scholarly journals Comparative Analysis of ELISA Immunoassay and LC-QTOF for Opiate Screening

2020 ◽  
Vol 44 (4) ◽  
pp. 410-413
Author(s):  
Dickson Kennedy ◽  
Mata Dani
Keyword(s):  
Mass Spectrometry ◽  
Comparative Analysis ◽  
Screening Method ◽  
Enzyme Linked Immunosorbent Assay ◽  
Blood Samples ◽  
Flight Mass Spectrometry ◽  
Low Concentrations ◽  
Postmortem Blood ◽  
Targeted Screening ◽  
Liquid Chromatography Tandem Mass

Abstract A comparative analysis of enzyme-linked immunosorbent assay (ELISA) and quadrupole time-of-flight mass spectrometry (LC-QTOF) for the detection of opioids in blood samples is presented. The Orange County Crime Lab (OCCL) was concerned that the opioid drug class was not accurately detected at low concentrations due to the use of LC-QTOF as a non-targeted screening method for multiple classes of drugs. In order to investigate this issue, 968 ante-mortem and postmortem blood samples were analyzed by ELISA for the presence of the following opioids: morphine, morphine-glucuronide, codeine, codeine-glucuronide, hydrocodone, hydromorphone, hydromorphone-glucuronide, oxycodone, oxymorphone and oxymorphone-glucuronide. All samples had been previously analyzed by LC-QTOF. Overall, 84 samples tested positive for opioids. Discrepant samples between ELISA and LC-QTOF were analyzed by a liquid chromatography tandem mass spectrometry confirmation method in order to determine the true composition of the sample. Upon review of the discrepant samples, no forensically relevant concentration of opioids was missed by LC-QTOF. Thus, the ability of the OCCL’s LC-QTOF screening method was verified to detect opioids at low concentrations.

Comparing ELISA and LC-MS/MS: A Simple, Targeted Postmortem Blood Screen

2021 ◽  
Author(s):  
Dina M Swanson ◽  
Julia M Pearson ◽  
Theresa Evans-Nguyen
Keyword(s):  
Mass Spectrometry ◽  
Sample Preparation ◽  
Limit Of Detection ◽  
Screening Method ◽  
Chemical Properties ◽  
Forensic Toxicology ◽  
Enzyme Linked Immunosorbent Assay ◽  
Minimal Sample ◽  
Elisa Testing ◽  
Postmortem Blood

Abstract A comprehensive screening method that is specific, accurate, and customizable is necessary in any forensic toxicology laboratory. Most laboratories utilize some form of immunoassay testing as it is reliable and sensitive with minimal sample preparation and is relatively inexpensive to simultaneously screen for multiple classes of drugs with different chemical properties. However, accessibility to more specific technology and instrumentation such as mass spectrometry has increased and therefore using immunoassay as the screening method of choice may be revisited. A screening method for 42 drugs in postmortem blood was developed and validated following the Organization of Scientific Area Committees for Forensic Science (OSAC) guidelines for toxicology method validation. The method was developed using minimal sample preparation of postmortem blood consisting only of a protein precipitation. Only two internal standards were used which greatly reduces the cost of implementing this method. Limit of detection (LOD), interference studies, processed sample stability and ion suppression/enhancement were examined. Additionally, over 100 case samples were analyzed by both the current enzyme linked immunosorbent assay (ELISA) testing procedure and the proposed liquid chromatography tandem mass spectrometry (LC-MS/MS) screening method. The comparison determined that the LC/MS-MS method performed as well as or better than the ELISA in nearly all cases. The ability to add additional target drugs increases the laboratory’s scope of analysis as well. This method is ideal for forensic laboratories wishing to improve screening while working within budget constraints.

scholarly journals Metabolic Profiling of Pitaya (Hylocereus polyrhizus) during Fruit Development and Maturation

Molecules ◽  
2019 ◽  
Vol 24 (6) ◽  
pp. 1114 ◽  
Author(s):  
Yawei Wu ◽  
Juan Xu ◽  
Yizhong He ◽  
Meiyan Shi ◽  
Xiumei Han ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Metabolic Profiling ◽  
Developmental Stages ◽  
Principal Component ◽  
Nutrient Content ◽  
Flight Mass Spectrometry ◽  
Potential Biomarker ◽  
Fruit Samples ◽  
Liquid Chromatography Tandem Mass ◽  
Hylocereus Polyrhizus

Pitaya (Hylocereus polyrhizus) has attracted much interest from consumers as it is a novelty fruit with high nutrient content and a tolerance to drought stress. As a group of attractive pigment- and health-promoting natural compounds, betalains represent a visual feature for pitaya fruit quality. However, little information on the correlation between betalains and relevant metabolites exists so far. Currently, color (Commission International del’Eclairage, CIE) parameters, betalain contents, and untargeted metabolic profiling (gas chromatography-time-of-flight-mass spectrometry, GC–MS and liquid chromatography tandem mass spectrometry, LC–MS) have been examined on ‘Zihonglong’ fruits at nine different developmental stages, and the variation character of the metabolite contents was simultaneously investigated between peel and pulp. Furthermore, principal component analysis (PCA) and partial least-squares discriminant analysis (PLS-DA) were used to explore metabolite profiles from the fruit samples. Our results demonstrated that the decrease of amino acid, accompanied by the increase of sugars and organic acid, might contribute to the formation of betalains. Notably, as one of four potential biomarker metabolites, citramalic acid might be related to betalain formation.

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