SAMPLE INJECTION IN PROGRAMMED TEMPERATURE GAS CHROMATOGRAPHY AND ITS SIGNIFICANCE FOR TRACE ANALYSIS

1965 ◽  
Vol 43 (5) ◽  
pp. 1560-1568 ◽  
Author(s):  
L. W. Hollingshead ◽  
H. W. Habgood ◽  
W. E. Harris
Keyword(s):  
Trace Analysis ◽  
Initial Temperature ◽  
Retention Volume ◽  
Total Sample ◽  
Sample Volume ◽  
Plate Height ◽  
Peak Broadening ◽  
Increased Sensitivity ◽  
Experimental Values ◽  
Total Sample Volume

The measurement of apparent plate heights resulting from various values of the total sample volume has been carried out for C5 to C8n-alkanes on Apiezon L under both isothermal and p.t.g.c. conditions. Plug injection of samples was achieved through the use of a syringe plunger driven at constant speed by a motor. The time for injection of gas samples ranged from 1 to 300 s. All of the results, both isothermal and p.t.g.c, could be correlated to the same plot of Happ/Hc against √nΔVs/VT0 where Happ is the observed plate height, Hc the limiting plate height at low sample volumes, n the true plate number, ΔVs the sample volume, and VT0 the isothermal retention volume at the initial temperature. The experimental values lie somewhat above the theoretical curve calculated by van Deemter et al. It is confirmed that sample volumes less than [Formula: see text] give negligible excess peak broadening. Applying these concepts to trace analysis, very large samples may be used in p.t.g.c. under such initial temperature conditions that the major component is only weakly retained, while traces of heavier components are concentrated into narrow bands and eluted as sharp peaks with the increased sensitivity provided by the large sample. As an example, chromatograms are presented for the p.t.g.c. analysis of natural gas on deactivated alumina, using sample volumes ranging from 2 to 500 ml.

On-line liquid-chromatographic analysis for drugs in serum with the Technicon "FAST-LC" system: performance data for theophylline and for four commonly used anticonvulsants and their metabolites.

1980 ◽  
Vol 26 (7) ◽  
pp. 871-880 ◽  
Author(s):  
J W Dolan ◽  
S van der Wal ◽  
S J Bannister ◽  
L R Snyder
Keyword(s):  
High Performance ◽  
Total Sample ◽  
Sample Volume ◽  
Active Metabolites ◽  
Serum Samples ◽  
New Instrument ◽  
On Line ◽  
Liquid Chromatographic Analysis ◽  
Liquid Chromatographic ◽  
Total Sample Volume

Abstract We describe a new instrument for use in assay of therpeutic drugs in serum by "high-performance" liquid chromatography, the "FAST-LC" system (Technicon). Serum samples are aspirated directly into the unit, extracted with solvent, and the evaporated and redissolved extract is injected onto a chromatographic column. We illustrate the performance of the system by assays in serum for theophylline and four anticonvulsants (primidone, phenobarbital, phenytoin, and carbamazepine) plus two of their active metabolites (phenylethylmalonamide and carbamazepine epoxide). For theophylline, final chromatograms are monitored at 270 nm, at analysis rates of 10/h. Concentration and absorbance are linearly related from 0 to 130 mg of theophylline per liter. For the anticonvulsants, chromatograms are monitored at 200 nm, at analysis rates of 7.5/h. The six individual determinations are each linear beyond the therapeutic range. For both drug panels, day-to-day CV's were 4 to 6%. Results correlate well with those by enzyme immunoassay. A total sample volume of 150 microL is required.

New techniques and tools for clinical chemistry.

