News from LabRulezLCMS Library - Week 39, 2024

Our Library never stops expanding. What are the most recent contributions to LabRulezLCMS Library in the week of 16th September 2024? Check out new documents from the field of liquid phase, especially HPLC and LC/MS techniques!

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This week we bring to you applications by Agilent Technologies, Shimadzu, Thermo Fisher Scientific, Waters Corporation, and Metrohm!

1. Shimadzu: Analysis of Pesticides Residue in Brown Rice by LCMS-8050RX - Comparison of On-Line Purification vs QuEChERS Methods

• Application

User Benefits

• Enables quick and simple sample preparation by combining the QuEChERS extraction process with an on-line purification column.
• LCMS-8050RX enables analysis with good recovery rates and reproducibility.

Introduction

With the increase in the number of regulated pesticides, more effective methods for simultaneous analysis of residual pesticides in food are required.

The QuEChERS method, which is widely used for pesticide residue analysis, is a pretreatment method that consists of an extraction step with acetonitrile and salts or a buffer and a purification step with dispersive solid-phase extraction (dSPE). The method can efficiently extract and purify pesticides without special equipment, but there are problems with operator-dependent data variability and the long time required for the process.

Revive in-line sample preparation (ILSP) columns1) (RESTEK Co.) are pretreatment columns that can be incorporated into the LC flow path for on-line cleanup of matrix-derived components. It makes the sample preparation process quicker and simpler, and it can be expected to reduce plastic consumable waste and costs associated with pretreatment.

This article describes the results of comparing the purification efficiency of a Revive ILSP column versus a dSPE using an LCMS-8050RX.

Conclusion

Simultaneous analysis of pesticides was performed using an LCMS-8050RX system. The combination of the QuEChERS method and Revive ILSP columns enabled the pretreatment process to be accelerated and simplified. On-line purification with a Revive ILSP column showed comparable recovery and reproducibility results to dSPE purification and demonstrated the ability to remove contaminants that remain with dSPE purification. Therefore, on-line purification with a Revise ILSP column could be used as a quick and simple alternative to dSPE for the QuEChERS method.

2. Agilent Technologies: Analyzing Iohexol by Compendial Method Produces Excellent Precision with Shallow Gradients Using an Agilent 1260 Infinity III LC

• Application

Abstract

Compendial methods of pharmacopoeias are the primary guidance for the analysis of pharmaceuticals. Some of these methods require conditions such as shallow gradients that are challenging for the applied liquid chromatography (LC) hardware. The Agilent 1260 Infinity III LC was designed with these requirements in mind and delivers highly precise retention times even under demanding conditions. This application note demonstrates the performance for the compendial analysis of iohexol. The method is further optimized using the same system to reduce analysis time and solvent consumption to work more efficiently and sustainably while maintaining system suitability requirements of the compendial method.

Introduction

Compendial methods found in different pharmacopoeias provide validated analytical procedures for many pharmaceuticals. These compendial methods are widely used, e.g., for quality control and impurity tests in the pharmaceutical production workflow. When introduced in a new laboratory or applied to new hardware for the first time, each method needs to be verified under "actual conditions of use".¹ To verify a method, pharmacopoeias usually describe system suitability parameters that need to be met, e.g., minimum resolution between two analytes. For a reliable determination of these parameters, LC hardware needs to deliver precise and reproducible results.

An example for a compendial method is the analysis of iohexol and its related substances.² Iohexol (Figure 1) is used as an X-ray contrast agent.³ The polar nature of the molecule causes poor retention of the main compound and its impurities on reversed-phase stationary phases. For this reason, the separation method employs a long, shallow gradient starting at highly aqueous conditions, which is demanding for any HPLC system.

This application note demonstrates the analysis of iohexol and two known impurities, applying the method described in the European Pharmacopoeia (Ph. Eur.) to a quaternary LC system. The compendial method will then be adjusted to UHPLC conditions to minimize solvent consumption and time spent per analysis. System suitability parameters, such as resolution and retention time stability, will be monitored and reported to evaluate the quality of both methods.

