News from LabRulezLCMS Library - Week 7, 2025
LabRulez: News from LabRulezLCMS Library - Week 7, 2025
Our Library never stops expanding. What are the most recent contributions to LabRulezLCMS Library in the week of 10th February 2025? Check out new documents from the field of liquid phase, especially HPLC and LC/MS techniques!
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This week we bring you application and technical notes by Agilent Technologies, Waters Corporation, Knauer and Thermo Fisher Scientific and brochure by Shimadzu!
1. Agilent Technologies: PFAS Analysis in Food Packaging Using an Agilent 6495D Triple Quadrupole LC/MS
- Application note
- Full PDF for download
The increasing concern over per- and polyfluoroalkyl substances (PFAS) in food packaging materials, and their potential migration into food, requires accurate and reliable characterization methods. This study quantified 110 PFAS, including 73 native and 37 labeled compounds from food plastic bag material using an Agilent 6495D triple quadrupole liquid chromatography/mass spectrometry (LC/TQ) system. The method detection limit was within 0.2 µg/kg for all 73 target analytes. Most analytes demonstrated excellent linearity with R² values exceeding 0.99. Quality control (QC) samples, matrix spiked at 10 μg/kg, showed recovery rates ranging from 65 to 135% for 95% of the analytes, with precision (%RSD) ≤ 20%. These performance attributes highlight the sensitivity and reliability of the 6495D LC/TQ system for PFAS screening in food plastic bags.
Experimental
Instrumentation
An Agilent 1290 Infinity II LC system was used for chromatographic separation. To minimize PFAS contamination, the standard LC system fluid path was replaced with the Agilent InfinityLab PFC-free HPLC conversion kit (part number 5004-0006), which includes a bottle head assembly, pump head adapter assembly, inline filter, multiwash tubing kit, and a PFC delay column. The delay column was used to maximize the removal of the PFAS background caused by mobile phases.
For chromatographic separation, an Agilent ZORBAX RRHD Eclipse Plus C18 column (2.1 × 100 mm, 1.8 μm, part number 959758-902) was employed. A gradient method was used with an elution time of less than 15 minutes, as outlined in the Agilent PFAS MRM Database (part number G1736AA). This method involved 5 mM ammonium acetate in water (mobile phase A) and 100% methanol (mobile phase B) at a flow rate of 0.4 mL/min. The total run cycle time from injection to injection was approximately 18 minutes.
For targeted quantification, the study used the 6495D LC/TQ system equipped with an Agilent Jet Stream (AJS) ion source operating in negative ionization mode, using Agilent MassHunter LC/MS Acquisition software version 12.1 Update 3. Autotuning was performed in standard quadrupole mode to optimize instrument parameters.
Conclusion
Verification of the method, including sensitivity and recovery, confirmed a suitability for measuring PFAS at lower concentrations in food packaging materials. These robust analytical results empower food plastic bag manufacturers to make informed production decisions, ensuring compliance with future regulatory standards and enhancing consumer safety.
2. Waters Corporation: Improving the Purification Workflow With MaxPeak™ Premier OBD™ Preparative Columns: Isolation of Compounds From a Vitamin Beverage
- Application note
- Full PDF for download
Benefits
- Reduce unwanted interactions between certain compounds and the stainless steel (or other metal alloys) components in the column, promoting enhanced target compound detection, improved peak shape for precise fraction triggering, and leading to improved compound isolation and enhanced peak sensitivity for greater confidence in detecting impurities at low levels in crude sample mixtures
- Provide full scalability from UPLC™ to prep for predictable target collection using Waters’ highly-controlled OBD column packing process, ensuring that preparative columns are of similar bed density to analytical columns of the same chemistry
- Save time by eliminating column conditioning to reduce non specific adsorption prior to starting purification
Conclusion
MaxPeak Premier OBD Preparative Columns, utilizing Waters HPS™ Technology, minimize unwanted interactions between metal-sensitive compounds and metal surfaces within the column, improving peak shape and sensitivity. In purification workflows, such as isolating B vitamins from a vitamin beverage, these columns demonstrate superior performance compared to stainless-steel prep columns. The 5 µm variant reduces peak widths, while the 3.5 µm version enhances efficiency by shortening chromatographic run times and fraction collection dry-down times. Their heightened sensitivity aids in detecting and isolating low-level impurities, making them particularly valuable for high-throughput purification of compound libraries, ensuring efficient, first-time injection success while conserving both sample and process time.
