geoscience.net logo
+ Resolve Article
+ Follow Us
Follow on FacebookFollow on Facebook
Follow on TwitterFollow on Twitter

+ Translate
+ Subscribe to Site Feed
GeoScience Most Shared ContentMost Shared Content

Head-column field-amplified sample stacking in binary system capillary electrophoresis. 2. Optimization with a preinjection plug and application to micellar electrokinetic chromatography


, : Head-column field-amplified sample stacking in binary system capillary electrophoresis. 2. Optimization with a preinjection plug and application to micellar electrokinetic chromatography. Analytical Chemistry 70(3): 540-548

In capillary electrophoresis, head-column field-amplified sample stacking (FASS) provides the largest sensitivity enhancement of all electrokinetic concentration techniques (Zhang, C.-X.; Thormann, W. Anal. Chem. 1996, 68, 2523). Application of head-column FASS to the analysis of closely related opioids by capillary zone electrophoresis in binary systems with ethylene glycol is described. It is shown that sample condensation is further increased about 2-fold by introduction of a preinjection plug, i.e., introduction of a short solution plug of high conductivity, high pH, and high viscosity at the capillary tip prior to injection. The preinjection plug acts as a temporary trap for solutes. Its effective length is shown to be limited to a few millimeters. The highest sample stacking efficiency in head-column FASS is obtained via optimization of the electric field strength and the effective electrophoretic mobility of the solutes within the sample and the adjacent zones and is thus strongly dependent on the compositions of both the sample matrix and the preinjection plug. Binary sample solutions of low conductivity and low viscosity containing small amounts of a weak acid are demonstrated to be most effective for the stacking of positively charged opioids. The procedure developed for capillary zone electrophoresis of opioids in binary systems with ethylene glycol and UV absorbance detection is documented to provide a 3 orders of magnitude sensitivity enhancement, exhaustive sample injection from an external reservoir of up to 20 microL (i.e., from a volume that is more than 20-fold the volume of the capillary employed), and a lowest detectable concentration of 0.1 ng/mL (S/N = 3). Using internal calibration, typical intraday and interday imprecisions of solute concentrations between 3 and 10 ng/mL and between 0.5 and 1.5 ng/mL are < or = 5% and < or = 15%, respectively. The stacking approach has been successfully applied to the analysis of dihydrocodeine in extracts of 20 microL of human plasma and is shown to permit the precise (imprecision < or = 10%) determination of dihydrocodeine plasma levels of pharmacological interest (3-300 ng/mL or 10-1000 nM). Furthermore, using a modified protocol for micellar electrokinetic chromatography, head-column FASS is shown to provide a 400-fold sensitivity enhancement for a number of opioids. The stacking procedure is based on insertion of a surfactant-free preinjection plug and temporary application of reversed voltage after electroinjection.

US$29.90

PMID: 9470486


Other references

Ovsyannikov, M.I., 1967: Healing in the middle ear of animals after a radical operation and the use of some plastic materials for the obliteration of the tympanic bulla. Experimentation with 82 rabbits and guinea pigs showed that pedicled grafts are the most reliable plastic material for the obliteration of the cavity of tympanic bulla in comparison with free muscular, bone, cartilaginous transplants and bioplasti...

Rickenberg, H.V., 1960: The intracellular accumulation of galactose and glucose by Earles strain L tissue culture cells. Bact Proc: 2-123

Davis, J.G.; Lowrance, R.R.; Newton, G.L.; Vellidis, G.; Dove, R., 1995: Designing riparian buffer systems for utilization and treatment of effluent. The feasibility of using grass riparian zone buffer systems to use and treat agricultural effluent was investigated in Georgia, USA. The riparian systems tested included a 32.8 ft grass-65.6 ft riparian forest, a 65.6 ft grass-32.ft riparian fores...

Neave, Russell., 2003: Terek sandpiper at Heybridge GP, Maldon - 25th-29th August 2002 the third Essex record. Essex Bird Report. December; 2002: 139-140

Baribaud, F.; Wirth, S.; Maillard, I.; Valsesia, S.; Acha-Orbea, H.; Diggelmann, H., 2001: Identification of key amino acids of the mouse mammary tumor virus superantigen involved in the specific interaction with T-cell receptor V(beta) domains. Mouse mammary tumor virus (MMTV) is a retrovirus encoding a superantigen that is recognized in association with major histocompatibility complex class II by the variable region of the beta chain (V(beta)) of the T-cell receptor. The C-terminal 30...

Krämer, B.K.; Ress, K.M.; Erley, C.M.; Risler, T., 1991: Effects of beta-blockade on urinary albumin excretion in normal subjects. Urinary albumin excretion is a marker of renal damage in diabetic or hypertensive patients and a reduction of albuminuria during beta-blockade has been demonstrated in several studies. In the present study the effects of beta-blockade with drugs k...

Taylor, B.E.; Brooks, M.J., 1995: Predictability of water level in a Carolina bay A baseline for interpreting the activities of modern copepods and prehistoric humans. Bulletin of the Ecological Society of America 76(2 SUPPL PART 2): 261

Wilson Alice Evelyn, 1937: Erosional intervals indicated by contacts in the vicinity of Ottawa, Ontario. Transactions of the Royal Society of Canada = Memoires de la Societe Royale du Canada: ages 45-60. 1937.

Lecchini, D.; Planes, S.; Galzin, R., 2007: The influence of habitat characteristics and conspecifics on attraction and survival of coral reef fish juveniles. In marine species with a pelagic larval stage, search behavior and selection of a suitable reef habitat can maximize the settlement success of recently settled juveniles and their subsequent performance (growth and survival of juveniles). Our obj...

Hexana, W.; D.C.ning, P.; Jali, S.; Van der Westhuizen, R.; Brack, B.; van Houwelingen, A.; Nel, R., 2014: Comprehensive two-dimensional GC for the analysis of low-molecular-weight oxygenates in three different matrices from a petrochemical pilot plant using a single calibration. A method using comprehensive (2) DGC with flame ionisation detection was developed to quantify 17 low-molecular-weight oxygenates in three different matrices, namely water, oil and gas, using a single calibration. The method was required for the p...