Profiling of free fatty acids in wort using an isolator column-assisted LC-MS/MS approach

Ion-Pairing Hydrophilic Interaction Chromatography for Impurity Profiling of Therapeutic Phosphorothioated Oligonucleotides

<p><strong>Our Library never stops expanding. What are the most recent contributions to LabRulezLCMS Library in the week of 22nd September 2025? Check out new documents from the field of liquid phase, especially HPLC and LC/MS techniques!</strong></p><blockquote><p><span style="font-size:20px;">👉 </span><a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/library"><span style="font-size:20px;"><strong>SEARCH THE LARGEST REPOSITORY OF DOCUMENTS ABOUT LCMS AND RELATED TECHNIQUES</strong></span></a></p></blockquote><blockquote><p><strong>👉 Need info about different analytical techniques?</strong> Peek into <a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/library"><strong>LabRulezGCMS</strong></a> or <a target="_blank" rel="noopener noreferrer" href="https://icpms.labrulez.com/library"><strong>LabRulezICPMS</strong></a> libraries.</p></blockquote><p>This week we bring you application notes by <strong>Agilent Technologies, Shimadzu </strong>and <strong>Waters Corporation </strong>and<strong> </strong>poster by <strong>Thermo Fisher Scientific / HPLC Symposium!</strong></p><h3><strong>1. Agilent Technologies: Quantitation of N-Nitroso Nebivolol in Nebivolol Tablet Formulation</strong></h3><p><strong>Using an </strong><a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/library?mainauthorItems=10&amp;search=6495D+triple+quadrupole"><strong>Agilent 6495D triple quadrupole LC/MS system</strong></a></p><ul><li>Application note</li><li><a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/labrulez-bucket-strapi-h3hsga3/an_nebivolol_tablet_formulation_6495_qqq_lc_ms_system_5994_8053en_agilent_e7f21eb12f.pdf"><strong>Full PDF for download</strong></a></li></ul><p>N-Nitroso Nebivolol is a NDSRI of Nebivolol, a beta-1 adrenergic receptor antagonist commonly used in the treatment of hypertension and heart failure. In the carcinogenic potency categorization published by the FDA, N-Nitroso Nebivolol has been categorized as Class 4, indicating the maximum allowable intake limit for the impurity to be 1,500 ng/day. Nebivolol has maximum daily dosage limit of 40&nbsp;mg for adults.</p><p>Considering a maximum daily dose of 40&nbsp;mg and allowable intake of 1,500&nbsp;ng/day for the nitrosamine impurity in the formulation under study, the specification limit of N-Nitroso Nebivolol has been calculated as 22.5 ng/mL for the 0.6 mg/mL test concentration used during this study.&nbsp;</p><p>This application note demonstrates a highly specific, sensitive, and reproducible method for the quantitation of N-Nitroso Nebivolol in a 20 mg Nebivolol tablet formulation. The method uses a 1290 Infinity II LC coupled to a 6495D triple quadrupole LC/MS/MS. The multiple reaction monitoring (MRM) conditions and ion source parameters were automatically optimized using the optimizer tool available with MassHunter Acquisition software to maximize the sensitivity of the target analyte. The API peaks were diverted to waste with the help of an integrated, software-controlled diverter valve during quantitation of the&nbsp;impurity.</p><h4><strong>Experimental</strong></h4><h5><strong>Equipment&nbsp;</strong></h5><p>The analysis was performed on a <a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/library?mainauthorItems=10&amp;search=1290+Infinity+II+LC"><strong>1290 Infinity II LC system</strong></a> coupled to a <a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/library?mainauthorItems=10&amp;search=6495D+triple+quadrupole"><strong>6495D triple quadrupole LC/MS/ MS</strong></a>. The LC system was equipped with the following&nbsp;modules: – Agilent 1290 Infinity II high-speed pump (G7120A) – Agilent 1290 Infinity II multisampler (G7167B) – Agilent 1290 Infinity II multicolumn thermostat (G7116B) – Agilent 1290 Infinity II diode array detector (G7117A)</p><h4><strong>Conclusion&nbsp;</strong></h4><p>A highly sensitive and robust MRM method was developed for the quantitation of N-Nitroso Nebivolol in 20&nbsp;mg Nebivolol tablet formulation using an Agilent 6495D triple quadrupole LC/MS system. The chromatographic method developed provided good separation between the analyte and the API. The method showed LOD and LOQ of 2 and 5 pg/mL, respectively. The minimum signal-to-noise ratio at the LOQ level was found to be more than 50:1 (Peak to Peak). The calibration curve from 5 pg/mL to 50&nbsp;ng/mL was found to be linear, with 1/x weighting. R and R2 values were 0.999 and 0.997, respectively. Spike recovery analysis showed the efficiency of sample extraction with a recovery percentage of 116.8% in API, 108.3% in placebo, and 111.8% in tablet formulation at the spiking level of 200 pg/mL. The method was found to be highly reproducible at the LOQ level, while the %RSD value for the area response of seven replicate injections was approximately 3.1%.