THE INFLUENCE OF SAMPLE COMPOSITION ON MAGNESIUM, CADMIUM, AND LEAD INTENSITY RATIOS AS RADIATED FROM A SPARK SOURCE

1942 ◽  
Vol 20a (4) ◽  
pp. 39-47 ◽  
Author(s):  
G. O. Langstroth ◽  
K. B. Newbound
Keyword(s):  
Internal Standard ◽  
Potassium Nitrate ◽  
Standard Samples ◽  
Potassium Tartrate ◽  
Effective Discharge ◽  
Discharge Temperature ◽  
Sample Composition ◽  
Obvious Generalization ◽  
Intensity Ratios ◽  
Cadmium And Lead

Marked variations have been observed in the relative intensities of magnesium, cadmium, and lead lines on the addition of various amounts of foreign substances to standard samples and excitation in a condensed spark source. The changes in the interspectra intensity ratios depended on the nature and amount of the added substances, as well as on the elements under consideration. In many instances buffering of the samples with sodium potassium tartrate or potassium nitrate did not reduce the variations. The behaviour cannot be explained solely on the basis of changes in an "effective" discharge temperature. The data permit no obvious generalization that might be helpful as a criterion for the choice of internal standard elements and buffer substances.

X-Ray Spectrographic Analysis of the 3-d Transition Metal Corrosion Products Using Potassium Bromide Disks*

1963 ◽  
Vol 7 ◽  
pp. 590-597
Author(s):  
L. A. Schluter
Keyword(s):  
Pulse Height ◽  
Weight Ratio ◽  
Internal Standard ◽  
Corrosion Products ◽  
Metal Corrosion ◽  
Small Samples ◽  
Bragg Angle ◽  
X Ray ◽  
Calibration Curves ◽  
Intensity Ratios

AbstractA technique has been developed for quantitative analysis of the major constituents in small samples (less than 0.1 g) of corrosion products found On various missile parts. The technique was developed primarily to aid in interpretation of X-ray diffraction patterns of multicomponent corrosion products. The corrosion sample is mixed with KBr and the mixture is pressed into a disk in the same fashion commonly used in infrared work. The Br Kβ1 line serves as an internal standard. Intensities of the element's Kα line and the internal standard are established by scanning through the appropriate Bragg angle and recording peak heights on a strip-chart recorder. A xenon-filled proportional detector and a pulse-height analyzer were used.The percent of an element is determined by references to calibration curves which relate intensity ratios to weight ratios for the 3-d transition metals. The oxides of the metals were used in the preparation of the calibration curves. The weight ratio vs. intensity ratio relationship is linear over the weight ratio range 0.01 to 0.11. Data were collected using an air path and a helium path; the higher intensity ratios obtained with, the helium path, and the dependence of intensity on atomic number are illustrated. A comparison is made between the intensity ratios in a KBr matrix and in a NaBr matrix. The technique developed requires about 15 min sample preparation time.

scholarly journals DEVELOPMENT AND VALIDATION OF A HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY METHOD FOR DETERMINING METFORMIN HYDROCHLORIDE IN DRIED BLOOD SPOTS

2018 ◽  
Vol 10 (1) ◽  
pp. 126
Author(s):  
Yahdiana Harahap ◽  
Prastiwi Arum Sari ◽  
Catur Jatmika
Keyword(s):  
Internal Standard ◽  
Dried Blood Spots ◽  
In Vivo Studies ◽  
Array Detector ◽  
Metformin Hydrochloride ◽  
Standard Samples ◽  
Chromatography Method ◽  
Column Temperature ◽  
Blood Spots ◽  
Metformin Hcl

