Capillary Sampling Technique Research Articles

Clinical Validation of a Capillary Blood Home-Based Self-Sampling Technique for Monitoring of Infliximab, Vedolizumab, and C-Reactive Protein Concentrations in Patients With Inflammatory Bowel Disease.

Therapeutic drug monitoring provides important guidance for treatment of patients with inflammatory bowel disease (IBD) and could help to early identify treatment failure. This study aimed to validate a finger prick-based capillary blood sampling technique to measure biological trough levels and C-reactive protein (CRP) and evaluate patient performance and -support. In this prospective cohort study, patients with IBD receiving infliximab (IFX) or vedolizumab (VEDO) therapy performed finger prick-based capillary blood sampling at home. Additionally, blood was collected through routinely performed in-hospital venepuncture prior to biological infusion. IFX, VEDO, and CRP concentrations were measured by enzyme-linked immunosorbent assay. The concordance between methods was statistically evaluated and a survey was conducted to assess practicality and patient support. In total, 81 patients (46 IFX, 35 VEDO) were enrolled. Mean differences between both methods were 0.42 (95% confidence interval, -1.74 to 2.58) μg/mL for IFX and 0.72 (95% confidence interval, -5.50 to 6.94) μg/mL for VEDO. Passing-Bablok regressions demonstrated no evidence for systematic or proportional biases. Venous and capillary IFX (ρ = 0.96, P < .001) and VEDO (ρ = 0.97, P < .001) levels strongly correlated and showed high intermethod agreement (Cohen's kappa: IFX = 0.82; VEDO = 0.94). Similarly, venous and capillary CRP levels were strongly correlated (ρ = 0.99, P < .001). Most patients (>95%) were able to successfully perform the self-sampling at home without prior instructions. This study clinically validated a finger prick-based capillary blood self-sampling technique allowing concomitant home monitoring of biological levels and CRP for patients with IBD, who reported substantial support, tolerability, and practicality.

Activated alumina market size & share 2021: North America, Europe, & APAC industry forecasts 2027

Catalytic partial oxidation (CPO) reactors have complex concentration and temperature gradients which make it difficult to understand the mechanism of autothermal operation. Previous research in the Schmidt group on methane CPO using the capillary sampling technique has shown the existence of two zones – oxidation and reforming [1], [2], [3], [4]. Nearly (>90%) all of the oxygen in the feed is converted within the first 2 mm of the catalyst bed. In this paper, temperature and concentration profiles during the CPO of methane and dimethyl ether CH3OCH3, an oxygenated hydrocarbon, are presented. Results with the two feeds are compared and the nature of the profiles was similar, with sharp gradients existing in the oxidation zone with slower chemistries in the reforming section. The rhodium catalyst in the oxidation zone during methane CPO was also analyzed using XPS and XRD and shown to be rhodium metal.

Fine Needle Aspiration versus Fine Needle Capillary Sampling Technique in Cyto-diagnosis of Thyroid Lesions

Introduction: In diagnosis of thyroid lesions, the negative pressure applied during fine needle aspirationcytology (FNAC) frequently produces bloody smears. This results in a compromise in cellular concentrationand architecture which may lead to improper interpretation. Fine needle capillary sampling cytology(FNCC), on the other hand, avoids active aspiration as it depends on capillary tension to collect tissuesamples in the needle bore. This study evaluated the diagnostic performance of FNAC and FNCC in thyroidlesions. Methods: A total of 120 patients were included in this study conducted over a duration of 19months. All thyroid swellings advised for cyto-diagnosis were sampled by both fine-needle aspiration(FNAC) and non-aspiration (FNCC) techniques. The slides were assessed according to the Mair et al.scoring system. Results: In the FNCC group, 72 (60%) smears were diagnostically superior while 54 (45%)smears were diagnostically superior in the FNAC group. Blood contamination (p=0.003), cellular trauma(p=0.019), and degree of cellular degeneration (p=0.026) were less and cellular architecture (p=0.047) waspreserved more in FNCC in comparison to FNAC groups. Conclusion: This study showed the superiority ofFNCC for the interpretation and diagnosis of thyroid lesions. However, the combination of both FNAC andFNCC could maximize the diagnostic yield.