</p><h3><strong>2. Shimadzu: Efficient Method Development for Synthetic Peptide and Related Impurities</strong></h3><ul><li>Application note</li><li><a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/labrulez-bucket-strapi-h3hsga3/an_01_00780_en_4d0aa014ea.pdf"><strong>Full PDF for download</strong></a></li></ul><h5><strong>User Benefits</strong></h5><ul><li>LabSolutions MD improves the efficiency of the entire workflow for method development of synthetic peptide and impurities.&nbsp;</li><li>Screening for multiple mobile phases and columns can be automated using mobile phase and column switching valves.&nbsp;</li><li>Molecular weights of peptides and related impurities can be estimated and accurately tracked with LCMS-2050, a single quadrupole mass spectrometer.</li></ul><p>Peptide therapeutics, characterized by specific amino acid sequences crucial to their function, can be synthesized chemically, similar to small molecule drugs. The production of synthetic peptides involves multiple steps, including deprotection, activation, coupling, and the cleavage of the final sequence from the solid support. Impurities, such as those resulting from premature chain termination or missing amino acids, can affect the safety and efficacy of the final product. Therefore, these impurities must be separated by liquid chromatography (LC). In LC analysis, selecting the appropriate mobile phase and column across a wide range of combinations is critical for achieving optimal separation, as it significantly impacts the separation. However, since the separation pattern varies depending on the peptide chain lengths, amino acid compositions, and presence of modifications, optimizing separation for each peptide sequence is time-intensive. This study describes how to efficiently find the best separation conditions for peptides and related impurities utilizing LabSolutions MD, a dedicated software for supporting method development, through both screening and optimization phases.</p><h4><strong>Experimental</strong></h4><ul><li><strong>LC System: </strong><a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/library?mainauthorItems=1&amp;search=Nexera+X3"><strong>Nexera X3</strong></a> (Method Scouting System)</li><li><strong>MS System: </strong><a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/library?mainauthorItems=1&amp;search=LCMS-2050"><strong>LCMS-2050</strong></a></li></ul><h4><strong>Automated Peak Tracking by LCMS-2050&nbsp;</strong></h4><p>LC chromatograms obtained with a gradient time of 5 min, flow rate of 0.6 mL/min, and initial concentration of 5 % and 15 %, along with molecular weights for FLP and impurities, are shown in Fig. 18. The UV spectra for each impurity are displayed in Fig. 19. The similarity between UV spectra of Met(O2), p.A1del, p.A1_E2del, p.A1_K3del, and p.A1_D5del is greater than 0.99, suggesting that peak tracking based on UV spectra would be challenging. In contrast, LabSolutions MD enables peak tracking based on molecular weights acquired by LCMS-2050, facilitating accurate identification of compounds with similar UV spectra (Fig. 18). The estimated molecular weights for each compound show small mass errors compared to the theoretical values (Table 3), which can be used to confirm the molecular weights of known compounds as well as to approximate the molecular weights of unknown impurities.