| 1. |
- Abdel-Rehim, Mohamed, et al.
(författare)
-
Microextraction approaches for bioanalytical applications : An overview
- 2020
-
Ingår i: Journal of Chromatography A. - : Elsevier B.V.. - 0021-9673 .- 1873-3778. ; 1616
-
Tidskriftsartikel (refereegranskat)abstract
- Biological samples are usually complex matrices due to the presence of proteins, salts and a variety of organic compounds with chemical properties similar to those of the target analytes. Therefore, sample preparation is often mandatory in order to isolate the analytes from troublesome matrices before instrumental analysis. Because the number of samples in drug development, doping analysis, forensic science, toxicological analysis, and preclinical and clinical assays is steadily increasing, novel high throughput sample preparation approaches are calling for. The key factors in this development are the miniaturization and the automation of the sample preparation approaches so as to cope with most of the twelve principles of green chemistry. In this review, recent trends in sample preparation and novel strategies will be discussed in detail with particular focus on sorptive and liquid-phase microextraction in bioanalysis. The actual applicability of selective sorbents is also considered. Additionally, the role of 3D printing in microextraction for bioanalytical methods will be pinpointed.
|
|
| 2. |
- El-Beqqali, Aziza, et al.
(författare)
-
Fast and sensitive environmental analysis utilizing microextraction in packed syringe online with gas chromatography-mass spectrometry - Determination of polycyclic aromatic hydrocarbons in water
- 2006
-
Ingår i: Journal of Chromatography A. - : Elsevier BV. - 0021-9673 .- 1873-3778. ; 1114:2, s. 234-238
-
Tidskriftsartikel (refereegranskat)abstract
- A new sensitive, selective, fast and accurate technique for online sample preparation was developed. Microextraction in a packed syringe (MEPS) is a new miniaturised, solid-phase extraction (SPE) technique that can be connected online to GC or LC without any modifications. In MEPS approximately 1 mg of the solid packing material is inserted into a syringe (100-250 ml) as a plug. Sample preparation takes place on the packed bed. The bed can be coated to provide selective and suitable sampling conditions. The new method is very promising. It is very easy to use, fully automated, of low cost and rapid in comparison with previously used methods. The determination of polycyclic hydrocarbons (PAHs) in water was performed using MEPS as sample preparation method online with gas chromatography and mass spectrometry (MEPS-GC-MS). The results from MEPS as sample preparation were compared with other techniques such as stir bar sorptive extraction (SBSE) and solid-phase microextraction (SPME). The method was validated and the standard curves were evaluated by the means of quadratic regression and weighted by inverse of the concentration: 1/x for the calibration range 5-1000 ng/L. The MEPS applied polymer (silica-C8) could be used more than 400 times before the syringe was discarded. The extraction recovery was about 70%. The results showed close correlation coefficients (R > 0.998) for all analytes in the calibration range studied. The accuracy of MEPS-GC-MS was between 90 and 113% and the inter-day precision (n = 3 days), expressed as the relative standard deviation (RSD%), was 8-16%. MEPS reduced the handling time by 30 and 100 times compared to SPME and SBSE, respectively.
|
|
| 3. |
- Elmongy, Hatem, et al.
