Identification of novel microcystins in algal extracts by a liquid chromatography-high-resolution mass spectrometry data analysis pipeline.

Background: Microcystins are an emergent public health problem. These toxins are secondary metabolites of harmful cyanobacterial blooms, with blooms becoming more prevalent with eutrophication of water. Exposure to microcystins can result in sickness, liver damage, and even death.

Detection of Anatoxins in Human Urine by Liquid Chromatography Triple Quadrupole Mass Spectrometry and ELISA.

Harmful cyanobacterial blooms are becoming more common and persistent around the world. When in bloom, various cyanobacterial strains can produce anatoxins in high concentrations, which, unlike other cyanobacterial toxins, may be present in clear water. Potential human and animal exposures to anatoxins occur mainly through unintentional ingestion of contaminated algal mats and water.

Use of Diagnostic Ions for the Detection of Fentanyl Analogs in Human Matrices by LC-QTOF.

To combat the ongoing opioid epidemic, our laboratory has developed and evaluated an approach to detect fentanyl analogs in urine and plasma by screening LC-QTOF MS/MS spectra for ions that are diagnostic of the core fentanyl structure. MS/MS data from a training set of 142 fentanyl analogs were used to select the four product ions and six neutral losses that together provided the most complete coverage (97.2%) of the training set compounds.

Application of the fentanyl analog screening kit toward the identification of emerging synthetic opioids in human plasma and urine by LC-QTOF.

Human exposures to fentanyl analogs, which significantly contribute to the ongoing U.S. opioid overdose epidemic, can be confirmed through the analysis of clinical samples.

Quantitation of saxitoxin in human urine using immunocapture extraction and LC-MS.

Aim: An immunomagnetic capture protocol for use with LC-MS was developed for the quantitation of saxitoxin (STX) in human urine.

Materials & Methods: This method uses monoclonal antibodies coupled to magnetic beads. STX was certified reference material grade from National Research Council, Canada.

Association between exposure to o-chlorobenzylidene malononitrile (CS riot control agent) and urinary metabolite 2-chlorohippuric acid in U.S. Army Mask Confidence Training.

This study was conducted among U.S. Army soldiers to evaluate the association between exposure to o-chlorobenzylidene malononitrile (CS riot control agent) and urinary metabolite 2-chlorohippuric acid (CHA) detected in test subjects (n = 87) after completion of Mask Confidence Training.

Development and validation of a high-throughput online solid-phase extraction-liquid chromatography-tandem mass spectrometry method for the detection of gonyautoxins 1&4 and gonyautoxins 2&3 in human urine.

Paralytic shellfish toxins (PSTs), including gonyautoxins and saxitoxins, are produced by multiple species of microalgae and dinoflagellates, and are bioaccumulated by shellfish and other animals. Human exposure to PSTs typically occurs through ingestion of recreationally harvested contaminated shellfish and results in nonspecific symptomology. Confirmation of exposure to PSTs has often relied on the measurement of saxitoxin, the most toxic congener; however, gonyautoxins (GTXs), the sulfated carbamate derivatives of saxitoxin, may be present in shellfish at higher concentrations.

Development and validation of a high-throughput online solid phase extraction - Liquid chromatography - Tandem mass spectrometry method for the detection of tetrodotoxin in human urine.

Tetrodotoxin (TTX) is an extremely potent paralytic toxin responsible for yearly illness and death around the world. A clinical measurement is necessary to confirm exposure because symptoms of TTX intoxication cannot be distinguished from other paralytic toxins. Our group has developed an online solid phase extraction hydrophilic interaction liquid chromatography (HILIC) method for the analysis of TTX in human urine with tandem mass spectrometry.

Detection of human exposure to saxitoxin and neosaxitoxin in urine by online-solid phase extraction-liquid chromatography-tandem mass spectrometry.

Saxitoxin (STX) and neosaxitoxin (NEO) are potent neurotoxins that cause paralytic shellfish poisoning (PSP). PSP typically occurs through the ingestion of bivalve shellfish that have consumed toxin producing dinoflagellates. Due to initial presentation of symptoms being nonspecific, a clinical measurement is needed to confirm exposure to these toxins.

Comparison of two automated solid phase extractions for the detection of ten fentanyl analogs and metabolites in human urine using liquid chromatography tandem mass spectrometry.

Two types of automated solid phase extraction (SPE) were assessed for the determination of human exposure to fentanyls in urine. High sensitivity is required to detect these compounds following exposure because of the low dose required for therapeutic effect and the rapid clearance from the body for these compounds. To achieve this sensitivity, two acceptable methods for the detection of human exposure to seven fentanyl analogs and three metabolites were developed using either off-line 96-well plate SPE or on-line SPE.

Comparison of high-resolution and tandem mass spectrometry for the analysis of nerve agent metabolites in urine.

