Single Stable Reagent (Arsenazo III) for Optically Robust Measurement of Calcium in Serum and Plasma

1992 ◽  
Vol 38 (6) ◽  
pp. 904-908 ◽  
Author(s):  
N O Leary ◽  
A Pembroke ◽  
P F Duggan
Keyword(s):  
Arsenazo Iii ◽  
External Quality Control ◽  
External Quality ◽  
Mean Values ◽  
Standard Curve ◽  
Control Schemes ◽  
Stable Reagent ◽  
Good Agreement ◽  
Positive Interference

Abstract We describe a method based on a single stable reagent for the determination of calcium in serum and plasma with use of Arsenazo III, 200 mumol/L in 50 mmol/L 1,4-piperazinediethanesulfonic acid (PIPES) buffer. The method showed significant positive interference in plasma at pH less than 6.6 because of the precipitation of fibrinogen, which was eliminated by increasing the pH to 6.8. The assay showed no interference from as much as 600 mumol of bilirubin and 12 g of hemoglobin per liter when applied in a simple monochromatic procedure at 660 nm. The standard curve for calcium was linear from 0 to 5.0 mmol/L. Addition of Intralipid at concentrations greater than 3 g/L demonstrated positive interference, which could be eliminated by using a 700-nm blanking wavelength. The procedure showed good agreement with all-method mean values from two external quality-control schemes.

scholarly journals The Schemes of External Quality Control in Laboratory Medicine in the Balkans

2007 ◽  
Vol 26 (3) ◽  
pp. 245-247
Author(s):  
Petros Karkalousos
Keyword(s):  
Quality Control ◽  
Scientific Community ◽  
Clinical Chemistry ◽  
Laboratory Medicine ◽  
External Quality Control ◽  
External Quality ◽  
The Balkans ◽  
Control Schemes ◽  
Balkan Countries ◽  
Balkan Region

The Schemes of External Quality Control in Laboratory Medicine in the Balkans There are many differences between the national External Quality Control Schemes all around Europe, but the most important ones are certainly those between the countries of the Balkan region. These differences are due to these countries' different political and financial development, as well as to their tradition and the development of clinical chemistry science in each one. Therefore, there are Balkan countries with very developed EQAS and others where there is no such a scheme. Undoubtedly, the scientific community in these countries wants to develop EQAS despite of the financial and other difficulties.

Spectrophotometric Determination of Phosphorus in Certifiable Straight Color Additives: Collaborative Study

1981 ◽  
Vol 64 (4) ◽  
pp. 808-813
Author(s):  
Wallace S Brammell ◽  
◽  
C Arozarena ◽  
J Hunter ◽  
H G Kiernan ◽  
...  
Keyword(s):  
Total Phosphorus ◽  
Phosphorus Content ◽  
Collaborative Study ◽  
Mean Values ◽  
Total Phosphorus Content ◽  
Standard Curve ◽  
Coefficients Of Variation ◽  
Molybdovanadophosphoric Acid ◽  
Acid Reagent

Abstract A simple and rapid spectrophotometric method was developed for determining the total phosphorus content of certifiable straight color additives. The dye sample is mixed with a cellulose powder and MgO mixture, and ashed at 500°C in a small Pyrex beaker in a muffle furnace. The ash is dissolved in vanadomolybdic acid reagent and filtered through glass wool, and the absorbance of the resulting yellow molybdovanadophosphoric acid solution is measured at 400 nm. The total phosphorus content of the sample, expressed as percent Na3PO4, is determined from a standard curve. Recovery of phosphorus added as KH2PO4 to 39 different dyes in amounts equivalent to 0.300% Na3PO4 ranged from 95.3 to 106.8%, averaging 100.6%. In the collaborative study, 7 laboratories successfully performed duplicate analyses of 6 different dyes (D&C Orange No. 5, D&C Yellow No. 8, FD&C Blue No. 2, FD&C Red No. 3, FD&C Red No. 40, and FD&C Green No. 3). The mean values found ranged from 0.325 to 6.86% Na3PO4. In general, the accuracy and reproducibility of the method were satisfactory, with single determination coefficients of variation ranging from 3.76 to 9.60%. The method was adopted official first action.

