Sample Preparation For Chromatography Research Articles

Testing the Fundamentals: An Examination of Your Extraction Knowledge

As I write this, I’m also grading the final exam from my “Chromatography and Separations” course. We spent approximately the first 75% of the course covering column chromatography, capillary electrophoresis (CE), and field-flow fractionation. The remainder of the course focused on chromatographic sample preparation. The final exam was based on this last section of the course. Some questions make a good review of the fundamentals of various extraction techniques. The basis for these questions may have been discussed in previous iterations of this column, in analytical chemistry textbooks, or in books on chemical separations. I generally give the final exam in my graduate courses as a take-home exam, so you are free to use whatever resources you have available to you. Here’s your opportunity to test yourself, as the answers are provided.

Insights into the structure-performance relationships of extraction materials in sample preparation for chromatography

Sample preparation is one of the most crucial steps in analytical processes. Commonly used methods, including solid-phase extraction, dispersive solid-phase extraction, dispersive magnetic solid-phase extraction, and solid-phase microextraction, greatly depend on the extraction materials. In recent decades, a vast number of materials have been studied and used in sample preparation for chromatography. Due to the unique structural properties, extraction materials significantly improve the performance of extraction devices. Endowing extraction materials with suitable structural properties can shorten the pretreatment process and improve the extraction efficiency and selectivity. To understand the structure-performance relationships of extraction materials, this review systematically summarizes the structural properties, including the pore size, pore shape, pore volume, accessibility of active sites, specific surface area, functional groups and physicochemical properties. The mechanisms by which the structural properties influence the extraction performance are also elucidated in detail. Finally, three principles for the design and synthesis of extraction materials are summarized. This review can provide systematic guidelines for synthesizing extraction materials and preparing extraction devices.

Twenty years of supramolecular solvents in sample preparation for chromatography: achievements and challenges ahead.

Supramolecular solvents (SUPRAS) have progressively become a suitable alternative to organic solvents for sample preparation in chromatographic analysis. The inherent properties of these nanostructured solvents (e.g. different polarity microenvironments, multiple binding sites, possibility of tailoring their properties, etc.) offer multiple opportunities for the development of innovative sample treatment platforms not approachable by conventional solvents. In this review, major achievements attained in the combination SUPRAS-chromatography in the last 20years as well as the challenges that should be addressed in the near future are critically discussed. Among achievements, particular attention is paid to the theoretical and practical knowledge gained that has helped make substantial progress in the area. In this respect, advances in the understanding of the mechanisms involved in SUPRAS formation and SUPRAS-solute interactions driving extractions are discussed, with a view to the setting up of knowledge-based extraction procedures. Likewise, the strategies followed to improve the compatibility of SUPRAS extracts with liquid and gas chromatography and adapt SUPRAS-based extractions to different formats are presented. Ongoing efforts to apply SUPRAS in multicomponent extractions and synthesize tailored SUPRAS for the development of innovative sample treatments are highlighted. Among challenges identified, discussion is focused on the automation of SUPRAS-based sample treatment and the elucidation of SUPRAS nanostructures, which are considered essential for their acceptance in routine labs and the design of tailored SUPRAS with programmed functions. Graphical abstract.

Determination of vitamin B12 in four edible insect species by immunoaffinity and ultra-high performance liquid chromatography

Insects are rich in major nutrients, such as protein and fat. Recently, minor nutrients like vitamins have become the subjects of interest in insects. Hence, this study reports on the development and validation of a method for the determination of vitamin B12 in mealworm (Tenebrio molitor larvae), cricket (Gryllus assimilis), grasshopper (Locusta migratoria) and cockroach (Shelfordella lateralis), using an ultra-high performance liquid chromatography approach with preliminary immunoaffinity chromatography sample preparation. The method was validated regarding linearity, specificity, accuracy and precision, as well as limits of detection/quantification, and was found to be satisfactory for the desired application. Found levels of vitamin B12 were 1.08 µg/100 g for mealworm, 2.88 µg/100 g for cricket, 0.84 µg/100 g for grasshopper, and 13.2 µg/100 g dry weight for cockroach, representing the first validated report on the content of vitamin B12 in edible insects. Observed interferences are likely caused by the presence of pseudovitamin B12.