Objective: This study aimed to develop an analytical method for determining metformin concentrations in human dried blood spots (DBS) usingoptimal chromatographic conditions and DBS preparation methods and validate the analytical methods.Methods: Analysis metformin HCl performed using C-18 columns (250 mm × 4.6 mm) at a column temperature of 40°C with a mobile phase acetonitrilephosphate buffer (40:60% v/v) at pH 7.0 using a flow rate of 0.8 mL/min, a photodiode array detector at a wavelength of 234 nm, and atorvastatincalcium as an internal standard. Samples were prepared by protein precipitation with 60% methanol and then drying using nitrogen gas at 60°C for15 min before reconstituting in 200 μL of the mobile phase.Results: Invalidation procedures, the present methods met the acceptance criteria stated in the EMEA Bioanalytical Guideline 2011. The method wasalso linear at the concentration range of 25.0–5000.0 ng/mL (r=0.9997).Conclusion: The developed method for determination of metformin HCl in DBS sample was valid with a concentration range of 25.0–5000.0 ng/mLand can be applied to in vivo studies.

Analysis of Beryllium Metal and its Compounds by Optical Emission Spectrography

1966 ◽  
Vol 20 (1) ◽  
pp. 44-46 ◽  
Author(s):  
L. Carpenter ◽  
R. W. Lewis ◽  
K. A. Hazen
Keyword(s):  
Barium Carbonate ◽  
Cupric Oxide ◽  
Internal Standard ◽  
Optical Emission ◽  
Beryllium Oxide ◽  
The Other ◽  
Germanium Oxide ◽  
Intensity Ratios ◽  
Dc Arc ◽  
Beryllium Metal

Eighteen elements are determined in beryllium from 5 to 1000 ppm by a dc-arc method. Samples are dissolved in hydrochloric acid, converted thermally to beryllium oxide, then mixed with graphite and barium carbonate for determining calcium, mixed with cupric oxide for determining boron and molybdenum, and mixed with graphite and germanium oxide for determining the other 15 elements. Spectral transmittances of analytical and internal standard lines are converted to relative-intensity ratios which are plotted against concentrations of standards to form curves from which concentrations of impurities are read.

X-Ray Fluorescence Spectrometric Determination of Rare Earths in Plutonium

1968 ◽  
Vol 22 (5) ◽  
pp. 434-437 ◽  
Author(s):  
E. A. Hakkila ◽  
R. G. Hurley ◽  
G. R. Waterbury
Keyword(s):  
Rare Earths ◽  
Internal Standard ◽  
Internal Standard Method ◽  
X Rays ◽  
Measured Intensity ◽  
X Ray ◽  
Low Concentrations ◽  
Relative Standard ◽  
Intensity Ratios

Two methods were evaluated for determining rare earths in plutonium: (1) For the lighter rare earths ( Z≦66), or low concentrations of the heavier rare earths, an adjacent rare earth was added as a carrier and also as an internal standard, the rare earths were separated from plutonium by fluoride precipitation, and the measured intensity ratios for the sample and for solutions having known concentrations were compared. The Lβ1 x-rays were measured for the lighter rare earths and the Lα1 x rays for the remaining lanthanides. (2) For the heavier rare earths ( Z>66), the Lα1 x-ray intensities were measured from a nitric acid solution of the sample and compared to intensities obtained for solutions having known concentrations. The minimum concentrations that could be measured with a relative standard deviation no greater than 4% by the separation internal standard method varied from approximately 0.5% for lanthanum to 0.01% for lutetium. The direct measurement of x-ray intensity was much less sensitive. Applicability of the methods was shown by successful analyses of plutonium alloys containing dysprosium, thulium, or lutetium.

The accuracy of X-ray diffraction methods for determining mineral mixtures

1985 ◽  
Vol 49 (353) ◽  
pp. 531-538 ◽  
Author(s):  
Covadonga Brime
Keyword(s):  
Internal Standard ◽  
Diffraction Method ◽  
Mass Attenuation Coefficient ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sample Composition ◽  
Empirical Determination ◽  
Mineral Mixtures ◽  
Mass Attenuation

AbstractAn X-ray diffraction method has been successfully applied to the quantitative determination of mineral mixtures. The absorptive properties of the samples and the number of components determine the analytical procedure to be used. The methods described (external standard plus empirical determination of the mass attenuation coefficient) provides an accurate and rapid alternative to the direct measurement of the mass attenuation, Compton diffusion or internal standard methods. The relative accuracy obtained is of the order of 10% at the 0.1% level, independent of the sample composition.