3. Knauer: Determination of aromatic hydrocarbon types according to DIN EN 12916:2016
- Application note
- Full PDF for download
The content of hydrocarbons in motor diesel fuels affects exhaust emissions and fuel combustion characteristics. These emissions are measured by the cetane number, which indicates the combustion speed of diesel fuel and the compression needed for ignition [1]. Measuring these values is important to prevent incomplete burning and to protect the environment and public health. The DIN EN 12916:2016 standard is used to determine monoaromatic (MAH), diaromatic (DAH), and tri+ – aromatic (T+AH) hydrocarbons in diesel fuels containing up to 30% (v/v) fatty acid methyl esters (FAME) and petroleum distillates with a boiling range of 150 °C to 400 °C. The amount of polycyclic aromatic (Poly-AH) hydrocarbons is calculated as the sum of diaromatic and tri+ – aromatic hydrocarbons [2]. Compliance with this regulation also requires a system suitability test to ensure that the chosen HPLC hardware and selected column are appropriate for the application.
Experimental
Materials and methods
An analytical AZURA HPLC system was used for this application. It consisted of an isocratic AZURA P 6.1L pump, suitable for normal phase application, along with an AZURA RID 2.1L detector, an AZURA AS 6.1L autosampler, and an AZURA CT 2.1 column thermostat. The eluent was n-heptane at a flow rate of 1.2 mL/min, with the column temperature set to 25 °C. Detector settings were configured to 20 Hz with a time constant of 0.05 s. The column, with dimensions of 250 x 4 mm ID, was filled with Nucleodur 100-5 NH2 silica.
Conclusion
Using this instrumental setup, it is possible to determine mono and di-aromatic hydrocarbons according to the DIN EN 12916:2016.
4. Shimadzu: Open Access Software for LC/LC-MS
- Brochure
- Full PDF for download
In a typical laboratory, many analyses are repeatedly performed.
Users need to verify their PCs can be used for data acquisition and analyses, and they need to properly manage and maintain shared instruments. Accordingly, there is a need for more efficient laboratory administration. Open Solution™ software supports LC and LC-MS analysis and fractionation, under an open access environment, in which qualitative analyses and fractionation are repeatedly implemented under several analytical conditions, with instruments shared between multiple users.
Features of Open Solution
- Simple and Intuitive Sample Logging and Data Review
- A simple window configuration enables anyone to master the software in a short period of time.
- Automatic Conditioning Ensures Instruments Remain in Optimal Condition
- Instruments are always maintained in the optimal condition, even if they are shared by multiple users.
- Easy Confirmation of Analysis Data
- An email alerts users when data acquisition has finished,
and this data can be reviewed from a remote location.
- An email alerts users when data acquisition has finished,
5. Thermo Fisher Scientific: Fast analyses of anions in water with microbore columns using a compact ion chromatography system for reduced eluent use
- Application note
- Full PDF for download
This application note details the benefits of employing microbore columns in IC for the analysis of anions in water. Microbore columns, with diameters of 2 mm or less, require significantly lower eluent flow rates compared to standard bore (4 mm) columns. This presents a compelling solution to reduce eluent usage and thereby markedly decrease the volume of hazardous waste generated. Furthermore, we have achieved analysis times of under 10 minutes, increasing the analysis throughput while reducing total eluent consumption.