Acetonitrile as tops solvent for liquid chromatography and extraction

This article deals with acetonitrile physico-chemical properties and its mixtures with water. It covers the information about isotherms of such parameters of the acetonitrile-water binary system as density, viscosity, permeation coefficient, refraction index, optic density, a boiling point isobar. Authors suggest a generalized criterion of acetonitrile polarity. The article also discusses means of polarity assessment and eluotropic strength of mobile phases on the basis of acetonitrile mixtures with water with application of generalized criteria. Special attention is paid to the options of acetonitrile application in various extraction methods of chromatographic sample preparation. The article also reveals advantages and problems of acetonitrile application as a mobile phase modifying agent in the HPLC reversed-phase and as a hydrophilic extra-agent in liquid-liquid extraction.

Serban Moldoveanu and Victor David: Modern sample preparation for chromatography

Serban Moldoveanu and Victor David: Modern sample preparation for chromatography

Fast derivatization of fatty acids in different meat samples for gas chromatography analysis

In order to analyze the composition of fatty acids employing gas chromatography as the separation method, a derivatization of lipids using esterification and transesterification reactions is needed. The methodologies currently available are time consuming and use large amounts of sample and reagents. Thus, this work proposes a new procedure to carry out the derivatization of fatty acids without the need for prior extraction of lipids. The use of small amounts of sample (100mg) allows the analysis to be performed in specific parts of animals, in most cases without having them slaughtered. Another benefit is the use of small amounts of reagents (only 2mL of NaOH/Methanol and H2SO4/Methanol). The use of an experimental design procedure (Design Expert software) allows the optimization of the alkaline and acid reaction times. The procedure was validated for five minutes in both steps. The method was validated for bovine fat, beef, chicken, pork, fish and shrimp meats. The results for the merit figures of accuracy (from 101.07% to 109.18%), precision (RSDintra-day (from 0.65 to 3.93%), RSDinter-day (from 1.57 to 5.22%)), linearity (R2=0.9864) and robustness confirmed that the new method is satisfactory within the linear range of 2–30% of lipids in the sample. Besides the benefits of minimizing the amount of samples and reagents, the procedure enables gas chromatography sample preparation in a very short time compared with traditional procedures.

Analytical challenges and solutions in doping control: a perspective from the Swedish Doping Control Laboratory.

