On-Line Immunoaffinity Extraction-Coupled Column Capillary Liquid Chromatography/Tandem Mass Spectrometry: Trace Analysis of LSD Analogs and Metabolites in Human Urine
Analytical Chemistry January 1, 1996 DOI: 10.1021/ac950763i via OpenAlex
Summary
AI-generated from the abstractAn on-line immunoaffinity extraction-coupled column capillary liquid chromatography/tandem mass spectrometry method was developed to detect LSD and its analogs and metabolites in human urine. The system uses three columns and allows direct analysis of diluted urine without pretreatment, eliminating sample handling steps. Concentrations as low as 2.5 parts per trillion of LSD and several analogs were detected in spiked human urine, which is 20-fold lower than the previous limit of detection using solid phase extraction and liquid chromatography/tandem mass spectrometry. The method was also applied to urine specimens from LSD users.
Study at a glance
| Characteristics | Method development and evaluation Peer reviewed |
|---|---|
| Population | Spiked human urine and urine specimens from LSD users |
| Keywords | Tandem mass spectrometry Detection limit Analyte Extraction chemistry Solid phase extraction |
| Citations | 112 |
| Key finding | The method detected LSD and its analogs at concentrations as low as 2.5 parts per trillion in spiked human urine, a 20-fold improvement over the previous limit of detection. |
Abstract
An on-line immunoaffinity extraction-coupled column capillary liquid chromatography/tandem mass spectrometry (IAE/LC/LC/MS/MS) method is described. The system involves three columns, a 2.1-mm-i.d. protein G immunoaffinity column with noncovalently immobilized antibody specific to the analytes of interest, a packed capillary trapping column, and a packed capillary analytical column. With use of a short packed capillary trapping column, the protein G column could be operated at flow rates of 2.5-4 mL/min while the packed capillary analytical column was maintained at a flow rate of 3.5 microL/min. Human urine diluted 1:1 with phosphate-buffered saline was pumped directly onto the immunoaffinity column without pretreatment and was analyzed by electrospray mass spectrometry following the column switching process. Sample handling and transfer procedures were eliminated. The system was optimized and evaluated for the determination of LSD, its analogs, and metabolites in spiked human urine at low part-per-trillion (ppt) levels using mass spectrometric detection. LSD-positive human urine specimens from LSD users were also analyzed. Concentrations as low as 2.5 ppt of LSD and several of its analogs were detected in spiked human urine using IAE/LC/LC/MS/MS/. This is 20-fold below our previous limit of detection using solid phase extraction and LC/MS/MS.