Conclusion

A compendial method using a shallow binary gradient was applied to separate iohexol and two impurities. Ph. Eur. system suitability parameters were passed, with retention time RSDs ≤ 0.083% (N = 8). The original 75-minute method was optimized and transferred to UHPLC conditions within the boundaries dictated by the harmonized chapter 621 of the USP4 and 2.2.46 of the Ph. Eur.⁵ The optimized method maintained the resolution achieved with the original method, improved RT RSDs to ≤ 0.044%, and reduced analysis time and solvent consumption by 66 and 71%, respectively. These numbers demonstrate that the Agilent 1260 Infinity III LC delivers highly reproducible results, even under challenging shallow gradient conditions of compendial methods, and at the same time offers the flexibility to optimize these methods to save time and operate more sustainably.

3. Waters Corporation: Repeatability and Reproducibility of the Oasis™ GCB/WAX for PFAS Analysis Cartridges in Soil/Solid Samples for EPA Method 1633

• Application

Abstract

In January 2024, EPA Method 1633 was finalized. EPA Method 1633 is the first method to incorporate the determination of 40 PFAS compounds across many challenging environmental sample matrices outside of drinking water including non-potable waters (ground water, surface water, and wastewater) as well as soil, biosolids, and tissue by LC-MS/MS analysis. EPA Method 1633 requires use of both weak anion exchange (WAX) solid phase extraction with graphitized carbon black (GCB) cleanup and is a performance-based method allowing for modifications as long as acceptance criteria for recoveries and %RSDs are met.

This application note highlights the extraction of soil samples in EPA Method 1633 using the Oasis GCB/WAX for PFAS Analysis, a dual-phase solid-phase extraction cartridge. The results meet the method's acceptance criteria and demonstrate the reproducibility of the cartridges.

Benefits

• Oasis GCB/WAX for PFAS Analysis, a dual-phase cartridge is reproducible and repeatable for EPA Method 1633 soil samples in inter-batch assays
• Reduction of manual steps, overall sample preparation time by use of the dual-phase SPE cartridge
• Acceptance criteria for recoveries and %RSDs are met for EPA Method 1633 for soil samples

Introduction

With EPA Method 1633 finalized, this introduces the first comprehensive US EPA method focused outside of drinking water for PFAS determination.¹ As the method incorporates a wide variety of matrices including ground water, surface water, wastewater, soil, biosolids, and tissue, their sample preparation to ensure reproducibility, sensitivity, and robustness is critical. In EPA Method 1633, the sample preparation incorporates two sorbents, GCB and WAX.

For soil sample analysis, the GCB is packed on top of the WAX sorbent to replicate the EPA Method 1633 where the GCB is used to clean the sample prior to WAX SPE. However, the method is performance-based and gives requirements for establishing quivalency.¹ Oasis GCB/WAX for PFAS Analysis cartridges can alternatively be used and have been tested and shown to meet the acceptance criteria for multiple non-potable water sources as described previously.² Oasis GCB/WAX is a dual-phase, or bilayer cartridge which combines both sorbents into a single device benefitting the user by removing total manual steps in the sample preparation workflow and reducing time by up to 20% compared to use of loose GCB and a WAX cartridge. Additionally, Oasis GCB/WAX for PFAS Analysis undergoes a QC-batch release test for common PFAS to ensure cleanliness during the SPE process reducing the risk of false positives.

This application note uses Oasis GCB/WAX for PFAS Analysis on soil samples showing that the acceptance criteria for EPA Method 1633 is met across three separate product lots of GCB/WAX with six replicates within each lot. This demonstrates not only robustness of the SPE product in EPA 1633 workflows, but and the repeatability and reproducibility inter-batch of GCB/WAX cartridges ensures confidence in out-of-the-box performance of the cartridges for use with complex matrices, like those in EPA Method 1633.