BioanalysisVol. 8, No. 8 CommentaryAnalytical challenges and solutions in doping control: a perspective from the Swedish Doping Control LaboratoryMagnus EricssonMagnus Ericsson*Author for correspondence: E-mail Address: dopinglab@karolinska.se Doping Control Laboratory, Clinical Pharmacology, Karolinska University Hospital, Stockholm, SE 141 86, SwedenSearch for more papers by this authorPublished Online:23 Mar 2016https://doi.org/10.4155/bio-2016-0037AboutSectionsView ArticleView Full TextPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareShare onFacebookTwitterLinkedInReddit View articleKeywords: GC–MS/MSLC-HRMSOlympic GamesReferences1 World Anti-Doping Agency. The Prohibited List 2016. www.wada-ama.org.Google Scholar2 World Anti-Doping Agency. International Standard for Laboratories (ISL). www.wada-ama.org.Google Scholar3 Badoud F, Grataa E, Perrenoud L et al. Fast analysis of doping agents in urine by ultra-high-pressure liquid chromatography–quadrupole time-of-flight mass spectrometry I. Screening analysis. J. Chromatogr. A 1216, 4423–4433 (2009).Crossref, Medline, CAS, Google Scholar4 Girón A J, Deventer K, Roels K, Van Eenoo P. Development and validation of an open screening method for diuretics, stimulants and selected compounds in human urine by UHPLC–HRMS for doping control. Anal. Chim. Acta 721, 137–146 (2012).Crossref, Medline, Google Scholar5 World Anti-Doping Agency. The Technical document TD2016EAAS. www.wada-ama.org.Google Scholar6 Thörngren JO, Östervall F, Garle M. A high-throughput multicomponent screening method for diuretics, masking agents, central nervous system (CNS) stimulants and opiates in human urine by UPLC–MS/MS. J. Mass Spectrom. 43, 980–992 (2008).Crossref, Medline, Google Scholar7 World Anti-Doping Agency. The Technical document TD2015MRPL. www.wada-ama.org.Google Scholar8 Sottas PE, Saugy M, Saudan C. Endogenous steroid profiling in the athlete biological passport. Endocrinol. Metab. Clin. North Am. 39, 59 (2011).Crossref, Google Scholar9 Boscha J, Such-Sanmartína G, Seguraa J, Gutiérrez-Gallego B R. Tracking growth hormone abuse in sport: performance of marker proteins in a controlled setting. Anal. Chim. Acta 745, 118–123 (2012).Crossref, Medline, Google Scholar10 Van Renterghem P, Van Eenoo P, Sottas PE, Saugy M, Delbeke F. A pilot study on subject-based comprehensive steroid profiling: novel biomarkers to detect testosterone misuse in sports. Clin. Endocrinol. (Oxf.) 75(1), 134–140 (2011).Crossref, Medline, CAS, Google Scholar11 Schänzer W, Guddat S, Thomas A, Opfermann G, Geyer H, Thevis M. Expanding analytical possibilities concerning the detection of stanozolol misuse by means of high resolution/high accuracy mass spectrometric detection of stanozolol glucuronides in human sports drug testing. Drug Test. Anal. 5, 11–12 (2013).Crossref, Google Scholar12 Sobolevsky T, Rodchenkov G. Detection and mass spectrometric characterization of novel long-term dehydrochloromethyltestosterone metabolites in human urine. J. Steroid Biochem. Mol. Biol. 128(3–5), 121–127 (2012).Crossref, Medline, CAS, Google Scholar13 Buisson C, Marchand A, Bailloux I, Lahaussois A, Martin L, Molina A. Detection by LC–MS/MS of HIF stabilizer FG-4592 used as a new doping agent: Investigation on a positive case. J. Pharm. Biomed. Anal. 121, 181–187 (2016).Crossref, Medline, CAS, Google Scholar14 Leuenberger N, Barras L, Nicoli R et al. Hepcidin as a new biomarker for detecting autologous blood transfusion. Am. J. Hematol. doi: 10.1002/ajh.24313 (2016) (Epub ahead of print).Crossref, Medline, Google Scholar15 Malm C, Frangsmyr L, Holmberg S. Detection of autologous blood transfusion by proteomics: screening to find unique biomarkers. www.wada-ama.org/en/resources/science-medicine/detection-of-autologous-blood-transfusion-by-proteomicsscreening-to-find.Google ScholarFiguresReferencesRelatedDetailsCited ByCubosomic Supramolecular Solvents: Synthesis, Characterization, and Potential for High-Throughput Multiclass Testing of Banned Substances in Urine22 February 2022 | Analytical Chemistry, Vol. 94, No. 9Interest of HRMS systems in analytical toxicology: Focus on doping productsToxicologie Analytique et Clinique, Vol. 8A comprehensive study on the performance of different retention mechanisms in sport drug testing by liquid chromatography tandem mass spectrometryJournal of Chromatography B, Vol. 1178Supramolecular solvents in microextraction techniquesTwenty years of supramolecular solvents in sample preparation for chromatography: achievements and challenges ahead23 March 2020 | Analytical and Bioanalytical Chemistry, Vol. 412, No. 24Development and validation of a UHPLC-HRMS method for the simultaneous determination of the endogenous anabolic androgenic steroids in human serumJournal of Chromatography A, Vol. 1613Comprehensive analysis by liquid chromatography Q-Orbitrap mass spectrometry: Fast screening of peptides and organic molecules18 April 2018 | Journal of Mass Spectrometry, Vol. 53, No. 6 Vol. 8, No. 8 Follow us on social media for the latest updates Metrics Downloaded 162 times History Published online 23 March 2016 Published in print April 2016 Information© Future Science LtdKeywordsGC–MS/MSLC-HRMSOlympic GamesFinancial & competing interests disclosureThe author has no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.No writing assistance was utilized in the production of this manuscript.PDF download

Rapid QuEChERS Approach Using Novel Solid Phase Extraction for Insecticides in Lobster and Shellfish Tissue with Gas Chromatography–Tandem Mass Spectrometry

Novel, rapid, inexpensive, and simple QuEChERS extraction followed by phospholipid solid phase extraction was successfully developed and validated for the determination of methoprene, resmethrin, bifenthrin, cyhalothrin, and permethrin in lobster and shellfish tissues by gas chromatography–tandem mass spectrometry. This method is equivalent in final sample purity to the traditional gel permeation and open column chromatography sample preparation techniques, but has clear advantages due to reductions in time, labor, solvent use, and can be performed with minimal staff training. The proposed methodology was effectively applied to the analysis of North Atlantic lobster (hepatopancreas and muscle) and shellfish tissue. The linearity of the calibration curves for all analytes were R2 > 0.9991. The surrogate recoveries were 98.2 ± 18.0%, while the target compound recoveries, for fortified samples, were in the range of 62.0%–128.8% with RSD values <17.2% for all compounds. The detection limits for the analytes ranged from 0.0056 µg/g to 0.76 µg/g with 84.4–119.5% accuracy and relative standard deviations less than 3.77%.