Experimental
Equipment
- Thermo Scientific™ Dionex™ Inuvion™ IC System equipped with integrated regenerant pump and optional column heater (P/N 22185-60104)
- Thermo Scientific™ Dionex™ AS-AP Autosampler (P/N 074921)
- Optional Thermo Scientific™ Dionex™ VP Vacuum Pump Kit for
Carbonate Removal (P/N 066463)
Software
- Thermo Scientific™ Chromeleon™ Chromatography Data System (CDS) software version 7.3.2 or later
Consumables
- Thermo Scientific™ Dionex™ IonPac™ AS22 Analytical Column
2 × 250 mm (P/N 064137) - Thermo Scientific™ Dionex™ IonPac™ AG22 Guard Column
2 × 50 mm (P/N 064135) - Thermo Scientific™ Dionex™ ACRS 500 Chemically
Regenerated Suppressor (2 mm) (P/N 085091) or Thermo
Scientific™ Dionex™ ADRS 600 Dynamically Regenerated
Suppressor (2 mm) (P/N 088667) - Optional Thermo Scientific™ Dionex™ CRD 300 Carbonate
Removal Device (2 mm) (P/N 064638)
Conclusion
This application note showcases a fast and efficient analysis of common anions while significantly reducing the volume of liquid waste generated with a microbore column and electrolytic suppression, as compared to a standard bore column and a chemically regenerated suppressor. The adoption of microbore columns plays a pivotal role in waste reduction by utilizing a lower flow rate. Both chemical and electrolytic suppression techniques yield comparable results; however, electrolytic suppression offers the added advantage of minimizing the need for manual preparation of chemical regenerants, thereby further decreasing liquid waste as well as removing the need to handle dangerous chemicals. This setup not only proves to be robust and reliable but also exemplifies a more environmentally sustainable approach to anion analysis.
6. Thermo Fisher Scientific: Enhanced calibration precision: Leveraging RSE and WLS for optimal function optimization
- Technical note
- Full PDF for download
This technical note outlines the advantages of employing relative standard error (RSE), weighted least squares (WLS) approximations, and inverse calibrations in enhancing the accuracy and precision of calibration in chromatographic analysis. It discusses the shortcomings of conventional metrics and introduces a more dependable and straightforward method for evaluating and optimizing calibration processes.
Software
Data evaluation was performed using Thermo Scientific™ Chromeleon™ Chromatography Data System (CDS) version 7.3.2. The software's RSE definition (Equation 4) includes weighting factors, expanding its use to calibration functions that must pass through the origin.5
Results and Discussion
IC
We analyzed representative anions using the Thermo Scientific™ Dionex™ IonPac™ AS23 column with a carbonate/bicarbonate eluent under isocratic conditions. Anions were detected via suppressed conductivity, with a broad calibration range of 0.01 mg/L to 40 mg/L. Initially, a linear calibration curve passing through the origin was used, yielding an RSD of 5%–12% and an r² value of approximately 0.999. However, deviations at lower fluoride concentrations indicated limitations in accuracy. Transitioning to a quadratic calibration curve improved precision, reducing RSD to 1.1% and increasing r² to 0.9999. Despite this, relative amount deviation analysis still highlighted inconsistencies at lower concentrations.
Further refinements included evaluating residual standard error (RSE) alongside RSD, revealing a significant difference in fluoride deviation (12.7% RSE vs. 1.1% RSD). Adjusting calibration methods, such as avoiding forced data through the origin and applying a weighting factor of 1/Amount², helped balance errors across the concentration range. By optimizing the calibration curve with a quadratic fit, an offset, and appropriate weighting, we achieved an improved RSE of 1.6%, with a more random scatter around the target value, ensuring higher calibration quality and reduced systematic errors.
HPLC
RSE and WLS were applied to calibrate alkylphenones using rapid separation liquid chromatography (RSLC), achieving separation of nine alkylphenones in under 12 seconds with a high data acquisition rate of 100 Hz. Butyrophenone was selected as a representative compound, with calibration spanning 1.5 orders of magnitude. Initial analysis revealed slight deviations at lower concentrations, with an RSE of 1.9%, already within EPA guidelines. Shifting from a linear calibration through the origin to one with an offset increased RSE to 3.3%, while applying a 1/Amount² weighting factor improved precision, reducing RSE to 0.98% and achieving minimal deviation across the calibration range.
Further testing of quadratic WLS for a linear function showed no significant impact on RSE or deviation plots, supporting previous recommendations that quadratic fits do not introduce errors even for linear data. While RSE and WLS refinements enhanced calibration precision, their necessity depends on whether initial setups meet RSE criteria. These adjustments are most beneficial when higher precision is required for analysis.
Conclusion
This technical note explores the advantages of using RSE, WLS approximations, and inverted calibrations to enhance calibration quality in chromatography. By optimizing calibration curves through quadratic fitting, offset adjustments, and suitable weighting factors (such as 1/Amount²), the calibration process can be significantly improved, resulting in lower RSEs and better overall calibration quality. Incorporating RSE as an evaluation tool offers a deeper understanding of calibration reliability.
