News from LabRulezLCMS Library - Week 50, 2024

Our Library never stops expanding. What are the most recent contributions to LabRulezLCMS Library in the week of 9th December 2024? Check out new documents from the field of liquid phase, especially HPLC and LC/MS techniques!

👉 SEARCH THE LARGEST REPOSITORY OF DOCUMENTS ABOUT LCMS AND RELATED TECHNIQUES

👉 Need info about different analytical techniques? Peek into LabRulezGCMS or LabRulezICPMS libraries.

This week we bring you applications by Shimadzu, Metrohm, and  Waters Corporation, a presentation by Agilent Technologies, and a poster from MSACL by Thermo Fisher Scientific!

1. Shimadzu: Analysis of Per- and Polyfluoroalkyl Substances (PFAS) using Triple Quadrupole Mass Spectrometer Part 1 - Fish Fillet

• Application

User Benefits

• The optimized procedure for pretreatment and LC-MS/MS analytical conditions enable accurate quantification of thirty major PFASs targeted by AOAC SMPR from 0.1 μg/kg.
• The method allows the initiation of PFASs analysis in food.

Introduction

Per- and Polyfluoroalkyl Substances (PFASs) are a collective name for more than four thousand organofluorine compounds. Perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) are representative compounds of PFAS. They are used in a wide range of applications, such as fire retardants, food packaging materials, and non-stick coatings, due to their water-repellent, oil-repellent, heat-resistant, and chemical-resistant properties. Due to their structural stability, PFAS widely remains in the environment. There are concerns about health risks caused by human ingestion of fish that have ingested seawater, river water, or feed contaminated with PFAS. Therefore, quantitative assessment of PFAS levels in fish should be important.

This application news introduces a quantitative analysis of PFAS in tuna fillets with LC-MS/MS. Thirty principal PFASs targeted by AOAC INTERNATIONAL, a North American organization that standardizes food testing methods and verifies analytical methods, were analyzed using newly created method, which was investigated from the pretreatment procedure then validated by recovery test. By reducing losses during the pretreatment and optimizing the analytical conditions, good recovery rates were obtained for all compounds.

Conclusion

This application news described a quantitative analysis of thirty PFAS targeted by AOAC INTERNATIONAL in tuna fillet. The analysis was performed using a quadrupole mass spectrometer LCMS-8060NX equipped with ultra-high performance liquid chromatograph Nexera X3 UHPLC system. Shim-pack Scepter, which provides good separation and peak shape, was used as the column. A spiked recovery test were conducted, and all compounds showed recovery rate within 80-120% and repeatability below 20% at spiked concentrations of 0.1, 1, 5 μg/kg. In particular, recovery rates of PFOS, PFOA, PFNA, and PFHxS were within 95.5-108.4% at all spiked concentrations. Using optimized pretreatment and analytical methods, accurate quantitation is possible from 0.1 μg/kg.

2. Agilent Technologies: Getting the Most from Your Diode Array Detector

• Presentation

Agenda

• Introduction
• Fundamentals
  • Beer-Lambert law
  • UV-vis detection
  • DAD and MWD
  • DAD spectra collection
  • UV spectrum confirmation
  • peak purity
• Maximizing sensitivity
  • What is sensitivity?
  • Factors affecting sensitivity
  • Analyte
  • Factors affecting sensitivity
  • System
  • Detector
• Spectral acquisition
  • Settings
  • Spectrum storage
  • Range, step, and threshold
  • OpenLab Resources
• DAD maintenance
  • Maintenance schedule
  • InfinityLab LC performance standard
  • Lab advisor
  • Care of flow cells
  • Flow cells
  • Best practices
  • Maintenance resources
• Troubleshooting
• Additional Resources

3. Waters Corporation: HPLC Autosampler Performance II: Improved Injection Precision of USP Methods With the Alliance™ iS HPLC System

• Application

Abstract

Method conditions and instrument characteristics can affect the autosampler performance of High-Performance Liquid Chromatography (HPLC) systems. Challenging method conditions, such as low injection volume and highly organic sample diluents, require high precision to meet strict suitability requirements. Instrument characteristics, such as sample aspiration mechanism and injector draw rate, often vary between vendors and may impact the precision performance of the autosampler. This can pose a challenge for analytical laboratories that desire to run methods with strict precision suitability criteria across HPLC systems from different vendors. In this study, the injection precision performance of the Alliance iS HPLC System and similar HPLC systems were compared using four compendial HPLC methods from the United States Pharmacopeia (USP) with strict precision criteria and challenging method conditions. Peak area reproducibility was evaluated as a proxy for autosampler performance of each system.

Benefits

• High precision for a range of sample diluents and injection volumes on the Alliance iS HPLC System
• Meets strict injection precision criteria for challenging USP methods on the Alliance iS HPLC System
• Demonstrates improved precision on the Alliance iS HPLC System over similar HPLC systems for highly organic sample diluent

Introduction

For many regulated methods in the United States Pharmacopeia (USP), injection precision is a common system suitability criterion. Injection precision is a measure of the autosampler performance in a high-performance liquid chromatography (HPLC) system. The autosampler is responsible for delivering precise aliquots of sample to the HPLC system flow path.¹ This performance can be impacted by method conditions and instrument characteristics.^2,3,4 To ensure that acquired data is accurate and meets suitability requirements of the method, high performance is required from an autosampler.

Instrument characteristics, such as sample aspiration mechanism and injector draw rate, vary among vendors due to differences in system design. Sample aspiration is typically controlled by either a metering device or a sampling syringe.¹ Injector draw rate is a setting typically set to a default speed that often varies with instrument vendor.⁴ These different characteristics can complicate running methods across systems from different vendors. A routine method that performs well on one HPLC system may not meet system suitability criteria on a different HPLC system. Therefore, it is important to consider how autosampler performance is affected by instrument characteristics.