Colorful quality control of chromatographic sample preparation

Multidimensional chromatographic separation for proteomic biomarker search generates sets of several hundred homologous fractions, which have to be compared. Due to the high number of sequential steps, deviations between samples may be produced randomly by slight processing differences. These deviations may falsify proteomic results. In order to overcome this problem, we tested the applicability of quality control by colored phycobilins as internal standards. The elution of the used protein standards themselves shows a high reproducibility since their main peak location is practically constant under proper performance of size exclusion and anion exchange chromatography. This applies to runs of one phycobilin alone, combined with another phycobilin, or combined with plasma proteins. Thus, these protein standards do not disturb sample processing. Characteristic peak shifts of phycobilins allow easy observation of deviations caused by typical failures in the elution protocol (aberrant step number, buffer permutation). Mass spectrometric analysis is not influenced by their presence since protein coverage, peptide numbers, and protein numbers are not altered. Thus, colored protein standards may be used for quality control and evaluation of robustness of various chromatographic applications.

Native chromatographic sample preparation of serum, plasma and cerebrospinal fluid does not comprise a risk for proteolytic biomarker loss

We recently developed a native multidimensional chromatographic method for serum and plasma fractionation for proteomic biomarker search. This method has several advantages:parallelization and automation, high reproducibility and proteome coverage, flexible dynamic range with respect to molecular weight and sample amount, optional enzymatic and immunological analytics additional to mass spectrometry, retaining metabolites, and information on complex formation, modification, and fragmentation of constituents. Nevertheless, native conditions have the probable risk of proteome alteration and biomarker loss by intrinsic proteinases. Hence, we tried to quantify here intrinsic proteolytic activity in native samples and fractions from serum, plasma and cerebrospinal fluid, as well as the effectiveness of intrinsic anti-proteinases during sample handling and preparation under our fractionation conditions. Therefore, we used several quantitative measures: (1) total proportion of intrinsic protein and peptide fractions, (2) azocasein hydrolysis and (3) mass spectrometric protein coverage and peptide numbers. To 1: In all non-fractionated specimens, neither decrease of protein concentration or molecular weight nor increase of peptide concentration was found after variable clotting or pre-incubation time. To 2: No azocasein hydrolysis was seen in these samples when prepared within a few hours at room temperature. Trypsin, when added in concentrations not higher than 0.85 μg/mL (0.04 μM), even was completely inhibited. Moreover, in native 1-D fractions no proteinase activity could be observed. To 3: Mass spectrometry confirmed that neither protein coverage nor peptide numbers differ significantly in 1-D or 2-D fractions after variable incubation time. These results suggest that intrinsic, native proteinase inhibitors potentially protect the proteomes considered, enabling “top-down” proteomic approaches under native conditions with serum, plasma and cerebrospinal fluid.

New sample preparation technologies

In recent years, increasing interest has been devoted to sample preparation for chromatography and capillary electrophoresis, including development of new techniques and strategies, and to theoretical description, for better understanding of the different processes. The former activities have provided the community with new technology, and the latter efforts have taught us how to operate the technologies and have converted sample preparation to a scientific discipline. Important driving forces for this research have been to improve selectivity and clean-up, to improve analyte enrichment, to reduce analysis time, to reduce the consumption of hazardous organic solvents, and to reduce the sample volumes required for analysis. In this special issue, different contributors to the development of sample preparation have been invited to present their recent work. Because space in this volume is limited, and because current research is a very broad field in terms of technologies and applications, the current collection is intended to give a flavor of the field rather than a comprehensive overview. Nevertheless, we hope the papers will be of high value, and that they can act as motivation for many other analytical chemists also to develop the field of sample preparation in the future. As we develop sample preparation further, we will be able to process more samples in a short time, to eliminate interferences, to detect compounds at lower concentration levels in complicated matrices, and to analyze new types of sample material; this will definitely give us much more scientific knowledge of chemical and biological systems in the future. We would like to thank all of the authors for their excellent contributions to this special issue on “New sample preparation technologies”. Anal Bioanal Chem (2009) 393:779 DOI 10.1007/s00216-008-2493-y

Electrical potential can drive liquid-liquid extraction for sample preparation in chromatography