Catalytic Methane Combustion on a Pt Gauze: Laser‐Induced Fluorescence Spectroscopy, Species Profiles, and Simulations

AbstractProfile measurements in a catalytic gauze reactor are conducted for catalytically assisted methane combustion over platinum. The reactor combines a capillary sampling technique with a novel fiber‐optic laser‐induced fluorescence spectroscopy method for the detection and quantification of gas phase OH• radicals serving as indicator species for gas phase reactions. Experimental profiles are compared with three‐dimensional numerical reactor simulations including flow, mass transport, heat transport, and microkinetic models for both surface and gas phase chemistry. The results provide insights into the interaction of chemistry and transport upstream of, at, and downstream of the catalytic gauze, and the interaction of surface and gas phase reactions by exchange of heat and radicals released from the catalyst surface.

Methane Oxidation over Palladium: On the Mechanism in Fuel-Rich Mixtures at High Temperatures

A kinetic modeling study on methane oxidation over reduced Pd for various fuel-rich conditions around the stoichiometric point of the partial oxidation at high temperatures (900–1100 K) is presented. A thermodynamically consistent detailed surface reaction mechanism is developed within the mean field approximation. The proposed kinetic model consists of 54 elementary-step based reactions including seven gas-phase species and 15 surface intermediates. Three different methane activation paths are implemented, comprising pyrolytic C–H bond dissociation steps, oxygen-assisted and dual-oxygen-assisted CH4 activation. In situ experimental measurements in a quasi-autothermally operated flow reactor, using the capillary sampling technique, are performed for model evaluation. The provided experimental data includes spatially resolved temperature and concentration profiles within a single catalytic channel of a Pd/Al2O3-coated monolith. Supplementary numerical simulations based on literature data for fuel-lean and fuel-rich conditions at high temperatures extend the model’s capability to predict a wide range of different experimental conditions.

Numerical simulation of a structured catalytic methane reformer by DUO: The new computational interface for OpenFOAM® and DETCHEM™

The catalytic partial oxidation of methane over a honeycomb-structured Rh/Al2O3 coated catalyst is studied at a molar C/O ratio of unity and short-contact times experimentally and numerically. Axial species and temperature profiles inside the catalytic monolith are measured by a capillary sampling technique. A detailed numerical analysis of the flow, temperature and species concentration profiles is conducted using the new software tool DUO, which is an interface for the coupling of the computational tools OpenFOAM® and DETCHEM™. This interface enables the integration of detailed surface chemistry into OpenFOAM® and allows the time-efficient calculation of structured catalysts and other catalytic reactors with multiple combined fluid and solid regions including heterogeneous reactions. In comparison with experimental data, spatial profiles of species and temperature are analyzed. The thermal boundary conditions are shown to have a strong impact on reliable predictions. Even though the characteristics of the influence of radial heat loss on the conversion can be governed, the use of a radiation model is recommended.

Spatial profiles in partial oxidation of methane and dimethyl ether in an autothermal reactor over rhodium catalysts

Catalytic partial oxidation (CPO) reactors have complex concentration and temperature gradients which make it difficult to understand the mechanism of autothermal operation. Previous research in the Schmidt group on methane CPO using the capillary sampling technique has shown the existence of two zones – oxidation and reforming [1–4]. Nearly (>90%) all of the oxygen in the feed is converted within the first 2mm of the catalyst bed. In this paper, temperature and concentration profiles during the CPO of methane and dimethyl ether CH3OCH3, an oxygenated hydrocarbon, are presented. Results with the two feeds are compared and the nature of the profiles was similar, with sharp gradients existing in the oxidation zone with slower chemistries in the reforming section. The rhodium catalyst in the oxidation zone during methane CPO was also analyzed using XPS and XRD and shown to be rhodium metal.

Mo1412 The 25G FNA Needle: Good for Onsite but Poor for Offsite Evaluation? Results of a Randomized Trial

Mo1412 The 25G FNA Needle: Good for Onsite but Poor for Offsite Evaluation? Results of a Randomized Trial

Fuel-rich methane oxidation in a high-pressure flow reactor studied by optical-fiber laser-induced fluorescence, multi-species sampling profile measurements and detailed kinetic simulations

A versatile flow-reactor design is presented that permits multi-species profile measurements under industrially relevant temperatures and pressures. The reactor combines a capillary sampling technique with a novel fiber-optic Laser-Induced Fluorescence (LIF) method. The gas sampling provides quantitative analysis of stable species by means of gas chromatography (i.e. CH4, O2,CO,CO2, H2O,H2, C2H6, C2H4), and the fiber-optic probe enables in situ detection of transient LIF-active species, demonstrated here for CH2O. A thorough analysis of the LIF correction terms for the temperature-dependent Boltzmann fraction and collisional quenching are presented. The laminar flow reactor is modeled by solving the two-dimensional Navier–Stokes equations in conjunction with a detailed kinetic mechanism. Experimental and simulated profiles are compared. The experimental profiles provide much needed data for the continued validation of the kinetic mechanism with respect to C1 and C2 chemistry; additionally, the results provide mechanistic insight into the reaction network of fuel-rich gas-phase methane oxidation, thus allowing optimization of the industrial process.