(författare)
-
Online post-column solvent assisted and direct solvent-assisted electrospray ionization for chiral analysis of propranolol enantiomers in plasma samples
- 2015
-
Ingår i: Journal of Chromatography A. - : Elsevier BV. - 0021-9673 .- 1873-3778. ; 1418, s. 110-118
-
Tidskriftsartikel (refereegranskat)abstract
- An Online post-column solvent-assisted ionization (OPSAI) method was developed for enhancing the ionization of the beta-blocker propranolol utilizing normal phase LC-MS/MS. Solvent-assisted electrospray ionization (SAESI) was studied by the introduction of the assistant solvents A: 0.5% Formic acid in Isopropanolol, B: 0.5% Formic acid in lsopropanolol-Water (1:1), and C: 0.5% Formic acid in water into the electrospray ionization chamber using a spray needle. Analyte molecules can be directly ionized by the aid of the assistant solvent spray. Both methods were applied to the chiral separation of propranolol enantiomers using normal phase analysis on cellulose-based chiral column. Interestingly, both methods are easy to handle and offer a wide range of assistant solvents that can be used in order to gain the optimum ionization of the analyte molecules. The both methods considerably improved the analyte signal and the peak area greatly increased. The propranolol average signal-to-noise (S/N) ratio was enhanced from 26 +/- 1 and 42 +/- 1 to 2341 +/- 61 and 1725 +/- 29 for R-propranolol and S-propranolol, respectively, when the post-column solvent method (OPSAI) was used with isopropanol-assistant solvent (A). While in case of solvent-assisted electrospray ionization method (SAESI) signal was enhanced from 26 +/- 1 and 42 +/- 1 to 2223 +/- 72 and 2155 +/- 58 for R-propranolol and S-propranolol, respectively, with water as an assistant solvent. The limit of detection was 10 ng/mL and the method was linear in the range 50-2000 ng/mL. The NPLC-MS method was applied for the determination of propranolol enantiomers in human plasma after microextraction by packed C18 sorbent.
|
|
| 4. |
- Iadaresta, Francesco, et al.
(författare)
-
Application of graphitic sorbent for online microextraction of drugs in human plasma samples
- 2015
-
Ingår i: Journal of Chromatography A. - : Elsevier BV. - 0021-9673 .- 1873-3778. ; 1422, s. 34-42
-
Tidskriftsartikel (refereegranskat)abstract
- In the present work a new sorbent based on graphitized carbon (CarbonX (R) COA) was evaluated in microextraction by packed sorbent (MEPS) for extraction of lidocaine and ropivacaine from human plasma samples. The new graphitic sorbent showed high recoveries of lidocaine and ropivacaine compared to C18 sorbent In the present study the G-MEPS (syringe packed with graphitic sorbent) was connect online with liquid chromatography tandem mass spectrometry (LC-MS/MS). In order to obtain a fast and reliable method different factors affecting MEPS performance were investigated. The extraction efficiency of the graphitic sorbent was compared with silica-based sorbents used in MEPS. The G-MEPS was also evaluated for reuse (50-100 times). The recoveries of lidocaine and ropivacaine from plasma samples were 79% and 82%; respectively. The method was validated according to FDA (Food and Drug Administration) guideline for bioanalytical method validation. Linearity was assessed in the range 5-2000 nmol/L, with coefficient of determination r(2) > 0,995 (n=3) for lidocaine and r(2) > 0.997 (n=3) for ropivacaine. The lower limit of quantification (LLOQ) was 5 nmol/L and the limit of detection (LOD) was 1 nmol/L for studied analytes in plasma samples. For both analytes considered in this study the accuracy values in plasma samples were ranged from 86% to 113%. The Inter-day precisions, expressed as relative standard deviation (%RSD), at three different concentrations (QC-samples) ranged from 8% to 9% for lidocaine, and from 4% to 11% for ropivacaine.
|
|
| 5. |
- Moein, Mohammad Mahdi, et al.
(författare)
-
A needle extraction utilizing a molecularly imprinted-sol-gel xerogel for on-line microextraction of the lung cancer biomarker bilirubin from plasma and urine samples
- 2014
-
Ingår i: Journal of Chromatography A. - : Elsevier BV. - 0021-9673 .- 1873-3778. ; 1366, s. 15-23
-
Tidskriftsartikel (refereegranskat)abstract
- In the present work, a needle trap utilizing a molecularly imprinted sal-gel xerogel was prepared for the on-line microextraction of bilirubin from plasma and urine samples. Each prepared needle could be used for approximately one hundred extractions before it was discarded. Imprinted and non-imprinted sol-gel xerogel were applied for the extraction of bilirubin from plasma and urine samples. The produced molecularly imprinted sol-gel xerogel polymer showed high binding capacity and fast adsorption/desorption kinetics for bilirubin in plasma and urine samples. The adsorption capacity of molecularly imprinted sal-gel xerogel polymer was approximately 60% higher than that of non-imprinted polymer. The effect of the conditioning, washing and elution solvents, pH, extraction time, adsorption capacity and imprinting factor were investigated. The limit of detection and the lower limit of quantification were set to 1.6 and 5 nmol L-1, respectively using plasma or urine samples. The standard calibration curves were obtained within the concentration range of 5-1000 nmol L-1 in both plasma and urine samples. The coefficients of determination values (R-2) were >= 0.998 for all runs. The extraction recovery was approximately 80% for BR in the human plasma and urine samples.