In this review, we discuss three different approaches to liquid-liquid extraction (LLE) driven by an electrical field (dc): (1) electro extraction, by which ionic analytes are extracted from a stagnant organic solution (immiscible with water) into water; (2) electrochemically-modulated LLE (known as ITIES extraction, where ITIES means “interface between two immiscible electrolyte solutions”), by which ionic analytes are extracted from a flowing aqueous sample and into a stationary organo-gel; and, (3) electro-membrane extraction, by which ionic analytes are extracted from an agitated aqueous sample, through an organic solvent (supported liquid membrane) sustained in the pores in the wall of a porous hollow fiber, and into an aqueous acceptor inside the lumen of the hollow fiber. We review the literature with respect to these techniques, which we compare in terms of performance and working principles, and outline the promising aspects of using electrical fields to enhance and to manipulate LLE. In conclusion, we identify LLE driven by electrical fields as an important field for future development in sample preparation for chromatography and electrophoresis.

Preparation and characterization of new solid-phase microextraction fibers obtained by sol–gel technology and zirconium oxide electrodeposited on NiTi alloy

This study describes the use of zirconium oxide electrolytically deposited onto a NiTi alloy as a new substrate for sol–gel reactions. Polydimethylsiloxane (PDMS) was used to coat the fiber after activation of the NiTi–ZrO 2 surface with sodium hydroxide solution followed by hydrochloric acid solution. Micrographs obtained by scanning electron microscopy (SEM) showed good uniformity of the PDMS coating on the proposed substrate and also permitted the evaluation of coating thickness, being approximately 25 μm. Thermal stability of the coating on the NiTi–ZrO 2 surface was evaluated, showing excellent stability up to 320 °C. The applicability of the proposed NiTi–ZrO 2–PDMS fiber was evaluated through extraction of benzene, toluene, ethylbenzene and o-xylene (BTEX) from the headspace of aqueous samples. Some parameters affecting the extraction efficiency such as the salting-out effect, extraction temperature and extraction time were optimized by two consecutive two-level full-factorial experimental designs. This optimization allowed the experimental domain of maximum response to be attained and also the robustness range for the variables. Excellent detection limits in the range of 0.6–1.6 μg L −1 were obtained as well as correlation coefficients higher than 0.99994. Precision for one fiber ( n = 7) was in the range of 1.4–4.0% and fiber-to-fiber reproducibility ( n = 5) was in the range of 3.9–6.7%. Comparison of the extraction profile of the proposed fiber with those of commercially available 100, 30 and 7 μm PDMS fibers showed that NiTi–ZrO 2–PDMS had a better response compared to that of the 7 and 30 μm fibers. Such characteristics of the NiTi–ZrO 2–PDMS fiber suggest that this fiber represents an excellent alternative for gas chromatography sample preparation.

Interaction of Zonula Occludens-1 (ZO-1) with α-Actinin-4: Application of Functional Proteomics for Identification of PDZ Domain-Associated Proteins

The use of recombinant "bait" proteins to capture protein-binding partners, followed by identification of protein interaction networks by mass spectrometry (MS), has gained popularity and widespread acceptance. We have developed an approach using recombinant PDZ protein interaction modules of the membrane-associated guanylate kinase (MAGUK) protein zonula occludens-1 (ZO-1) to pull-down and screen for proteins that interact with these modules via their PDZ domain binding motifs. Identification of proteins by MS of pull-down material was achieved using a vacuum-based chromatography sample preparation device designed for matrix-assisted laser desorption/ionization (MALDI) MS. MS analysis of tryptic fragments in pull-down material revealed a number of potential ZO-1 interacting candidates, including the presence of peptides corresponding to the cortical membrane scaffolding protein alpha-actinin-4. Interaction of alpha-actinin-4 with ZO-1 was confirmed by coimmunoprecipitation of these two proteins from cultured cells, as well as from brain, liver, and heart, and by immunoblot detection of alpha-actinin-4 after pull-down with the first PDZ domain of ZO-1. In contrast, the highly homologous alpha-actinin family member, alpha-actinin-1, displayed no association with ZO-1. Immunofluorescence showed colocalization of alpha-actinin-4 with ZO-1 in cultured HeLa and C6 glioma cells, as well as in a variety of tissues in vivo, including brain, heart, liver, and lung. This study demonstrates the utility of MS-based functional proteomics for identifying cellular components of the ZO-1 scaffolding network. Our finding of the interaction of ZO-1 with alpha-actinin-4 provides a mechanism for linking the known protein recruitment and signaling activities of ZO-1 with alpha-actinin-4-associated plasma membrane proteins that have regulatory activities at cell-cell and cell-extracellular matrix contacts.

Solutions and challenges in sample preparation for chromatography.