Feasibility and acceptability of rapid HIV test screening (DEPIVIH) by French family physicians

BackgroundIn France, around 50,000 people were unaware of their HIV positivity at the end of 2008. The latest guidelines recommend routine screening of all adults. Family physicians have been identified as key persons for this new policy. Rapid HIV tests (RHT) have been proposed as an alternative to conventional blood tests. ObjectivesThe authors assessed the feasibility and acceptability of RHT test based screening in French community practice. MethodWe made a prospective interventional study of the BioMerieux VIKIA® HIV 1/2 RHT among French family physicians. Data on the RHT was posted in the physician's waiting room. ResultsSixty-two French physicians, mostly family practitioners, included 383 patients with a mean age of 36.2 years, from June to October 2010. Twenty-two percent (83) of these patients had never been tested for HIV. The RHT was proposed and 382 tests were accepted and performed (acceptability rate of 99.7%). Sixty-five percent of the tests were made on the patient's request. The tested population represented 1.5% of consulting patients during the study period (feasibility rate). Patients were quite satisfied but physicians less so. Test steps and capillary blood sampling were the main source of difficulty mentioned. At the end of the study, 59% of physicians were ready to continue using RHT in their daily practice. ConclusionRoutine RHT screening in community practice is feasible and well accepted by patients. It was the first screening test for 22% of our patients. Its feasibility was limited by capillary blood sampling technique and time constraints during consultation.

Mo1396 Endoscopic Ultrasound-Guided Fine Needle Aspiration Versus Fine-Needle Capillary Sampling Biopsy of Pancreatic Solid Lesions: Does Technique Matter?

Mo1396 Endoscopic Ultrasound-Guided Fine Needle Aspiration Versus Fine-Needle Capillary Sampling Biopsy of Pancreatic Solid Lesions: Does Technique Matter? Ann M. Chen, Walter G. Park, Shai Friedland, Subhas Banerjee Gastroenterology, Stanford University School of Medicine, Palo Alto, CA Background: Endoscopic ultrasound guided fine needle aspiration (EUS-FNA) is a sensitive and safe procedure for evaluation of solid lesions of the pancreas. However, an accurate diagnosis is highly dependent on the quality of the specimen obtained. Although the procedure is increasingly performed, aspiration technique varies greatly among endosonographers with no studies comparing the results. Aspiration with a syringe suction is one of the more common techniques used currently. A more novel biopsy method employed by radiologists in percutaneous FNA of the thyroid utilizes only capillary aspiration created by slow withdrawal of the stylet. It is not know if this technique may also provide higher yield in EUS-FNA of solid pancreas lesions. Methods: A retrospective study of patients at our institution undergoing EUS-FNA of solid pancreatic masses from August 2008 to November 2010 was performed. Final cytology report was compared with subsequent surgical histopathology or longterm clinical follow-up. Results: A total of 91 patients with solid pancreatic masses underwent EUS-FNA using either the stylet capillary sampling (CS) technique (n 45) or a 5ml syringe suction (SS) method(n 46) were identified. The sensitivity, specificity, PPV, and NPV were 94%, 100%, 100%, and 88%, respectively for CS compared to 80%, 100%, 100%, and 71%, respectively for SS. While there was a trend toward more superior diagnostic performance with CS, a statistical significance was not reached in this small study (P 0.13). Of the 6 patients who had non-diagnostic SS aspirates, final diagnosis of adenocarcinoma (n 5) or neuroendocrine tumor (n 1) was found by percutaneous biopsy (n 2), surgery (n 2), or bile duct brushings. Of the 2 patients in the CS group with initial non-diagnostic biopsies, one underwent repeat biopsy with the CS technique which revealed adenocarcinoma. The other patient with severe pancreatitis had atypical cytology. Subsequent surgery confirmed suspicion of adenocarcinoma. The mean number of needle passes required for diagnosis was the same (n 3.4) for both techniques but the quality of the cytology specimen graded by blinded pathologists was abundantly cellular in 55% of CS specimens compared to only 33% of the SS samples. This difference was observed despite smaller mean size of pancreatic lesions sampled by CS (mean 2.2cm, 95% CI 1.72.7) compared to those sampled by SS (mean 3.2cm, 95% CI 2.8-3.7). Limitations: Single-center retrospective study Conclusions: Fine needle capillary sampling technique appears to be more sensitive and has a higher NPV than suction aspiration of solid pancreas lesions. Higher quality of cytology smear is observed with the capillary methoid which may be a result of reduced tissue trauma and less bloody aspirate. Further prospective randomized studies of this promising technique are warranted.