Rationale: Although use is prohibited, concerns remain for human exposure to nerve agents during decommissioning, research, and warfare. High-resolution mass spectrometry (HRMS) was compared to tandem mass spectrometry (MS/MS) analysis for the quantitation of five urinary metabolites specific to VX, Russian VX, soman, sarin and cyclosarin nerve agents. The HRMS method was further evaluated for qualitative screening of metabolites not included in the test panel.

High Throughput Analysis of Chiral Compounds Using Capillary Electrochromatography (CEC) and CEC-Mass Spectrometry with Cellulose Based Stationary Phases.

To fulfill the ever growing demand for rapid chiral analysis, this research presents an approach for highthroughput enantiomeric separations and sensitive detection of model chiral analytes using capillary electrochromatography (CEC) with UV and MS detection. This was achieved utilizing a short 7 cm CEC columns packed with cellulose tris (3,5-dimethyl-phenylcarbamate) (CDMPC) or sulfonated cellulose tris (3,5-dimethylphenylcarbamate) (CDMPC-SO) chiral stationary phases (CSPs) applying outlet side injections in CEC-UV. The separation performance was compared between CDMPC and CDMPC-SO CSPs for rapid enantio-separation in CEC-UV mode.

Glenoid screw position in the Encore Reverse Shoulder Prosthesis: an anatomic dissection study of screw relationship to surrounding structures.

Background: Fixation of the baseplate to the glenoid for the Reverse Shoulder Prosthesis (DJO Surgical, Austin, TX, USA) requires secure screw purchase to avoid excessive micromotion and baseplate failure. The best screw length for fixation is unknown. In addition, excessively long screws or a plunge of the drill bit during baseplate insertion could injure surrounding structures.

A novel positively charged achiral co-monomer for β-cyclodextrin monolithic stationary phase: improved chiral separation of acidic compounds using capillary electrochromatography coupled to mass spectrometry.

The work presented here demonstrates the incorporation of vinylbenzyl trimethylammonium (VBTA) as a novel positively charged achiral co-monomer to a glycidyl methacrylate-beta cyclodextrin (GMA/β-CD) based monolith, providing anion exchange sites with reversed electroosmotic flow (EOF) for capillary electrochromatography (CEC). The monolithic phases, GMA/β-CD-VBTA and GMA/β-CD (without co-monomer) were characterized by scanning electron microscopy, optical microscopy, pressure drop/flow-rate curves and nitrogen adsorption analysis. After optimizing the stationary phase and mobile phase parameters, chiral separations of 41 pairs of structurally diverse anionic chiral analytes were compared individually using the GMA/β-CD-VBTA and GMA/β-CD monolithic columns.

Development of a fritless packed column for capillary electrochromatography-mass spectrometry.

A novel procedure was developed for the fabrication of a fritless packed column for the coupling of capillary electrochromatography (CEC) to mass spectrometry (MS). The process involved the formation of internal tapers on two separate columns. Once the internal tapers are formed and the columns are packed, the untapered ends of each column were joined together by a commercially available connector.

Sulfated and sulfonated polysaccharide as chiral stationary phases for capillary electrochromatography and capillary electrochromatography-mass spectrometry.

The applications of polysaccharide phenyl carbamate derivatives as chiral stationary phases (CSPs) for capillary electrochromatography (CEC) are often hindered by longer retention times, especially using a normal-phase (NP) eluent due to very low electroosmotic flow (EOF). Therefore, in this study, we propose an approach for the aforementioned problems by introducing two new types of negatively charged sulfate and sulfonated groups for polysaccharide CSPs. These CSPs were utilized to pack CEC columns for enantioseparation with a NP eluent.

Optimized separation of beta-blockers with multiple chiral centers using capillary electrochromatography-mass spectrometry.

This work focuses on the simultaneous analysis of beta-blockers with multiple stereogenic centers using capillary electrochromatography-mass spectrometry (CEC-MS) with a vancomycin stationary phase. The critical mobile phase variables (composition of organic solvents, acid/base ratios) as well as column temperature and electric field strength, effecting enantioresolution and analysis time were first optimized sequentially. Next, to achieve global optimum a multivariate D-optimal design was used.

UHMWPE wear debris upregulates mononuclear cell proinflammatory gene expression in a novel murine model of intramedullary particle disease.

Background: We examined the effects of ultra-high molecular weight polyethylene (UHMWPE) particles on mononuclear cell proinflammatory gene expression in a novel murine model. We hypothesized that mononuclear cell gene transcription of tumor necrosis factor-alpha (TNF-alpha), interleukin-1 beta (IL-1beta), interleukin-6 (IL-6) and macrophage chemoattractant protein-1 (MCP-1) would be upregulated by the addition of polyethylene particles in this murine intramedullary rod model.

Material And Methods: The model involved a stainless steel Kirschner wire inserted retrograde with a line-to-line fit in bilateral femora of C57bl/6 mice.