Total calcium and magnesium determined in serum with an automated stopped-flow analyzer.

1982 ◽  
Vol 28 (10) ◽  
pp. 2149-2152 ◽  
Author(s):  
M A Koupparis ◽  
E P Diamandis ◽  
H V Malmstadt
Keyword(s):  
Continuous Flow ◽  
Absorption Spectrometry ◽  
Stopped Flow ◽  
Tetraacetic Acid ◽  
Total Calcium ◽  
Serum Samples ◽  
Sample Throughput ◽  
Delay Response ◽  
Analytical Recovery ◽  
Calcium And Magnesium

Abstract We describe the measurement of total calcium and magnesium in serum with an automated microcomputer-controlled stopped-flow analyzer. The calcium method is based on the cresolphthalein complexone procedure, with 2-amino-3-methyl-1-propanol as the alkalinizing agent. The assay, performed on 60-fold prediluted samples, requires 50 microL of serum. Absorbance is measured at 580 nm for 1 s, after a 5-s delay. Response is linearly related to concentration up to 5 mmol/L; analytical recovery averaged 97.8%. Within-day CVs were 0.7 to 1.5%, day-to-day CVs 1.8 to 2.5%. Results compared well with those by continuous-flow Technicon SMA II method. A sample throughput of as many as 260 samples per hour is possible. The magnesium determination, a complexometric procedure, involves magnesium/calmagite complex in an alkaline reagent mixture and ethylene glycol bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid to eliminate calcium interference. Prediluted serum samples are used (100 microL of serum diluted 25-fold), and absorbance at 520 nm is linear with concentration to 50 mg/L. Within-run CVs were 0.5 to 1.1%, and day-to-day 1.3 to 3.8%; analytical recovery was 99.3%. Results compared well with those by atomic absorption spectrometry (r = 0.994). A delay time of 10 and a measurement time of 2.5 s allows for a throughput of as many as 180 samples per hour.

Continuous-flow serum albumin determination by reaction with picrate ions, with use of a flow-through picrate ion electrode.

1981 ◽  
Vol 27 (3) ◽  
pp. 427-430 ◽  
Author(s):  
E P Diamandis ◽  
D S Papastathopoulos ◽  
T P Hadjiioannou
Keyword(s):  
Serum Albumin ◽  
Continuous Flow ◽  
Peak Height ◽  
Ion Concentration ◽  
Screening Tests ◽  
Albumin Concentration ◽  
Serum Samples ◽  
Factors Affecting ◽  
Analytical Recovery ◽  
Flow Through

Abstract An automated potentiometric method for serum albumin determination by use of the picrate/albumin reaction is described. A continuous-flow system and a specially designed flow-through picrate ion electrode were used in making the measurements. Various factors affecting the reaction, such as pH, picrate ion concentration, and reaction time, were studied. Peak height in millivolts and albumin concentration were linearly related in the range 10-70 g/L. Both within-run and day-to-day, the CV for the method was about 2%. Analytical recovery of albumin added to serum samples ranged from 97.0 to 110.3%, averaging 102.2%. Results compare favorably with those by the established bromcresol green method. The proposed method is suitable for routine use and for screening tests.

Evaluation of the Corning 940 Calcium Titrator for Use with Serum and Urine

1975 ◽  
Vol 21 (2) ◽  
pp. 264-267 ◽  
Author(s):  
Earl B Weissman ◽  
Desider A Pragay ◽  
Charles Bishop
Keyword(s):  
Atomic Absorption ◽  
Continuous Flow ◽  
Calcium Concentration ◽  
Atomic Absorption Spectrophotometry ◽  
Tetraacetic Acid ◽  
Total Calcium ◽  
Absorption Spectrophotometry ◽  
Coefficients Of Variation ◽  
Serum And Urine ◽  
High Range