</p><h4><strong>Conclusion</strong></h4><p>The separation patterns of synthetic peptides vary depending on mobile phase composition, column type, and various LC parameters, such as gradient conditions, column oven temperature, and flow rate. Separation behavior can also differ based on peptide structure, including length, amino acid composition, and the presence of modifications. Therefore, it is necessary to optimize the separation for each peptide sequence individually. However, optimizing analytical conditions through numerous analyses and data processing can be time-consuming. LabSolutions MD automates the entire workflow, including generating analysis schedules, preparing mobile phases, and processing the data, thanks to functionalities such as automated peak tracking, ranking of chromatograms, and design space visualization. This article introduced a case where the optimal separation conditions for synthetic peptides were efficiently identified through screening and optimization phases. LabSolutions MD also offers fully automated gradient optimization by AI algorithm to meet user-defined criteria. For more details, please refer to the application news, “Automatic Optimization of Gradient Conditions by AI Algorithm on Synthetic Peptide and Impurities: 01-00814”.</p><h3><strong>3. Thermo Fisher Scientific / HPLC Symposium: Sensitive cationic lipids impurities analysis with quantitation by charged aerosol detection and simultaneous mass confirmation by MS</strong></h3><ul><li>Poster</li><li><a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/labrulez-bucket-strapi-h3hsga3/po_sensitive_cationic_lipids_impurities_analysis_quantitation_po_en_3dacf61554.pdf"><strong>Full PDF for download</strong></a></li></ul><p>Cationic lipid is a critical component in lipid nanoparticle formulations for delivering nucleic acids such as mRNA, siRNA, antisense oligonucleotides etc. [2] Cationic lipids are amphiphilic molecules that possess a hydrophilic region, a hydrophobic region, and a linker structure connecting the two. [1] Charged aerosol detector (CAD) and evaporative light scattering detectors (ELSD) are preferred for characterizing lipid nanoparticle components, with CAD being the better choice for impurity quantification due to its higher sensitivity [3]. In a previous study, an inverse gradient method was developed to quantify impurities in cationic lipids raw materials.[1] To demonstrate the inverse gradient method on CAD HP, the same cationic lipids -- R-DOTAP, DLin-KC2- DMA and ALC-0315 -- were measured to this experiment as in Application note 003384 [1]. New diverter valve and software features were showcased, along with method’s sensitivity and repeatability.</p><h4><strong>Materials and methods</strong></h4><p>Using the inverse gradient method from Application note 003384 [1], to demonstrate impurity analysis in cationic lipids on the <a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/products/2176"><strong>Thermo Scientific Vanquish Charged Aerosol Detector HP (CAD HP)</strong></a> integrated in the <a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/products/743"><strong>Thermo Scientific Vanquish Flex Inverse Gradient UHPLC System</strong></a>, with parallel mass confirmation by the <a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/products/413"><strong>Thermo Scientific ISQ EM Single Quadrupole Mass Spectrometer</strong></a>.&nbsp;</p><p><strong>Methods:</strong> The workflow uses a <a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/products/743"><strong>Vanquish Flex Inverse Gradient LC system</strong></a> with Vanquish CAD HP and <a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/products/1970"><strong>Thermo Scientific Hypersil GOLD C8 column</strong></a>.</p><h5><strong>Data Analysis&nbsp;</strong></h5><p><a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/products/76"><strong>Thermo Scientific Chromeleon Chromatography Data System (CDS)</strong></a> 7.2.10 was used for data acquisition and analysis.</p><h4><strong>Conclusions&nbsp;</strong></h4><p>The CAD HP integrates perfectly into the Vanquish Inverse Gradient LC system and offers high sensitivity and excellent repeatability for quantitative cationic lipid impurity analysis, while the ISQ EM MS provides straightforward mass confirmation with high repeatability, all under compliance-ready conditions.</p><h3><strong>4. Waters Corporation: Quantitative Analysis of Four Long-Chain Lysophosphatidylcholines (LPCs) in Dried Blood Spot using Liquid Chromatography Tandem Mass Spectrometry for Clinical Research</strong></h3><ul><li>Application note</li><li><a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/labrulez-bucket-strapi-h3hsga3/720008826_en_dc154872b6.pdf"><strong>Full PDF for download</strong></a></li></ul><h5><strong>Benefits</strong></h5><ul><li>Good chromatographic resolution of all forms</li><li>Short extraction time compared to traditional methods for lipid extraction</li><li>Short analysis injection-to-injection 7 minutes</li></ul><p>Historically, very long chain fatty acids have been quantified using direct transesterification and gas chromatography methods which involve time-consuming and labor-intensive sample preparation and analysis. Consequently, simpler LC-MS/MS methods have been reported for the measurement of long-chain LPCs (LPCs generic chemical structure, Figure 1) in DBS. Interferences have been reported using positive ESI, thus researchers have developed methodologies utilizing negative ESI to circumvent isobaric interferences when there is lack of chromatographic resolution. Here a UHPLC-MS/MS method is described using acetate adducts for the reliable analysis of four long-chain LPCs in DBS for clinical research.