1983 ◽  
Vol 29 (9) ◽  
pp. 1659-1664 ◽  
Author(s):  
G M Hieftje
Keyword(s):  
Ion Chromatography ◽  
Clinical Chemistry ◽  
Absorption Spectrometry ◽  
Total Sample ◽  
Sample Volume ◽  
Beam Optics ◽  
New Techniques ◽  
Double Beam ◽  
Total Sample Volume ◽  
Potential Use

Abstract In this paper are described and evaluated several new tools of potential use in clinical chemistry. The first, intended to minimize required sample volumes, is a device with which a total sample volume of 1 microL can be dispensed in the form of 1000 identical aliquots. Any number of such nanoliter aliquots can be taken if larger samples are needed. The second new tool is one for detecting anions or cations separated by ion chromatography. Unlike conventional conductometric detectors used in ion chromatography, the new system offers potential sensitivities in the sub-microgram per liter range and useful operating ranges up to 100 mg/L. The third tool is a scheme for background correction in atomic absorption spectrometry; the new technique requires no special auxiliary sources or double-beam optics. Finally, fluorescence time-decay curves and fluorescence lifetimes are shown to be able to overcome the effects of diffusional quenching and scattering resulting from turbidity of solutions in clinical fluorometry.

Liquid-chromatographic analysis for common tricyclic antidepressant drugs and their metabolites in serum or plasma with the technicon "FAST-LC" system.

1981 ◽  
Vol 27 (6) ◽  
pp. 849-855 ◽  
Author(s):  
S J Bannister ◽  
S van der Wal ◽  
J W Dolan ◽  
L R Snyder
Keyword(s):  
High Performance ◽  
Antidepressant Drugs ◽  
Total Sample ◽  
Sample Volume ◽  
Tricyclic Antidepressant ◽  
Tricyclic Antidepressant Drugs ◽  
Liquid Chromatographic Analysis ◽  
Double Extraction ◽  
Liquid Chromatographic ◽  
Total Sample Volume

Abstract We describe a single procedure for assay of seven tricyclic antidepressant drugs and metabolites in serum or plasma: protriptyline, nortriptyline, amitriptyline, desmethyldoxepin, doxepin, desipramine, and imipramine. With the Technicon "FAST-LC" system, samples are aspirated directly into the unit and pretreated via double extraction; the concentration of each drug is then determined by "high-performance" liquid chromatography. Final chromatograms are monitored at 205 nm, at analysis rates of 7.5 samples/h. Concentration and absorbance are linearly related for each drug from 0 to 1400 micrograms/L. Day-to-day CVs averaged 5 to 6% for each drug, and there is good correlation of FAST-LC values with those obtained by gas-chromatographic methods. Total sample volume is 750 microliters.

scholarly journals Miami Natural Radiocarbon Measurements I

Radiocarbon ◽  
1962 ◽  
Vol 4 ◽  
pp. 51-56 ◽  
Author(s):  
H. Göte Östlund ◽  
Albert L. Bowman ◽  
Gene A. Rusnak
Keyword(s):  
Geographic Location ◽  
Cosmic Ray ◽  
Concrete Block ◽  
Total Sample ◽  
Sample Volume ◽  
Active Volume ◽  
Coral Rock ◽  
Counting Tube ◽  
One Year ◽  
Total Sample Volume

The construction of the dating apparatus started in the summer of 1960 and was completed one year later. The laboratory is located on the bottom floor of a three-story concrete-block building which has two thin concrete floors on concrete beams above the shield. The building is underlain by carbonate mud and coral rock. The geographic location is 25° 43.9′ N Lat, 80° 09.8′ W Long and only a few feet above sealevel. We use a proportional-counting tube with an active volume of 1 L, and a total sample volume of 1.30 L, filled with purified CO2to a pressure of 225 cm Hg (3 atm) at 25°C. The tube is made of copper with brass ends and quartz insulators. The shielding consists of 20 cm of iron, 10 cm of paraffin with boric acid, 2.5 cm of selected lead (Östlund, 1961), and cosmic ray guard counters. The room is air-conditioned but no additional precautions have been taken to exclude outdoor dust.

