Aluminum packaging is not suitable for water as evident from extensive leaching of Al which makes water incompatible for long term chromatographic use, since elevated Al in mobile phase solvents can cause chelation in columns. Aluminum is an appropriate choice for labs that buy acetonitrile, 2propanol or methanol regularly by the case and want to reduce receipts (number of transactions), shipping costs and container disposal costs. Shipment and disposal costs could be one metric ton per year depending on usage. Chromplete solvents are of high purity and suitable for use in any HPLC system as well as in GC systems (data not shown). A blank gradient run for water and organic solvent clearly indicates the interference free baseline for each of the solvents. The analysis of seven compounds in HPLC diagnostic mix using these solvents showed a higher resolution and good signal to noise ratio for each of the compounds. The mixture of pesticide compounds was tested using water/methanol gradient with a good resolution observed. Pesticide residue testing for acetonitrile from aluminum cans and glass bottles showed very comparable results. • Aluminum is suitable for packaging of HPLC/GC methanol, 2-Propanol and Acetonitrile solvents such as Chromplete • Chromplete solvents are suitable for HPLC separation of compound mixtures whether they are packaged in SLS glass or aluminum • All solvents are suitable for use in GC-FID systems • For large solvent users, use of aluminum packaging can result in significant laboratory efficiencies including shipping and disposal costs, reduced receipts, and potential size based discounts REFERENCES 1.Typical as reported by “High Temperature Glass Melt Property Database for Process Modeling”, Eds.: Thomas P Seward III and Terese Vascott; The American Ceramic Society, Westerville, OH COPYRIGHT/TRADEMARKS © 2019 Thermo Fisher Scientific Inc. All rights reserved. All trademarks are the property of Thermo Fisher Scientific and its subsidiaries except as otherwise indicated. This information is not intended to encourage use of these products in any manner that might infringe the intellectual property rights of others. A. M. Conlon, S. Bhattacharya, S. Brookes-Bertolatus, D. Clain, E. Oliver, J. Pardiwala, A. Kaczmarski, S. Roemer H