Catalytic partial oxidation of ethane to ethylene and syngas over Rh and Pt coated monoliths: Spatial profiles of temperature and composition

The catalytic partial oxidation of C 2H 6 over Pt and Rh coated monolithic supports (4.7 wt% M/α-Al 2O 3 45 PPI) was investigated with a capillary sampling technique for a range of C 2H 6/air ratios at constant inlet flow (∼8 ms contact time), with and without H 2 addition. Effluent data clearly indicate the differences in product distribution between catalysts and equilibrium. Rh effectively converts the reactant mixtures to syngas with ∼80% selectivity, whereas Pt produces C 2H 4 with ∼55% C-atom selectivity, while neither produces thermodynamically favored C. Spatially resolved measurements provide direct evidence of the multi-zone nature of the reactors. With Rh, complete conversion of O 2 occurs to produce mostly CO, H 2 and H 2O within the first 3 mm of catalyst, followed by a reforming zone to produce additional syngas. Pt consumes O 2 more slowly, which results in a steady increase in temperature along the reactor. Ethylene formation correlates to reactor temperatures >750 °C, regardless of C/O, in line with the onset of homogeneous reactions. Hydrogen addition tests (C 2H 6/O 2/H 2=2/1/2) clearly exhibit preferential oxidation of H 2 with O 2 over Pt, which shifts the maximum in temperature upstream while preserving a portion of the C 2H 6 for C 2H 4 production. H 2 addition modifies the concentration and temperature profiles minimally on Rh. The main differences between catalysts are the high reforming and O 2 consumption activity with Rh compared to Pt, which are likely responsible for differences in C 2H 4 yields.

Effects of H 2O and CO 2 addition in catalytic partial oxidation of methane on Rh

The autothermal catalytic partial oxidation (CPO) of methane was performed at short contact times (∼8 ms) over three Rh-based catalysts: 5 wt% Rh/ α-Al 2O 3, 5 wt% Rh/2 wt% γ-Al 2O 3/ α-Al 2O 3, and 5 wt% Rh/2 wt% Ce/2 wt% γ-Al 2O 3/ α-Al 2O 3. The effects of H 2O addition (10%, 20%, and 40% of the total feed) and CO 2 addition (20% and 35%) were studied over a wide range of inlet C/O ratios (0.75–1.2) by means of the capillary sampling technique. Over Rh/ α-Al 2O 3 samples, spatially resolved concentration profiles revealed that the rate of CH 4 reforming is independent of the concentration of H 2O and CO 2. Differences in the product distribution followed the behavior expected from water gas shift (WGS) chemistry: in H 2O-rich tests, the production of H 2 and CO 2 increased at the expense of H 2O and CO, while the opposite was observed in CO 2-rich tests. CPO experiments with a simultaneous feed of H 2O and CO 2 (40% H 2O, 20% CO 2, 20% CH 4, C/O = 1) provided direct evidence that H 2O is the preferential co-reactant of CH 4 in reforming and that CO 2 reforming is absent. Addition of a γ-Al 2O 3 washcoat to the catalyst significantly enhanced the rate of steam reforming while revealing the limits of Rh WGS activity. Products were equilibrated for nearly all cases examined over the Ce-promoted catalyst, indicating that WGS kinetics, either forward or reverse, have an important role in the CPO mechanism, particularly with H 2O and CO 2 co-feed. The experimental results clearly illustrate the flexible nature of CPO process. They show that the H 2/CO can be varied within a wide range of values in a one-step process, and syngas production is sustainable under highly diluted conditions.