In this study, four USP Assay monographs were used to examine the impact of instrument characteristics on injection precision of an Alliance iS HPLC System and comparable HPLC systems. The HPLC systems include sampling syringe and metering device aspiration mechanisms and utilize different injector draw speeds. The USP Assay methods have challenging method conditions: varying organic content in the sample diluent (20%–100% organic), low injection volumes (6.6 μL–20 μL), and narrow injection precision criteria (0.73% to 2.0%).

Conclusion

The ability of an HPLC system to acquire consistent, repeatable data is critical and requires high performance from an autosampler. This study examined the impact of instrument characteristics, such as sample aspiration mechanisms and injector draw rates, on HPLC performance in meeting precision requirements. Autosampler performance is complex and was found to vary with the method and the system. The metering device has benefits for precision performance over the sampling syringe, using a more finely tuned syringe draw motor and being located in-line with the high-pressure flow path.

For fluconazole and ketoconazole USP assays, the Alliance iS HPLC demonstrated the best performance overall, with the lowest peak area %RSDs. The ketoconazole assay had particularly challenging method conditions and produced widely varying results among the HPLC systems. Alliance iS HPLC System demonstrated high precision and produced consistent and reproducible results across the three-day period, meeting the stringent 0.73% peak area RSD requirement.

The ketoconazole assay produced disparate results among the HPLC systems using metering devices, which was unexpected. Upon tracking the absolute peak area of ketoconazole for each system, evaporation and carryover were ruled out as causes of the peak variability. Additionally, despite identical injector draw rates on two of the HPLC systems, their performance varied significantly. While aspiration mechanism and injector draw rate are important factors, they do not fully explain the observed variations in autosampler performance.

4. Metrohm: Calcium acetate assay in calcium acetate capsules

• Application

Method validation according to the U.S. Pharmacopeia (USP)

Calcium acetate functions as a phosphate binder in the gastrointestinal tract, helping to lower high phosphate levels in individuals with kidney disease who are receiving dialysis treatment [1,2]. To meet the stringent quality standards for pharmaceutical products, manufacturers and laboratories must use validated methods from the United States Pharmacopeia – National Formulary (USP-NF). Previously, such methods included titration or liquid chromatography (LC) with UV detection. As part of their modernization efforts, the USP has updated the calcium monograph to include ion chromatographic (IC) analysis, which is more straightforward and sensitive than previous methods. For the calcium acetate assay, the USP specifies ion chromatography using a cation-exchange column with L76 column material and non-suppressed conductivity detection to quantify the amount of calcium ions in calcium acetate capsules [3].

The current IC method employs a Metrosep C 6 -150/4.0 column (L76) to separate calcium from other ions in calcium acetate capsules. This method has been validated according to USP General Chapters <621> Chromatography [4] and <1225> Validation of Compendial Procedures [5]. All acceptance criteria for the calcium acetate assay in the USP monograph «Calcium Acetate Capsules» are met.

SAMPLE AND SAMPLE PREPARATION

The standard solution nominally contains 0.08 mg/mL of USP Calcium Acetate Reference Standard (Cat#1086334) in water. It is prepared by accurately weighing 80.0 mg of USP Calcium Acetate Reference Standard and transferring it into a clean 1000 mL volumetric flask. It is dissolved and made up to the mark with ultrapure water (UPW).

For sample stock solutions nominally containing 6.7 mg/mL of calcium acetate, an appropriate portion of the contents of at least 20 capsules are transferred
into a 2000 mL volumetric flask. UPW is added to about 40% of the final volume of the volumetric flask, and the solution is then sonicated for 30 minutes with intermittent shaking. Afterwards, the solution is made up to the mark with UPW and filtered through 0.2 μm filter paper.

For sample solutions nominally containing 0.08 mg/mL of calcium acetate, 5.97 mL of sample stock solution are transferred into a clean 500 mL volumetric flask. This is diluted and made up to the mark with UPW. All solutions are sonicated for 5 minutes before injection.

CONCLUSION

According to the USP monograph for calcium acetate capsules [3], the assay for calcium acetate involves determining calcium content using ion chromatography (IC) on a separation column with L76 packing material (here: Metrosep C 6). The validation results met all requirements of the monograph and adhered to the guidelines specified in USP General Chapters <621> Chromatography and <1225> Validation of Compendial Procedures [4,5]. The described IC method is appropriate for quantifying calcium in calcium acetate capsules.

5. Thermo Fisher Scientific / MSACL: Quantitation of a Panel of Per- and Polyfluoroalkyl Substances (PFAS) in Human Serum

• Poster (MSACL)

Abstract

Purpose: Develop an LC-MS analytical method for quantitation of PFAS compound in human serum.

Methods: Human serum samples were spiked with 37 PFAS compounds followed by protein precipitation with 4x volume of methanol. The supernatant was analyzed on an LC-MS system equipped with low-PSAF tubing and a delay column to minimize background interferences.

Results: LOQs from 0.025 to 2.5 ng/mL were reached for all compounds.

Introduction

Per- and polyfluoroalkyl substances have been monitored in environmental and industrial samples for some time. Wellness panels are becoming more frequent and quantitating PFAS in biological samples are a part of these panels. Due to the evolving regulations and discoveries of potential health effects with these compounds it important to measure a wide range of PFAS compounds.

Conclusions

• 10-minute method for 37 PFAS compounds on the Vanquish UHPLC and TSQ Altis Plus was developed. The method showed good accuracy and precision measurements.
• While this method used simple protein precipitation for sample processing, future work includes developing an SPE method to enhance detection limits.