|
|
| 6. |
|
|
| 7. |
- Moein, Mohammad Mahdi, et al.
(författare)
-
On-line detection of hippuric acid by microextraction with a molecularly-imprinted polysulfone membrane sorbent and liquid chromatography-tandem mass spectrometry
- 2014
-
Ingår i: Journal of Chromatography A. - : Elsevier BV. - 0021-9673 .- 1873-3778. ; 1372, s. 55-62
-
Tidskriftsartikel (refereegranskat)abstract
- Destruction of sorbents during consecutive extractions using the microextraction by packed sorbent (MEPS) technique is a serious problem. In MEPS the complex matrix such as plasma and blood can affect the sorbent physical properties and the sorbent can be deteriorated after handling of few samples. To overcome this problem, the surface of a polysulfone membrane (PSM) was modified by a molecularly imprinted sol-gel and utilized for online extraction of a lung cancer biomarker, hippuric acid (HA), in biological matrices. The molecularly imprinted polymer membrane provided fast, sensitive, selective and robust sample preparation method for HA in biological fluids. In addition, MIP membrane could be used for up to 50 extractions without a significant change in extraction recovery. To achieve the best results, the parameters that influenced the extraction efficiency were thoroughly investigated. Moreover, for evaluating the performance of the molecularly imprinted sol-gel membrane (MISM), a non-molecularly imprinted sol-gel membrane (NISM) as a blank was prepared. The limits of detection CLOD) and quantification (LOQ) for HA in both plasma and urine samples were 0.30 nmol L-1 and 1.0 nmol L-1, respectively. Standard calibration curves were obtained over the range of 1-1000 nmol L-1 for HA in plasma and urine samples. The coefficients of determination (R2) were ≥ 0.997. The extraction recoveries of HA from human plasma and urine samples were higher than 91%. The precision values for HA in plasma and urine samples were 2.2-4.8% and 1.1-6.7%, respectively.
|
|
| 8. |
- Ruokonen, Suvi-Katriina, et al.
(författare)
-
Distribution of local anesthetics between aqueous and liposome phases
- 2017
-
Ingår i: Journal of Chromatography A. - : Elsevier BV. - 0021-9673 .- 1873-3778. ; 1479, s. 194-203
-
Tidskriftsartikel (refereegranskat)abstract
- Liposomes were used as biomimetic models in capillary electrokinetic chromatography (EKC) for the determination of distribution constants (K-D) of certain local anesthetics and a commonly used preservative. Synthetic liposomes comprised phosphatidylcholine and phosphatidylglycerol phospholipids with and without cholesterol. In addition, ghost liposomes made from red blood cell (RBC) lipid extracts were used as pseudostationary phase to acquire information on how the liposome composition affects the interactions between anesthetics and liposomes. These results were compared with theoretical distribution coefficients at pH 7.4. In addition to 25 degrees C, the distribution constants were determined at 37 and 42 degrees C to simulate physiological conditions. Moreover, the usability of five electroosmotic flow markers in liposome (LEKC) and micellar EKC (MEKC) was studied. LEKC was proven to be a convenient and fast technique for obtaining data about the distribution constants of local anesthetics between liposome and aqueous phase. RBC liposomes can be utilized for more representative model of cellular membranes, and the results indicate that the distribution constants of the anesthetics are greatly dependent on the used liposome composition and the amount of cholesterol, while the effect of temperature on the distribution constants is less significant.
|
|