Methane catalytic partial oxidation on autothermal Rh and Pt foam catalysts: Oxidation and reforming zones, transport effects, and approach to thermodynamic equilibrium

We compare Rh and Pt as catalysts for the partial oxidation of methane to syngas at millisecond contact times. The basis for the comparison are species and temperature profiles, with a spatial resolution of about 300 μm measured along the centerline of an adiabatically operated metal-coated α-Al2O3 foam using a capillary sampling technique with mass spectrometric species measurement. Gas temperature profiles are measured with a thermocouple. Investigated stoichiometries range from C/O=0.6 to 2.6 at constant flow rate of 4.7 slpm and atmospheric pressure. Rh and Pt are compared with respect to (i) profile development at syngas stoichiometry, (ii) profile development at varying stoichiometries from C/O=0.6–2.6, (iii) product selectivities and yields in the oxidation zone, (iv) contribution of partial oxidation and steam reforming to the final syngas yield, (v) mass transport limitations, and (vi) approach to thermodynamic equilibrium. Independent of C/O and metal, all profiles show an oxidation zone and a steam-reforming zone. H2 and CO are formed in the presence of gas-phase oxygen by partial oxidation and in the absence of gas-phase oxygen by steam reforming. CO2 reforming is not observed. At the same C/O, H2 and CO selectivities and yields are higher in the oxidation zone on Rh than on Pt. As the C/O ratio increases, the catalyst temperature decreases and selectivities to H2 and CO in the oxidation zone decrease. The decrease is larger on Pt than on Rh. Because Rh is also the better steam-reforming catalyst, H2 and CO yields are generally higher on Rh than on Pt. The rate of O2 conversion at the catalyst entrance is largely mass transport-controlled on Rh but not on Pt. In the oxidation zone on Pt, the methane CPO is kinetically controlled with a constant reaction rate. An average O2 mass transport coefficient is calculated and compared with literature values on foam catalysts. Finally, exit species flow rates and temperatures are compared with thermodynamic calculations at constant pressure and enthalpy. Rh brings the methane oxidation close to equilibrium if C/O⩽1.0, whereas Pt reaches equilibrium only at very high catalyst temperatures if C/O⩽0.7. At higher C/O, deviations from equilibrium are observed mainly because steam-reforming slows, but also because water–gas shift equilibrium is not established.

Spatial and temporal profiles in millisecond partial oxidation processes

Methods are presented to measure axial species and temperature profiles within catalytic partial oxidation foam monoliths at atmospheric pressure with 0.3 mm spatial resolution using a capillary sampling technique with a quadrupole mass spectrometer. The system allows sampling within the catalyst with negligible interference in flow or temperature by using a 0.6 mm quartz capillary containing a thermocouple and possessing a 0.3 mm side orifice. The capillary tightly fills a concentric channel drilled within the 10 mm long ceramic foam minimizing gas bypass. This technique has been used to measure axial catalyst species profiles at temperatures up to 1300 °C for catalytic partial oxidation of methane and ethane to synthesis gas and ethylene, respectively. CH4 and O2 conversion are approximately twice as fast on Rh than on Pt. For C2H6 the reaction products at the catalyst entrance are H2, H2O, CO, and CO2. Ethylene production begins only after ~4 mm into the catalyst after most of the O2 has reacted. Transient operation where the feed composition is varied stepwise between different C/O ratios has also been used to characterize these systems. The capillary sampler has a time resolution of ~0.05 s, and C/O step changes within 0.5 s have been achieved using mass flow controllers. For switches from C/O = 0.6 to 1.4, sharp overshoots are observed for syngas (H2 and CO) and similar undershoots for combustion products (H2O and CO2). By placing the sampling orifice at different positions and stepping the C/O ratio, spatio-temporal profiles can be obtained. Spatio-temporal profiles are extremely important in validating detailed reaction mechanisms because their information content is much higher compared to integral steady state measurements at the reactor outlet. The spatial profiles show where and how quickly different species are formed or consumed along the catalyst axis. Transient profiles provide additional diagnostics of mechanisms and surface coverages because they show how temperature and species concentrations follow a perturbation from steady state.