Sample preparation as practiced today in analytical laboratories is a complex combination of classical and modern techniques. In this review, the progress made in the last few years in sample preparation for chromatography is examined and discussed in comparison with previous achievements in the field. Discovery and development of new materials is seen as one of the main sources of progress, but finding better ways of using the old principles and the improvements in technology are also major contributing factors for advancement. Practical demands for analysis of pharmaceutical products, the environmental studies, and life science are the main driving forces for development in sample preparation for chromatography.

Restricted access chromatographic sample preparation of low mass proteins expressed in human fibroblast cells for proteomics analysis

Two-dimensional electrophoresis and modern image analysis systems have made it possible to study protein expression and regulation of proteins in biological systems. Proteins in the molecular mass region of 20–120 kDa are well investigated and described. However, proteins with masses below 20 kDa are the least investigated as they are rarely seen on 2D-PAGE due to fast migrations in the electric field and lack of staining efficiency. This paper describes a technique that enriches proteins in the lower mass region using solid-phase extraction. The purification step is carried out using C 18 functionalised “restricted access” affinity chromatography whereby simultaneous trace enrichment and sample clean up is achieved. In this study expression patterns of TGF-β stimulated and non-stimulated fibroblasts were compared after the solid-phase fractionation procedure. An increased expression pattern was obtained whereby 400 protein spots could be detected by image analysis in the <20-kDa region. Out of these, specific regulations of 14 spots were found by quantitative image analysis and spots of interest were identified with MALDI TOF–MS. The regulated and identified proteins were triosephosphate isomerase, cofilin and heat shock 27-kDa protein.

Use of laboratory robotics for gel permeation chromatography sample preparation: Automation of high‐temperature polymer dissolution

Manual preparation of polymer samples for molecular weight characterization by solution methods such as gel permeation chromatography (GPC) is a time-consuming, labor-intensive, and redundant task. Preparation of samples for high-temperature GPC characterization further complicates the procedure. A typical manual high-temperature sample preparation exposes the analyst to both hot surfaces and solvent vapors. An automated system to prepare samples for high temperature GPC analysis has been developed. The system is based on a Zymark laboratory robotic system, and custom hardware peripherals developed at The Dow Chemical Company. The automated procedure performs all the steps required to prepare samples for high-temperature GPC analysis, including the hot steps. The samples were analyzed using the Waters 150-C GPC in combination with the differential refractive index (DRI) and low-angle laser light scattering (LALLS) detectors to demonstrate the reproducibility and reliability of the automated procedure. The system hardware, software options, and performance are presented in this paper. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 64: 1613–1623, 1997

Use of laboratory robotics for gel permeation chromatography sample preparation: Automation of high-temperature polymer dissolution

Manual preparation of polymer samples for molecular weight characterization by solution methods such as gel permeation chromatography (GPC) is a time-consuming, labor-intensive, and redundant task. Preparation of samples for high-temperature GPC characterization further complicates the procedure. A typical manual high-temperature sample preparation exposes the analyst to both hot surfaces and solvent vapors. An automated system to prepare samples for high temperature GPC analysis has been developed. The system is based on a Zymark laboratory robotic system, and custom hardware peripherals developed at The Dow Chemical Company. The automated procedure performs all the steps required to prepare samples for high-temperature GPC analysis, including the hot steps. The samples were analyzed using the Waters 150-C GPC in combination with the differential refractive index (DRI) and low-angle laser light scattering (LALLS) detectors to demonstrate the reproducibility and reliability of the automated procedure. The system hardware, software options, and performance are presented in this paper. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 64: 1613–1623, 1997

Microdetermination of 2,3-dinor-6-ketoprostaglandin F1 alpha in human urine using gas chromatography-high-resolution selected-ion monitoring.

The microdetermination of 2,3-dinor-6-ketoprostaglandin F1 alpha (I) in human urine is described. Samples to which the [2H4]-analogue was added as an internal standard were extracted by chromatographic sample preparation using a Bond Elut C18 cartridge and a silica gel column. Conversion of the extracted I into the 1-methyl ester-6-methoxime-9,11,15-trisdimethylisopropylsilyl ether derivative was followed by gas chromatography-high-resolution selected-ion monitoring (GC-HR-SIM). Interfering substances from the urine matrix were eliminated during GC-HR-SIM analysis using a DB-1 column. A good linear response over the range 10 pg-100 ng per tube was demonstrated. Compound I could be detected in the range 26-375 pg/ml of human urine. The proposed method can be applied to the determination of I in human urine.