&nbsp;</p><p>A UHPLC-MS/MS method for quantifying a panel of LPCs (C20:0, C22:0, C24:0, and C26:0-LPCs) was developed. The mobile phase composition consisted of a mixture of water, acetonitrile, and isopropanol with 5 mM ammonium acetate as a modifier. The DBS sample extraction used a working solution prepared with the deuterated LPC internal standards in methanol. The method was developed with an ACQUITY UPLC I-Class PLUS System (Fixed Loop) using an ACQUITY Premier CSH C18 Column, which provided baseline resolution of endogenous isobaric interferences for the saturated forms of the targeted LPCs. The detector was a Xevo TQ-S micro Mass Spectrometer operated in negative ESI mode. This methodology resulted in a total analysis time (injection-to-injection) of 7 minutes.</p><h5><strong>LC Conditions&nbsp;</strong></h5><ul><li><strong>LC system: </strong><a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/products/199"><strong>ACQUITY UPLC I-Class PLUS FL&nbsp;</strong></a></li><li><strong>System Detection: </strong><a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/products/209"><strong>Xevo TQ-S micro Mass Spectrometer&nbsp;</strong></a></li><li><strong>Plate:</strong> Waters 96-well Sample Collection Plate, 350 µL&nbsp;</li><li><strong>Column(s): </strong><a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/products/1952"><strong>ACQUITY Premier CSH C18 Column</strong></a>, 2.1 mm x 50 mm, 1.7 µm (p/n: 186009460)</li></ul><h5><strong>MS Conditions&nbsp;</strong></h5><ul><li><strong>MS system:</strong> Xevo TQ-S micro Mass Spectrometer</li></ul><h5><strong>Data Management&nbsp;</strong></h5><ul><li><strong>MS software: </strong><a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/products/635"><strong>MassLynx™ v4.2 Software SCN 1045&nbsp;</strong></a></li><li><strong>Informatics: </strong>TargetLynx™ XS v4.2 Software SCN1045 and QUAN Review</li></ul><h4><strong>Results and Discussion&nbsp;</strong></h4><p>During method development, different types of column chemistry, mobile phase composition, and ESI polarity modes were assessed to optimize chromatographic peak shape, analytical sensitivity and manage interferences. In positive mode, ammonium formate favored the formation of m/z 184 and m/z 104 as daughter ions for all the LPCs. The m/z 184 ion lacks specificity because most phospholipids share this moiety, so the ion m/z 104 was selected as quantifier. Having evaluated conditions in positive mode for the analysis of the four saturated LPCs, it was observed that some existing interferences were not only affecting the parent masses of the analytes but their corresponding internal standard parent ion masses too. Hence, negative ionization using ammonium acetate as modifier was assessed for the detection of LPCs. Acetate adducts [M+CH3COO]- were the most abundant parent ion masses, generated under these conditions for each LPC. The acyl-chain product ions generated in negative ionization reduce the detection of interferences coming from other phosphocholine headgroups. The latter detection conditions were used for the validation of the method presented herein.</p><h4><strong>Conclusion&nbsp;</strong></h4><p>An LC-MS/MS clinical research method for measuring C20:0, C22:0, C24:0, and C26:0 LPCs with the ACQUITY UPLC I-Class PLUS FL System, and the Xevo TQ-S micro Mass Spectrometer that:</p><ul><li>Demonstrates good linearity, with no significant carryover, or matrix effects</li><li>Offers good precision with a total reproducibility and repeatability <span>≤</span>10% CV</li><li>Offers reliability in the identification of LPCs from interfering isobaric compounds Provides good selectivity and analytical sensitivity in negative mode and is relatively fast as approximately 220 samples can be analyzed in 24 hours</li></ul>

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