scholarly journals Gas Chromatographic Determination of Acephate in Technical Material and Soluble Powder Formulations: Collaborative Study

1997 ◽  
Vol 80 (3) ◽  
pp. 459-463
Author(s):  
Martin F Kovacs ◽  
H Michael Wehr ◽  
B A Belkind ◽  
J Stein ◽  
O O Bennett ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Broad Spectrum ◽  
Collaborative Study ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Reference Standard ◽  
Standard Samples ◽  
Relative Standard ◽  
Technical Material

Abstract A gas chromatographic (GC) method was developed for quantitation of acephate (Orthene) in technical material and soluble powder formulations. Acephate is an organophosphate with broad spectrum contact and systemic insecticidal properties. Fourteen collaborators from 8 countries participated in a collaborative study of the method. Collaborators were provided with the method; samples of technical acephate and formulated soluble powder containing 95-99% and 71-75% acephate, respectively; an acephate reference standard; and internal standard. Samples were weighed, diluted to volume with internal standard, and quantitated by using GC peak area ratios. Relative standard deviation values for reproducibility (RSDR) were 1.03-2.55 for 95-99% technical acephate and 1.36-2.73 for formulated soluble powder containing 71-75% acephate. The GC method for determination of acephate in technical material and soluble powder formulations has been adopted by AOAC INTERNATIONAL

QUANTITATIVE ANALYSIS OF POWDERED SAMPLES COMPOSED OF HIGH-Z ELEMENTS

1998 ◽  
Vol 08 (02n03) ◽  
pp. 185-202 ◽  
Author(s):  
K. SERA ◽  
S. FUTATSUGAWA
Keyword(s):  
Particle Size ◽  
Quantitative Analysis ◽  
Cross Sections ◽  
Internal Standard ◽  
Waste Incineration ◽  
Effective Thickness ◽  
Photon Absorption ◽  
Internal Standard Method ◽  
Correction Factors ◽  
Standard Samples

A method of quantitative analysis which is capable of analyzing powdered samples consisting of high-Z elements, such as ash, soil and aerosol, is developed. It is confirmed that an internal standard method using a powdered internal standard, which has almost the same particle size as that of a sample, gives quantitative values of concentration with satisfactory accuracy and reproducibility. It was successfully applied to standard samples such as NIST-Urban particulate matter (1648), GBW-Tibet soil (08302), BCR-City waste incineration ash (0497) and also to a practical fly-ash sample. As a result, it is found that the effect of self-absorption in the target is not negligible even for samples whose particle size is less than 4 μm, and a method of correcting it is established. Firstly, the effective thickness for self-absorption is estimated by comparing peak yields of a certain element for two measuring conditions of beam irradiation from the surface and from the back of the target. The correction factors can be estimated by using the effective thickness, values of concentration of principal elements and their photon absorption cross sections. For practical samples whose compositions are unknown, it is confirmed that accurate correction coefficients can be derived by carrying out an iterative calculation until a self-consistent solution between values of concentration of the main constituents and the correction factors is obtained.

scholarly journals 192 Terpenes as antinutritive chemicals in red cedar

2019 ◽  
Vol 97 (Supplement_1) ◽  
pp. 77-77
Author(s):  
Raquel Lourencon ◽  
Steven P Hart ◽  
Terry A Gipson ◽  
Bob Adams ◽  
Davila Rassi
Keyword(s):  
Gas Chromatography ◽  
Steam Distillation ◽  
Internal Standard ◽  
Juniperus Virginiana ◽  
Standard Samples ◽  
Red Cedar ◽  
Peak Areas ◽  
Terpene Content ◽  
Methyl Decanoate ◽  
Significant Factors