Cerebrospinal fluid sampling from guineapigs: Sample volume-related changes in protein concentration in control animals and animals in the relapsing phase of chronic relapsing experimental allergic encephalomyelitis

1984 ◽  
Vol 18 (1) ◽  
pp. 36-39 ◽  
Author(s):  
A. J. Suckling ◽  
H. Reiber
Keyword(s):  
Cerebrospinal Fluid ◽  
Experimental Allergic Encephalomyelitis ◽  
Protein Concentration ◽  
Total Sample ◽  
Sample Volume ◽  
Albumin Concentration ◽  
Allergic Encephalomyelitis ◽  
Total Sample Volume ◽  
Experimental Allergic

Cerebrospinal fluid (CSF) was removed from guineapigs by puncture of the cisterna magna and the total sample volume of 200-360 µl divided into 40 µl aliquots. After determination of albumin and IgG in these CSF aliquots it was found that successive samples gave different results. In general, up to 100 µl CSF could be removed before the protein concentration began to increase. In animals with chronic relapsing experimental allergic encephalomyelitis (CR-EAE) the rise in albumin concentration was accompanied by a corresponding fall in the number of white cells in later samples.

On-line liquid-chromatographic analysis for drugs in serum with the Technicon "FAST-LC" system: performance data for theophylline and for four commonly used anticonvulsants and their metabolites.

1980 ◽  
Vol 26 (7) ◽  
pp. 871-880
Author(s):  
J W Dolan ◽  
S van der Wal ◽  
S J Bannister ◽  
L R Snyder
Keyword(s):  
High Performance ◽  
Total Sample ◽  
Sample Volume ◽  
Active Metabolites ◽  
Serum Samples ◽  
New Instrument ◽  
On Line ◽  
Liquid Chromatographic Analysis ◽  
Liquid Chromatographic ◽  
Total Sample Volume

Abstract We describe a new instrument for use in assay of therpeutic drugs in serum by "high-performance" liquid chromatography, the "FAST-LC" system (Technicon). Serum samples are aspirated directly into the unit, extracted with solvent, and the evaporated and redissolved extract is injected onto a chromatographic column. We illustrate the performance of the system by assays in serum for theophylline and four anticonvulsants (primidone, phenobarbital, phenytoin, and carbamazepine) plus two of their active metabolites (phenylethylmalonamide and carbamazepine epoxide). For theophylline, final chromatograms are monitored at 270 nm, at analysis rates of 10/h. Concentration and absorbance are linearly related from 0 to 130 mg of theophylline per liter. For the anticonvulsants, chromatograms are monitored at 200 nm, at analysis rates of 7.5/h. The six individual determinations are each linear beyond the therapeutic range. For both drug panels, day-to-day CV's were 4 to 6%. Results correlate well with those by enzyme immunoassay. A total sample volume of 150 microL is required.

scholarly journals Reverse transcription PCR to detect low density malaria infections

2021 ◽  
Vol 6 ◽  
pp. 39
Author(s):  
Peter Christensen ◽  
Zbynek Bozdech ◽  
Wanitda Watthanaworawit ◽  
Laurent Renia ◽  
Benoit Malleret ◽  
...  
Keyword(s):  
Reverse Transcription ◽  
Malaria Elimination ◽  
Malaria Diagnosis ◽  
Sample Volume ◽  
Malaria Prevalence ◽  
Low Density ◽  
Rt Pcr ◽  
Reverse Transcription Pcr ◽  
Increased Sensitivity ◽  
Downstream Analysis

Background: Targeted malaria elimination strategies require highly sensitive tests to detect low density malaria infections (LDMI). Commonly used methods for malaria diagnosis such as light microscopy and antigen-based rapid diagnostic tests (RDTs) are not sensitive enough for reliable identification of infections with parasitaemia below 200 parasites per milliliter of blood. While targeted malaria elimination efforts on the Thailand-Myanmar border have successfully used high sample volume ultrasensitive quantitative PCR (uPCR) to determine malaria prevalence, the necessity for venous collection and processing of large quantities of patient blood limits the widespread tractability of this method. Methods: Here we evaluated a real-time reverse transcription PCR (RT-PCR) method that reduces the required sample volume compared to uPCR. To do this, 304 samples collected from an active case detection program in Kayin state, Myanmar were compared using uPCR and RT-PCR. Results: Plasmodium spp. RT-PCR confirmed 18 of 21 uPCR Plasmodium falciparum positives, while P. falciparum specific RT-PCR confirmed 17 of the 21 uPCR P. falciparum positives. Combining both RT-PCR results increased the sensitivity to 100% and specificity was 95.1%. Conclusion: Malaria detection in areas of low transmission and LDMI can benefit from the increased sensitivity of ribosomal RNA detection by RT-PCR, especially where sample volume is limited. Isolation of high quality RNA also allows for downstream analysis of malaria transcripts.