Abstract The Corning 940 Titrator, which measures total calcium concentration by titration with [ethylenebis(oxyethylenenitrilo)]tetraacetic acid, was evaluated for use in a hospital laboratory. Calcium values for patients' sera were about 0.3 mg/dl lower as measured with the Titrator than with the Technicon SMA 12/60 continuous-flow analyzer. A similar bias was evident when the results with the Titrator were compared with those from atomic absorption spectrophotometry. Agreement was better in the low range and worse in the high range. Within-day and between-day coefficients of variation on the Titrator were about 1.5% and 2.5%, respectively. We saw no interference from magnesium, phosphorus, bilirubin, or in the presence of lipemia. At extremely increased hemoglobin concentrations (500 mg/dl), there is a 5% inhibition. Titrator results for patients' urine samples correlated closely (n = 0.999) with those obtained with the SMA 12/60.

A stopped-flow/continuous-flow method for kinetic determinations

1995 ◽  
Vol 309 (1-3) ◽  
pp. 277-282 ◽  
Author(s):  
Yun-Sheng Hsieh ◽  
S.R. Crouch
Keyword(s):  
Continuous Flow ◽  
Stopped Flow ◽  
Flow Method ◽  
Continuous Flow Method

Optimization of Automated Sample Preparation for Vitamin D Determination on a Biomek i7 Workstation

2021 ◽  
pp. 247263032110302
Author(s):  
Anna Bach ◽  
Heidi Fleischer ◽  
Bhagya Wijayawardena ◽  
Kerstin Thurow
Keyword(s):  
Vitamin D ◽  
Sample Preparation ◽  
Reference Method ◽  
Positive Pressure ◽  
Additional Risk Factor ◽  
Serum Samples ◽  
Recovery Rates ◽  
Preparation Methods ◽  
Sample Throughput ◽  
Automated Sample Preparation

Vitamin D belongs to the fat-soluble vitamins and is an integral part of bone metabolism. In the human body, a decreased vitamin D level can be an additional risk factor for diseases like cancer, diabetes, and mental diseases. As a result, an enormous increase in the demand for vitamin D testing has been observed in recent years, increasing the demand for powerful methods for vitamin D determination at the same time. Automation is the key factor in increasing sample throughput. This study compares three fully automated sample preparation methods for the determination of 25(OH)D2 and 25(OH)D3 in plasma and serum samples. Starting from a semiautomated reference method, the method is tested manually and subsequently fully automated on the Biomek i7 Workstation by integrating a centrifuge and a positive pressure extractor into the workstation. Alternatively, the centrifugation for the separation of protein aggregates and supernatant is replaced by a filter plate. Finally, the sample throughput is further increased by using phospholipid removal cartridges. The results show that phospholipid removal significantly increases the recovery rates in liquid chromatography–mass spectrometry. With the phospholipid removal cartridges, recovery rates of 97.36% for 25(OH)D2 and 102.5% for 25(OH)D3 were achieved, whereas with the automated classic automated preparation method, the recovery rates were 83.31% for 25(OH)D2 and 86.54% for 25(OH)D3. In addition to the technical evaluation, the different methods were also examined with regard to their economic efficiency. Finally, the qualitative and quantitative performance of the developed methods is benchmarked with a selected semiautomatic reference method.

scholarly journals Miniaturized Continuous-Flow Digital PCR for Clinical-Level Serum Sample Based on the 3D Microfluidics and CMOS Imaging Device

Sensors ◽  
2020 ◽  
Vol 20 (9) ◽  
pp. 2492
Author(s):  
Bin Li ◽  
Yuanming Li ◽  
Andreas Manz ◽  
Wenming Wu
Keyword(s):  
Continuous Flow ◽  
Pcr Amplification ◽  
Complementary Metal Oxide Semiconductor ◽  
Digital Pcr ◽  
Oxide Semiconductor ◽  
Serum Samples ◽  
Imaging Device ◽  
Loop Area ◽  
Teflon Tube ◽  
3D Microfluidics