Abstract At some research sites goats aggressively consumed red cedar (Juniperus virginiana) throughout the year, while at other sites goats consumed little cedar, although they consumed more cedar in winter. It was hypothesized that differences in red cedar intake may be caused by terpenes. The purpose of this study was to measure terpenes in cedar needles at different locations and times of the year. Ninety-one samples of red cedar needles were obtained from four locations (Langston, OK; Midwest City, OK; Mannford, OK; Neosho, MO) at monthly intervals over a 2-yr period. Needles were manually stripped from branches at approximately 1.5 m high from at least 25 plants at each location. Sixty grams of cedar needles were extracted by steam distillation for 2 h. Some samples were exhaustively extracted for a further 6 h to calculate recovery (45.7%). Two mL of diethyl ether were added, containing 1 mg/mL of methyl decanoate (internal standard), samples were vortexed and the ether was dried with a stream of nitrogen. Samples were subjected to gas chromatography for terpenes. The total amount of terpenes (mg/g DM) was calculated as the sum of peak areas/peak area of the internal standard x 2 mg internal standard/ 0.457/ dried weight of cedar needles. Months were categorized as season. Data were analyzed using the SAS GLM procedure with factors of season, year, and location. Neither season (P > 0.8) nor location (P > 0.25) nor the interaction (P > .9) were significant factors determining total terpene content of red cedar. Concentration of total terpenes for Langston was 20.8, Mannford 18.4, Neosho 15.2, and OKC 18.6 mg/g DM. Concentration by season was Fall 17.1, Spring 18.6, Summer 17.5, and Winter 19.7 mg/g DM. Total terpene concentration does not seem to be a factor affecting red cedar consumption by goats.

scholarly journals Quantification of Free Sialic Acid in Urine by HPLC–Electrospray Tandem Mass Spectrometry: A Tool for the Diagnosis of Sialic Acid Storage Disease

2004 ◽  
Vol 50 (2) ◽  
pp. 403-409 ◽  
Author(s):  
Fredoen Valianpour ◽  
Nicolaas G G M Abeling ◽  
Marinus Duran ◽  
Jan G M Huijmans ◽  
Willem Kulik
Keyword(s):  
Sialic Acid ◽  
Limit Of Detection ◽  
Internal Standard ◽  
Reference Method ◽  
Spectrometric Analysis ◽  
Ph Effects ◽  
Tandem Mass ◽  
Standard Samples ◽  
Tandem Mass Spectrometric ◽  
Free Sialic Acid

Abstract Background: Sialic acid storage diseases (SSDs) are severe autosomal recessive neurodegenerative disorders caused by a transport defect across the lysosomal membrane, which leads to accumulation of sialic acid in tissues, fibroblasts, and urine. Defective free sialic acid transport can be established by quantification of free sialic acid in urine. Methods: Urine sample size was adjusted to the equivalent of 100 nmol of creatinine. After addition of 2-keto-3-deoxy-d-glycero-d-galactonononic acid as internal standard, samples were diluted with water to an end volume of 250 μL. We used 10 μL for HPLC–tandem mass spectrometric analysis in the negative electrospray ionization mode, monitoring transitions m/z 308.3→m/z 86.9 (sialic acid) and m/z 267.2→m/z 86.9 (internal standard). The overall method was validated and studied for ion suppression, interfering compounds, and pH effects. Samples from controls (n = 72) and SSD patients (n = 3) were analyzed. Results: The limit of detection was 3 μmol/L. Intraassay imprecision (CV; n = 10) was 6%, 3%, and 2% at 30, 130, and 1000 mmol/mol creatinine, respectively; corresponding interassay CV (n = 10) were 5%, 5%, and 2%. Recovery was 109% (100–1000 mmol/mol creatinine). The mean (SD) [range] excretion rates (mmol/mol creatinine) were 31.3 (16.6) [0.7–56.9] at 0–1 year (n = 20), 21.2 (9.8) [6.3–38.3] at 1–3 years (n = 15), 14.4 (8.2) [1.7–32.9] at 3–10 years (n = 25), and 4.6 (2.6) [0–9.8] above age 10 years (n = 12). SSD patients 1.2, 3.9, and 12 years of age had concentrations of 111.5, 54.2, and 36.1 mmol/mol creatinine, respectively. Conclusions: The HPLC-tandem MS method for free sialic acid in urine is more rapid, accurate, sensitive, selective, and robust than earlier methods and may serve as a candidate reference method for free sialic acid in diagnosis of SSD.

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