scholarly journals Energy-dispersive spectroscopy for the quantitative determination of the major chemical elements in milk

2021 ◽  
Vol 10 (10) ◽  
pp. e280101018910
Author(s):  
Igor Lima de Paula ◽  
Isis Rodrigues Toledo Renhe ◽  
Rodrigo Stephani ◽  
Ítalo Tuler Perrone ◽  
Antônio Fernandes de Carvalho ◽  
...  
Keyword(s):  
Quantitative Determination ◽  
Chemical Elements ◽  
Raw Milk ◽  
Energy Dispersive ◽  
Mean Values ◽  
Milk Samples ◽  
Application Potential ◽  
Major Chemical ◽  
Good Agreement

The present preliminary study aims at the rapid quantitative determination of the major chemical elements in the ashes of raw milk samples, using energy dispersive X-ray fluorescence spectrometry. The precision of the method was satisfactory (variation coefficient ≤ 5%). The mean values (in mmol·kg-1) obtained from the analysis of 32 raw milk samples showed good agreement with data from the Brazilian and international literature: K (26.1 ± 4.6), Ca (33.8 ± 3.7), P (28.4 ± 2.7), Na (21 ± 3.3) and Mg (4.7 ± 0.5). Residual Cl concentration (19.0 ± 3.3 mmol·kg-1) was lower than expected due to incineration losses. The results suggest a good application potential of the method for other dairy products.

Statistical Diagnostics Emerging from External Quality Control of Real-Time PCR

2004 ◽  
Vol 19 (2) ◽  
pp. 141-146 ◽  
Author(s):  
E. Marubini ◽  
P. Verderio ◽  
C. Casini Raggi ◽  
M. Pazzagli ◽  
C. Orlando
Keyword(s):  
Quality Control ◽  
Real Time ◽  
Real Time Pcr ◽  
Control Charts ◽  
Reference Curve ◽  
External Quality Control ◽  
External Quality ◽  
Standard Curve ◽  
Pcr Products ◽  
Real Time Detection

Besides the application of conventional qualitative PCR as a valuable tool to enrich or identify specific sequences of nucleic acids, a new revolutionary technique for quantitative PCR determination has been introduced recently. It is based on real-time detection of PCR products revealed as a homogeneous accumulating signal generated by specific dyes. However, as far as we know, the influence of the variability of this technique on the reliability of the quantitative assay has not been thoroughly investigated. A national program of external quality assurance (EQA) for real-time PCR determination involving 42 Italian laboratories has been developed to assess the analytical performance of real-time PCR procedures. Participants were asked to perform a conventional experiment based on the use of an external reference curve (standard curve) for real-time detection of three cDNA samples with different concentrations of a specific target. In this paper the main analytical features of the standard curve have been investigated in an attempt to produce statistical diagnostics emerging from external quality control. Specific control charts were drawn to help biochemists take technical decisions aimed at improving the performance of their laboratories. Overall, our results indicated a subset of seven laboratories whose performance appeared to be markedly outside the limits for at least one of the standard curve features investigated. Our findings suggest the usefulness of the approach presented here for monitoring the heterogeneity of results produced by different laboratories and for selecting those laboratories that need technical advice on their performance.

Microencapsulated antibodies in radioimmunoassay. II. Determination of free thyroxine.

