Modified liquid junction interface for nonaqueous capillary electrophoresis-mass spectrometry

Jussila, Matti; Sinervo, Kai; Porras, Simo P.; Riekkola, Marja‐Liisa

doi:10.1002/1522-2683(20000901)21:15<3311::aid-elps3311>3.0.co;2-n

Cited by 25 publications

(6 citation statements)

References 24 publications

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“…However, sample preparation has often been the rate-limiting step; because of its lipophilic nature methadone is difficult to extract from blood or plasma. A variety of preparation procedures have been reported including nonaqueous electrophoresis-MS (145) and solid-phase microextraction (SPME) (146). Unless provision is made for the supervised consumption of methadone by drug addicts, plasma methadone monitoring is recommended to monitor compliance (142,147).…”

Section: Methadone Measurementmentioning

confidence: 99%

Characterization of Methadone Overdose: Clinical Considerations and the Scientific Evidence

Wolff¹

2002

Therapeutic Drug Monitoring

105

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Overdosing with methadone is a growing phenomenon in Britain and other countries due to the increase in prescription and the availability of this compound. Little is known of the circumstances surrounding methadone death due to some extent to the difficulty of defining drug-related death and also the difficulty of collecting clinical and biographical data in a predominantly illegal and marginal milieu. However, the evidence points to highest risk at night (to this end manifestations of its toxicity often go unrecognized) in those whose usual tolerance has been reduced and occurring some considerable time after ingestion. Further investigations are needed to elucidate fully the mechanism and spectrum of methadone overdose. Death from methadone is eminently preventable more so because of the long-term nature of the clinical sequelae. Indeed the key issue with methadone that sets it apart from other opioids is its potential for delayed toxicity. Consequently steps should be taken to disseminate the salient facts to all those who come into contact with the drug.

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Section: Methadone Measurementmentioning

confidence: 99%

Characterization of Methadone Overdose: Clinical Considerations and the Scientific Evidence

Wolff¹

2002

Therapeutic Drug Monitoring

105

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“…Sheath‐flow interfaces can be categorized based on the location of the mixing of effluent and sheath liquid 18. In the liquid junction design a make‐up solution, which serves similar purposes to the sheath liquid, is added to the CE effluent at a junction between the separation capillary terminus and the entrance to the channel of the electrospray emitter 19–22. In the more common coaxial design, found in many commercial CE‐ESI‐MS systems 23, the sheath liquid surrounds the capillary terminus and mixing of the two solutions occurs within the Taylor cone, immediately before ionization and desolvation 17, 24.…”

Section: Introductionmentioning

confidence: 99%

Decoupling CE and ESI for a more robust interface with MS

et al. 2010

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An interface for CE-ESI-MS that decouples both the electrical and the solution flow rate requirements of the separation and ionization processes is presented. The interface uses a tapered and beveled stainless steel hollow needle surrounding the separation capillary terminus so that the inside of the electrode acts as the CE outlet vial and the outside tip acts as the electrospray emitter. No capillary pre-treatment is required, enabling the use of capillaries with any type of surface modification. A chemical modifier solution is introduced through a second capillary connected to the needle via a tee junction and can be used to improve the compatibility of the CE BGE with electrospray. The flow rate of modifier solution can be as low as 0.1 microL/min, much less than that in a typical sheath-flow interface, thus minimizing dilution of the CE effluent in order to maximize sensitivity. The presence of the modifier solution also allows the use of neutral-coated capillaries for protein analysis by CE-MS without using an assisting pressure, despite the absence of EOF under these conditions. The interface is easily integrated into a commercial CE instrument, such that all operations can be carried out by the automated controls. Compared with a commercial sheath-flow CE-MS interface operating under optimized conditions, LODs for amino acids were, on average, improved fivefold.

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“…Jussila et al used NACE-ESI-ion trap MS for the detection of methadone, pentazocine, levorphanol, dihydrocodeine, and morphine [38]. The study introduced a modified type of interface, where the ESI spray capillary is extremely thin so that its inlet end is inserted into the CE capillary.…”

Section: Capillary Zone Electrophoresismentioning

confidence: 99%