scholarly journals Sample-displacement correction for whole-pattern profile fitting of powder diffraction data collected in capillary geometry

2010 ◽  
Vol 44 (1) ◽  
pp. 60-64 ◽  
Author(s):  
Nicola Vivienne Yorke Scarlett ◽  
Matthew R. Rowles ◽  
Kia S. Wallwork ◽  
Ian C. Madsen
Keyword(s):  
Diffraction Data ◽  
Large Diameter ◽  
Total Sample ◽  
Sample Volume ◽  
Oriented Growth ◽  
Peak Splitting ◽  
Profile Fitting ◽  
Two Samples ◽  
Reaction Vessels ◽  
Capillary Walls

Recentin situexperimentation at the Australian Synchrotron resulted in the nucleation and crystallization of material on the walls of the capillary reaction vessels. This lining of the capillary walls, without filling the bulk of the capillary volume, produced an artefact in the diffraction data due to sample displacement across the capillary. In effect, the experiment was examining simultaneously two samples displaced by equal and opposite amounts from the diffractometer centre. This was exaggerated by the fact that large-diameter (1 mm) capillaries had been used in order to increase the total sample volume and hence maximize the amount of material formed and examined. The effect of this displacement was to shift the diffraction peaks simultaneously to both lower and higher angles than their `ideal' positions, causing peak splitting in many instances. A model has been developed which considers the sample as being effectively two flat plate samples, thus allowing for correction through the use of sample displacement. An additional problem resulted from the oriented growth of the material on the capillary walls, producing preferred orientation in the observed data. The correction model can also be extended to model such anisotropic peak splitting caused by this preferential orientation of the crystallites on the capillary wall.

scholarly journals The use of X-ray computed microtomography for graptolite detection in rock based on core internal structure visualization

2017 ◽  
Vol 67 (2) ◽  
pp. 299-306 ◽  
Author(s):  
Łukasz Kaczmarek ◽  
Anna Kozłowska ◽  
Michał Maksimczuk ◽  
Tomasz Wejrzanowski
Keyword(s):  
Numerical Models ◽  
Volume Ratio ◽  
Total Sample ◽  
Sample Volume ◽  
Baltic Basin ◽  
Visible Image ◽  
X Ray ◽  
Reservoir Rocks ◽  
Computed Microtomography ◽  
X Ray Computed

Abstract This paper presents for the first time X-ray computed microtomography (μCT) analysis as a technique for Silurian graptolite detection in rocks. The samples come from the Jantar Bituminous Claystones Member of the Opalino core, Baltic Basin, northern Poland. Images were obtained with spatial resolution of 25 μm, which enabled the authors to create a 3-D visualization and to calculate the ratio of fissure and graptolite volume to the total sample volume. A set of μCT slices was used to create a 3-D reconstruction of graptolite geometry. These μCT slices were processed to obtain a clearly visible image and the volume ratio. A copper X-ray source filter was used during exposure to reduce radiograph artifacts. Visualization of graptolite tubaria (rhabdosomes) enabled Demirastrites simulans to be identified. Numerical models of graptolites reveal promising applications for paleontological research and thus for the recognition and characterization of reservoir rocks.

Trace analysis of glyphosate in water by capillary electrophoresis on a chip with high sample volume loadability

2012 ◽  
Vol 35 (5-6) ◽  
pp. 674-680 ◽  
Author(s):  
Michal Horčičiak ◽  
Marián Masár ◽  
Róbert Bodor ◽  
Ladislav Danč ◽  
Peter Bel
Keyword(s):  
Capillary Electrophoresis ◽  
Trace Analysis ◽  
Sample Volume
Sign in / Sign up

Export Citation Format

Share Document