Sample preparation extraction

Factors Affecting Extraction Yield in SC-CO2 Extraction Sample Preparation... 

A system based on microdialysis coupled with flow-injection chemiluminescence detection allows for direct sampling of unbound drug without extractive sample preparation [72], A similar approach based on continuous ultrafiltration has also been reported [73]. Modifications designed to overcome challenges of low solubility and high-non-specific binding in the ultrafiltration approach have also been described [74]. 

Because of these distinct advantages over classical extractive sample preparation techniques, it is easy to understand why SPME has become one of the most popular sample preparation techniques for water analysis. Numerous monographs and reviews document this great popularity and discuss in detail the theory and practice of SPME,102 103 as well as applications in the field of environmental analysis104-105 and speciation analytics.106-107... 

Overview of Extraction/Sample Preparation Techniques Derived from or Related to SPME... 

In static headspace extraction, sample preparation for liquid samples is usually quite simple—most often, the sample can just be transferred to the headspace sample vial and sealed immediately following collection of sample to minimize storage and handling losses [13],... 

Samples rarely come in a form that can be injected directly into the instrument some form of sample preparation usually is required. Sample preparation includes any manipulation of the sample prior to analysis, including techniques such as weighing, dilution, concentration, filtration, centrifugation, and liquid- or solid-phase extraction. Sample preparation can be performed either on-line or off-line, but it is usually performed offline. Off-line preparation can be time-consuming and tedious, and the more steps that are required, the more susceptible the analytical method is to operator error and irreproducibility. 

Tong, X.S. et al., High-throughput pharmacokinetics screen of VLA-4 antagonists by LC/MS/MS coupled with automated solid-phase extraction sample preparation, J. Pharm. Biomed. Anal., 35(4), 867, 2004. 

Bai Y, Glatz CE (2003) Bioprocess considerations for expanded-bed chromatography of cmde canola extract sample preparation and adsorbent reuse. Biotechnol Bioeng 81 775-782. 

In Chapter 18, we described solvent extraction and solid-phase extraction sample preparation methods, which are applicable to GC analyses as well as others. A convenient way of sampling volatile samples for GC analysis is the technique of head-space analysis. A sample in a sealed vial is equilibrated at a fixed temperature, for example, for 10 min, and the vapor in equilibrium above the sample is sampled and injected into the gas chromatograph. A typical 20-mL glass vial is capped with a silicone rubber septum lined with polytetrafluoroethylene (PTFE). A syringe needle can be inserted to withdraw a 1-mL portion. Or the pressurized vapor is allowed to expand into a 1-mL sample loop at atmospheric pressure, and then an auxiliary carrier gas carries the loop contents to the GC loop injector. Volatile compounds in solid or liquid samples can be determined at parts per million or less. Pharmaceutical tablets can be dissolved in a water-sodium sulfate solution... 

Application of Solid-Phase Extraction Sample Preparation Before MALDI-MS 1355... 

Taking advantage of its high separation strength, a combination of SEC with MS enhances the capability of MS and makes it possible for the analysis of coal liquids. SEC can be used as a coal liquid sample pretreatment method prior to GC-MS. For SEC, 1-methyl-2-pyrrolidinone (NMP) is often used as eluent. Analytical result for a coal liquefaction extract sample prepared from SEC by GC-MS showed that only the pentane-soluble components could be analyzed [16] the larger aromatic molecules identified by SEC to be present were lost in the GC column. The molecular weight of the aromatics analyzed in the coal liquids were up to 352 with very few aliphatics. 

Fig. 3 Schematic workflow of porous silicon-ISET iMALDI top (I), antibody-immobilized porous silicon was used to capture the antigen angiotensin I bottom (II), RP solid-phase extraction sample preparation protocol on the ISET chip was used to purify and reconcentrate the elution followed by MALDI MS deteetion (Yan et al. 2011) (Reprinted with permission from Analytical Chemistry, 83, Yan, Ahmad-Tajudin, Bengtsson, Xiao, Laurell, Ekstrom, Noncovalent antibody immobilization on porous silieon eombined with miniaturized solid-phase extraction SPE) for array based immunoMALDI assays, 4942-4948. Copyright 2011 Ameriean Chemieal Society)...

An internal standard (IS) is used primarily to monitor the reliability of extraction, sample preparation, chromatographic, and instrumentation procedure. The use of an IS is strongly recommended if the sample preparation method consists of several steps. In such a case a known amount of an internal standard would be added to the sample at an early stage on the assumption that the internal standard... 

Sampling period Reference Location Species Extraction-sample preparation Limit of detection/ quantification Results/remarks validation PAHs measured... 

Atotal number of 73 target compounds comprising 18 PCBs, 16 OCRs, 14BFRs and 25 PAHs can be determined using a common liquid extraction sample preparation with a short silica minicolumn clean-up. Very low MQLs are achieved for all target analytes in the range from 0.005 to 1 ig/kg for fish muscle tissue and 0.05-10 pg/kg for fish feed. The recoveries in both matrices are in the range of 70-120%. 

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