Co-pyrolysis of Göynük-oil shale and Şırnak-asphaltite from Turkey and analysis of co-pyrolysis products by capillary GC total stream sampling technique ☆

Temperature-programmed co-pyrolysis of Göynük-oil shale (GOS) with Şırnak-asphaltite (ASP) from Turkey was investigated. The aim of this research was to determine the volatile product distribution and product evolution rate of co-processing of GOS with ASP. A series co-pyrolysis operation was performed with GOS and ASP using a 1/2, 1/1, 2/1 total carbon ratio of GOS to ASP. A fixed-bed reactor was used to pyrolyse small sample of GOS and ASP mixture under an inert gas flow (Argon). A special sampling technique was used for collecting organic products eluted from the reactor at different temperature and time intervals. The co-pyrolysis products were analyzed by capillary gas chromatography and the total product evolution rate was investigated as a function of temperature and time. n-Paraffins and 1-olefins in aliphatic fraction of pyrolysis products were classified as a carbon number. In addition, the recovery of total organic carbon as an organic volatile product was determined. The assessments were based on incorporating the results on temperature-programmed pyrolysis of GOS and ASP. The effect of co-processing of GOS with ASP was determined by calculating the difference between the experimental and the hypothetical mean value of conversion of total organic carbon into volatile products.

Subcutaneous tissue oxygen and carbon dioxide tensions during hyperbaric oxygenation: an experimental study in rats.

To investigate the response of subcutaneous tissue oxygen (O2) and carbon dioxide (CO2) tensions to hyperbaric oxygenation. Experimental study. University hospital, Finland. 10 Wistar rats. Subcutaneous tissue PO2 and PCO2 were directly measured with an implanted Silastic tube tonometer and capillary sampling technique while breathing air and exposed to hyperbaric oxygen (HBO) at 2.5 or 2.8 ATA pressure. Hyperbaric exposures were carried out in a large multiplace chamber pressurised with air. Subcutaneous tissue PO2 and PCO2. The mean subcutaneous PO2 rose from the baseline of 8 kPa (60 mmHg) to 16 kPa (112 mmHg) when rats breathed room air during pressurisation to 2.8 atm. When the rats breathed oxygen at 2.5 ATA the maximal mean tissue PO2 was four times higher than the mean starting value. During the HBO treatment at 2.8 ATA the tissue PO2 rose to a value about five times above baseline. The tissue PCO2 values almost doubled during the exposure to HBO at 2.5 ATA, probably because elimination of carbon dioxide was impaired. Measurements of tissue PO2 and PCO2 with an implanted Silastic tonometer and a capillary sampling technique can successfully be adapted to hyperbaric conditions. The method yielded reproducible results and is applicable to clinical use in hyperbaric medicine.

A Comparison of Venous Versus Capillary Measurements of Drug Concentration

Accessing patient's veins for drug level sampling is not always feasible. The use of capillary sampling techniques is often utilized when venous access is hampered. In the therapeutic monitoring of patients, unexpected drug level results often occur that can be caused by a number of different factors. The possibility that differences in assay results might occur if samples were collected by capillary stick vs. venous phlebotomy was examined by simultaneous sampling in 18 patients. Although correlation was very high (0.999) and percentage differences fairly low (range of 0 to 15.4%), a statistical difference was noted in the sampling methods. The precision was 6.5 +/- 6.58% and there was a slight negative bias (-3.76%), with capillary samples less than venous samples. Although there were statistical differences for the drugs studied in the concentration ranges evaluated, capillary samples should provide fairly small errors when compared to venous samples.

ChemInform Abstract: Recent Developments in Analytical Chromatography

Capillary gas chromatography (GC) is rapidly reaching a state of maturity. Recent advances in GC include new highly selective and stable open-tubular columns, capillary sampling techniques, and element-sensitive (plasma) detectors. An impressive growth of modern liquid chromatography continues with an emphasis on the separations of biopolymers, new silica-based and stable polymeric packings, microcolumn techniques, electroosmotically driven separations, and ultrasensitive detection. Supercritical fluid chromatography has gained considerable attention primarily because of its distinctive detection capabilities. Novel combinations of chromatographic techniques with each other, or with spectroscopic methods, continue to be explored.

Recent Developments in Analytical Chromatography

Capillary gas chromatography (GC) is rapidly reaching a state of maturity. Recent advances in GC include new highly selective and stable open-tubular columns, capillary sampling techniques, and element-sensitive (plasma) detectors. An impressive growth of modern liquid chromatography continues with an emphasis on the separations of biopolymers, new silica-based and stable polymeric packings, microcolumn techniques, electroosmotically driven separations, and ultrasensitive detection. Supercritical fluid chromatography has gained considerable attention primarily because of its distinctive detection capabilities. Novel combinations of chromatographic techniques with each other, or with spectroscopic methods, continue to be explored.