Mass Spectrometry

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Image Credit: © Oligo Factory
Synthesizing Synthetic Oligonucleotides: An Interview with the CEO of Oligo Factory

February 6th 2024

LCGC and Spectroscopy Editor Patrick Lavery spoke with Oligo Factory CEO Chris Boggess about the company’s recently attained compliance with Good Manufacturing Practice (GMP) International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use (ICH) Expert Working Group (Q7) guidance and its distinction from Research Use Only (RUO) and International Organization for Standardization (ISO) 13485 designations.

Potassium. Kalium. Alkali metals. Chemical Element of Mendeleev's Periodic Table. Potassium in square cube creative concept. | Image Credit: © Aleksander - stock.adobe.com
Potassium Isotopic Composition in Plants Analyzed Using MC-ICP-MS

December 12th 2023

Diatoms, algae under microscopic view, phytoplankton, fossils, silica, golden yellow algae | Image Credit: © elif - stock.adobe.com
Detecting Cadmium in Marine Phytoplankton Using Single-Cell Inductively Coupled Plasma Mass Spectrometry

December 6th 2023

Laser beam light effect | Image Credit: © donatas1205 - stock.adobe.com
New Laser Techniques Unlock Deuterium Release from Aluminum Layers

November 24th 2023

Holistic medicine approach. Healthy food eating, dietary supplements, healing herbs and flowers. Turmeric, dried lavender, spirulina powder in wooden bowls, fresh berries, omega acid capsules | Image Credit: © jchizhe - stock.adobe.com
More Than Just Acronyms at EAS 2023

November 14th 2023

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Analysis of Organic Compounds in Water Using Unique Concentration–Injection Techniques for Portable GC–MS

May 1st 2017

A simple method for extraction and concentration of trace organic compounds found in water for gas chromatography-mass spectrometry (GC-MS) analysis was developed. The method used 25 and 45 mL glass vials with a 5-10 µm thick polymer coatings for extraction of analytes from 20 and 40 mL water samples, respectively. Analytes were subsequently transferred from the polymer coating into an organic solvent, which was reduced in volume to 200-400 µL for analysis. A 10-20 µL sample from the vial was transferred to a tiny coiled stainless steel wire filament using a micro-syringe, or by dipping the coil into the sample. After air evaporation of the solvent, the coil was inserted into the heated injection port of a portable GC-MS system where the analytes were desorbed. Injection using the coiled wire filament eliminated sample discrimination of high boiling point compounds, and minimized system contamination caused by sample matrix residues. The GC-MS contained a new resistively heated column bundle that allowed elution of low-volatility compounds in less than 4 min. Analyses of organochlorine pesticides, polycyclic aromatic hydrocarbons, polychlorinated biphenyl congeners, pyrethroid insecticides, phthalate esters, and n-alkanes in water and wastewater samples were accomplished for low ppb concentrations in less than 10 min total analysis time.


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Testing the Limits of Ion Mobility Mass Spectrometry to Compare a Nonbiological Complex Drug Product and Purported Generics—A Case Study with Copaxone

May 1st 2017

Ion mobility mass spectrometry (IMMS) is a two-dimensional technique that allows separation of ionized molecules based on molecular size, shape, and mass‑to‑charge ratio (m/z). It has rapidly become a valuable application for analyzing isomeric compounds in a complex matrix (e.g., proteomic and lipidomic samples) or complex mixtures of structurally related and isobaric analytes (e.g., oil samples or polymer blends). IMMS was investigated as a possible technique to compare purported generic products with Copaxone®, a drug for treating relapsing‑remitting multiple sclerosis, which contains a very complex mixture of synthetic peptides. The analysis was performed on 15 randomly chosen batches of Copaxone® and 5 batches of purported generics that are marketed drugs in their country of origin. All samples were compared to a reference batch of Copaxone® (P53961) using Waters HDMS Compare software. The analysis produced heat maps that highlighted significant intensity differences in peptides at various m/z and drift times. A quantitative assessment of these heat maps was also performed by summing all the pixel values to produce a total pixel value (TPV). While the average TPV for the Copaxone® batches was 510811, the TPVs of the purported generics were 8-13 fold higher (2301682 to 4276572).


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Advanced Antibody–Drug Conjugate Structural Characterization by Sheathless Capillary Electrophoresis–Tandem Mass Spectrometry Using Complementary Approaches

March 1st 2017

Antibody drug conjugates (ADCs) are an emerging category of biotherapeutic products based on monoclonal antibodies (mAbs) coupled to powerful cytotoxic drugs. The production of ADCs entails the formation of species with different number of conjugates drugs. The heterogeneity of ADCs species add to the complexity originating from the mAbs microvariability. Sheathless capillary electrophoresis-mass spectrometry (sheathless CE-MS) using complementary approaches was used to perform a detail characterization of brentuximab vedotin (Adcetris, Seattle Genetics). Sheathless CE-MS instrument used as nanoESI infusion platform was involved to perform the intact and middle-up analysis in native MS conditions. The nanoESI infusion approaches enabled estimation of the average drug to antibody ratio (DAR) alongside to drug load distribution. Sheathless CZE-MS/MS method developed was used to obtain from a single injection the characterization of the amino acid sequence with complete sequence coverage. In addition glycosylation and drug-loaded peptides could be identified from MS/MS spectra revealing robust information regarding their localizations and abundances. Drug-loaded peptide fragmentation mass spectra study demonstrated drug-specific fragments reinforcing the identifications confidence. Results reveal the ability of sheathless CZE-MS/MS method to characterize ADCs primary structure in a single experiment.


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Minimizing Method-Induced Deamidation and Isomerization During Antibody Characterization to Ensure Optimal Understanding of Product Quality Attributes

March 1st 2017

Accurate evaluation of chemical modifications such as asparagine deamidation and aspartic acid isomerization is an essential component of comprehensive characterization of therapeutic monoclonal antibodies (mAbs). When located in the complementarity determining regions (CDRs), these modifications can cause a loss of function, impacting product efficacy and safety, resulting in the designation of the modification as a critical quality attribute. However, artifactual modifications can be introduced by analytical procedures, and distinguishing modifications as either critical quality attributes or method-induced artifacts is an important objective for product development. Conventional peptide mapping coupled with ultrahigh-resolution mass spectrometry offers advanced capabilities for definitive characterization of protein therapeutics. However, experimental conditions such as digestion time and pH can influence the observed level of chemical modifications, usually leading to over-estimation. In this work, a new peptide mapping method was developed specifically for mAb characterization that employs optimal enzyme pH for robustness, but short digestion times and time-course elements to minimize and monitor deamidation/isomerization, respectively, allowing a more accurate assessment of potential CDR sequence liabilities.