1979 ◽  
Vol 25 (9) ◽  
pp. 1561-1563 ◽  
Author(s):  
E P Halpern ◽  
R W Bordens
Keyword(s):  
Serum Antibody ◽  
Free Thyroxine ◽  
Relative Molecular Mass ◽  
Displacement Reaction ◽  
Nylon Membrane ◽  
Mean Values ◽  
Standard Curve ◽  
Significant Difference ◽  
Control Samples

Abstract We describe a method for directly measuring free thyroxine in human serum. Antibody to thyroxine was encapsulated within a semipermeable nylon membrane that excludes substances of relative molecular mass greater than 20,000. The microencapsulated antibody was then presaturated with [125I]thyroxine. Serum incubated with the microcapsules initiated a displacement reaction between free thyroxine and [125I]thyroxine bound to the antibody. The displaced thyroxine was separated from the bound thyroxine by centrifugation and the concentration of free thyroxine determined from a standard curve prepared by use of known amounts of free thyroxine. The within-day coefficient of variation for two control samples was 8.8 and 6.8%; day-to-day precision for the same material was 12.5 and 13.5%. Lipemia, icterus, or hemoglobin had no adverse effect. Interlaboratory evaluation of the procedure revealed no significant difference in mean values for 20 speciments (p greater than 0.05).

The Determination of Total Iron in Venezuelan Laterites: The Investigation of Interferences of Aluminum and Silicon on the Determination of Iron in the Fluoboric-Boric Acid Matrix by Atomic Absorption

1978 ◽  
Vol 32 (1) ◽  
pp. 57-60 ◽  
Author(s):  
J. J. La Brecque ◽  
E. Mendelovici ◽  
R. E. Villalba ◽  
C. C. Bellorin
Keyword(s):  
Boric Acid ◽  
Atomic Absorption ◽  
Total Iron ◽  
Geological Samples ◽  
Iron Determination ◽  
Acid Dissolution ◽  
Standard Curve ◽  
Interference Studies ◽  
Good Agreement

An interference-free atomic absorption method for the determination of total iron in geological samples has been adopted. The method is based on the conventional standard curve technique employing the 386 nm atomic absorption line in the fluoboric-boric acid matrix. The use of the 386 nm line instead of the 248.3 nm line is discussed, as well as the advantages of the hydrofluoric acid dissolution of the sample. A comparison of different methods is given in search of one for routine determinations in this laboratory. Interference studies of aluminum and/or silicon on the iron determination conclude that these interferences do not exist under the conditions of this method. The literature on such interferences is reviewed and they are discussed. The proposed method was used to determine total iron in six reference materials and the results were in good agreement with the reported values. Finally, total iron was determined in a preliminary profile of Venezuelan laterites (ferrouginous bauxites).

scholarly journals Elemental Composition of Norwegian Rivers

1979 ◽  
Vol 10 (2-3) ◽  
pp. 115-140 ◽  
Author(s):  
B. Salbu ◽  
A. C. Pappas ◽  
E. Steinnes
Keyword(s):  
Geometric Mean ◽  
Ore Deposits ◽  
Weighted Mean ◽  
Mean Values ◽  
Marine Deposits ◽  
Water Composition ◽  
Alkaline Earths ◽  
The Individual ◽  
Good Agreement

Instrumental neutron activation analysis has been applied for the determination of up to 40 elements in waters from eleven Norwegian rivers. In order to represent the composition of an average river in the region of Norway and possibly the greater part of the Scandinavian peninsula, weighted mean values are calculated on the basis of geometric mean values and discharge of the individual rivers. Factor analysis shows that Cambro-Silurian sedimentary and vulcanic rocks influence the water composition considerably compared to Precambrian gneisses and granites. An influence of airborne supply is evident in coastal areas. In addition ore deposits are important for Zn and associated elements. Comparison with literature data from Sweden shows good agreement for the elements concerned. The present values concerning alkalies, alkaline earths and halogens are, however, significantly lower than the estimated “world averages”. This is probably due to a low abundance of marine deposits and sedimentary rocks in Scandinavia. Low values are also found for elements which are often associated with particulate matter (Fe, Al, V, Mo, As, Sb, Th, U), while the values obtained for rare earths (La, Ce, Sm) and some additional elements (Sc, Mn, Au) are significantly higher than the estimated “world averages”.

Sign in / Sign up

Export Citation Format

Share Document