Conclusion

This study demonstrates the reproducibility of the dual-phase Oasis GCB/WAX for PFAS Analysis cartridges for determination of 40 PFAS and standards using the ACQUITY UPLC I-Class System and Xevo TQ-XS mass spectrometer. The cartridges are suitable for PFAS analysis in accordance with EPA 1633 guidelines for recovery and % RSD. The GCB/WAX cartridges show excellent repeatability across multiple replicates across soil samples. The data demonstrates Oasis GCB/WAX for PFAS Analysis cartridges are ideally suited for PFAS analysis from complex matrices, such as soils and solid samples like those described in EPA Method 1633. Out of the box performance is expected lot to lot and within lot for SPE when using Oasis GCB/WAX for PFAS Analysis.

4. Metrohm: Constant current constant voltage (CCCV) cycling with INTELLO

• Application

Intuitive battery analysis solutions from Metrohm Autolab

Charge/discharge cycling, or cycle testing, is perhaps one of the most fundamental techniques in battery research. This technique involves repeatedly charging and discharging a battery under controlled conditions in order to simulate real-world usage. From this, one can gather a wealth of data about the battery itself and the material inside.

Among the most important parameters are the actual (experimental) capacity, the coulombic efficiency, and the rate capability. Important insight into the underlying chemistry and potential failure mechanisms can also be obtained from analysis of the curves from cycle testing batteries.

This Application Note introduces the cycling tools which energy researchers can use in INTELLO, as well as the steps to obtain the recommended plots.

CONCLUSIONS

Within the battery cycling environment of INTELLO, batteries of different geometries and sizes can undergo cycle testing. Cycling procedures can be made quickly and conveniently in INTELLO, and the plots needed to understand the battery chemistry and behavior can be produced and analyzed with ease.

5. Thermo Fisher Scientific: Practical application of microflow LC-MS to multiresidue pesticides analysis in garlic extracts

• Application

Application benefits

• The Thermo Scientific™ Vanquish Neo™ UHPLC system delivers maximum performance 24/7 for reproducible nano-, capillary-, and microflow LC-MS applications and is designed for both novice and expert users.
• Microflow LC-MS for pesticide residues analysis in food offers greatly reduced solvent consumption compared to standard flow systems that are considered the “gold standard” in food control laboratories.
• Microflow with the Vanquish Neo UHPLC system provides enhanced sensitivity when using narrow bore columns (0.3–1.0 mm inner diameter (i.d.)) without sacrificing throughput, and at the same time, maintaining robust operation with food extracts prepared using the QuEChERS (Quick, Easy, Cheap, Effective, Rugged, Safe) sample preparation method.

Keywords: Orbitrap Exploris 120 mass spectrometer, Vanquish Neo UHPLC system, pesticides, garlic extract, microflow, QuEChERS, LC-MS

Goal

To demonstrate the benefits of using microflow LC-MS for quantitative assays—greatly reduced solvent consumption, little to no solvent waste production, and fast (~12 min) sample-to-sample cycle times.

Conclusion

• The developed microflow LC-MS method was shown to save mobile phase, thus reducing waste with significant cost savings benefit. For example, for every 100 injections, it was calculated that the method consumed only 37 mL of mobile phase A and 30 mL of mobile phase B.
• The cycle time from injection-to-injection was only 12 minutes, and therefore competitive with standard flow systems to maintain the high throughput required in high production labs.
• The observed robust area response and retention times demonstrate that the Vanquish Neo UHPLC system has a superior pumping system with low dead volume, overcoming the traditional roadblocks associated with transitioning from standard flow to microflow.
• The Orbitrap Exploris 120 mass spectrometer offers high resolution, low ppm mass accuracy, and the ability to acquire full scan data for retrospective analysis. Sensitivity gains in microflow LC-MS enable use of HRAM (high resolution accurate mass), and the method can be easily transferred to Themo Scientific triple quadrupole MS platforms.
• The Vanquish Neo UHPLC system can also be operated in a ‘trap-and-elute’ mode, and it is currently being applied to pesticide residue analysis. This is ongoing research and will be explored in further studies.