In recent years, the development of polymerase chain reaction (PCR) technology has focused on digital PCR, which depends on the microfluidics. Based on continuous-flow microfluidic technology, this paper designed a miniaturized digital PCR amplification system, and greatly reduced the area required for microdroplet generation and reaction. The core rod. made of polydimethylsiloxane (PDMS), was combined with the Teflon tube to form 3D microfluidics, which requires only one heating source to form the temperature difference required for gene amplification. Only two 34 g needles can form and transmit micro-droplets in a 4-fold tapered Teflon tube, which is the simplest method to generate digital PCR droplets as far as we know, which allows the microdroplet generation device to be free from dependence on expensive chips. A complementary metal oxide semiconductor (CMOS) camera was used as a detection tool to obtain fluorescence video for the entire loop area or a specified loop area. In addition, we developed a homebrew for automatic image acquisition and processing to realize the function of digital PCR. This technique realizes the analysis of clinical serum samples of hepatitis B virus (HBV) and obtained the same results as real-time quantitative PCR. This system has greatly reduced the size and cost of the entire system, while maintaining a stable response.

THE DETERMINATION OF CALCIUM AND MAGNESIUM IN BLOOD USING ONE INDICATOR

1959 ◽  
Vol 37 (1) ◽  
pp. 225-229 ◽  
Author(s):  
H. M. Czajkowska Robinson ◽  
J. C. Rathbun
Keyword(s):  
Ethylenediaminetetraacetic Acid ◽  
Total Calcium ◽  
Eriochrome Black T ◽  
End Point ◽  
Acid Titration ◽  
Calcium And Magnesium

A rapid ethylenediaminetetraacetic acid titration for calcium and magnesium in serum requiring 0.1 ml of blood is described. Eriochrome black T is used as the sole indicator and the end point is observed photometrically. After determination of total calcium and magnesium, the calcium is removed as oxalate, the magnesium determined separately, and the calcium obtained by difference. The method is highly reproducible and is sensitive to ± 0.1 mg% of either calcium or magnesium.

scholarly journals Measurement of strontium in serum, urine, bone, and soft tissues by Zeeman atomic absorption spectrometry

1997 ◽  
Vol 43 (1) ◽  
pp. 121-128 ◽  
Author(s):  
Patrick C D’Haese ◽  
Glen F Van Landeghem ◽  
Ludwig V Lamberts ◽  
Vera A Bekaert ◽  
Iris Schrooten ◽  
...  
Keyword(s):  
Renal Failure ◽  
Chronic Renal Failure ◽  
Atomic Absorption Spectrometry ◽  
Atomic Absorption ◽  
Soft Tissues ◽  
Absorption Spectrometry ◽  
Serum Samples ◽  
Tissue Samples ◽  
Triton X

Abstract To study the possible accumulation of Sr in chronic renal failure patients, methods were developed for the determination of the element in serum, urine, bone, and soft tissues by using Zeeman atomic absorption spectrometry. Serum samples were diluted 1:4 with a Triton X-100–HNO3 mixture, whereas urine samples were diluted 1:20 with HNO3. Bone samples were digested with concentrated HNO3 in stoppered polytetrafluoroethylene (Teflon®) tubes, whereas soft tissues were dissolved in a tetramethylammonium hydroxide solution in water. For serum and urine we used matrix-matched calibration curves, whereas bone and tissue samples were measured against aqueous calibrators. Atomization was performed from the wall of pyrolytically coated graphite tubes for all of the matrices under study. Both inter- and intraassay CVs were <6% (n = 12, n = 10, respectively), and the recovery of added analyte was close to 100% for all of the biological matrices under study. Detection limits were 1.2 μg/L (serum), 0.3 μg/L (urine), 0.4 μg/g (bone), and 2.2 ng/g (soft tissues), whereas the sensitivity determined by the slope of the calibration curve, i.e., the amount of Sr producing a 0.0044 integrated absorbance change in signal, was 2.4 pg, 2.4 pg, 3.9 pg, and 2.6 pg for these matrices respectively. We conclude that the present methods are precise and accurate and easily applicable for both routine use and research investigations. They will allow us to study the metabolism of the element in chronic renal failure patients and shed some light on the association that was recently noted between increased bone Sr concentrations and the development of osteomalacia in these individuals.

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