Ion-chromatographic determination of plasma oxalate reexamined

1993 ◽  
Vol 39 (3) ◽  
pp. 537-539 ◽  
Author(s):  
M Petrarulo ◽  
E Cerelli ◽  
M Marangella ◽  
F Maglienti ◽  
F Linari
Keyword(s):  
Detection Limit ◽  
Hydrochloric Acid ◽  
Signal To Noise Ratio ◽  
Sample Pretreatment ◽  
Chromatographic Determination ◽  
Plasma Samples ◽  
Signal To Noise ◽  
Analytical Recovery ◽  
Healthy Persons

Abstract This new procedure for determining oxalic acid in plasma is based on sample deproteinization with hydrochloric acid and acetonitrile and subsequent ion-chromatographic assay of the neutralized supernate. Sample pretreatment produces very clean samples, which ensures long column life. Mean analytical recovery of oxalate (5.0-10.0 mumol/L) added to plasma samples averaged 98.6 +/- 6.2%; imprecision (CV) was 5.2% (at 2.2 mumol/L) and the detection limit was 0.5 mumol/L at a signal-to-noise ratio of 5:1. Ascorbate to oxalate conversion was < 0.2%, indicating that the procedure is free from ascorbate interference. Plasma oxalate concentrations, measured in samples from 31 healthy persons, ranged from 0.8 to 3.4 mumol/L (mean 1.89, SD 0.75 mumol/L), which agrees with results from indirect radioisotopic dilution methods.

Ion-chromatographic determination of L-tartrate in urine samples

1991 ◽  
Vol 37 (1) ◽  
pp. 90-93 ◽  
Author(s):  
Mlchele Petrarulo ◽  
Martino Marangella ◽  
Omalla Bianco ◽  
Franco Linari
Keyword(s):  
Potential Role ◽  
Signal To Noise Ratio ◽  
Standard Procedure ◽  
Dicarboxylic Acids ◽  
Chromatographic Determination ◽  
Signal To Noise ◽  
Coefficients Of Variation ◽  
Analytical Recovery

Abstract We propose using ion chromatography to determine tartrate concentration in urine. A 100-microL sample of urine is diluted and injected into the chromatograph. Tartrate is eluted within 11.5 min as a distinct and well-resolved peak. The sensitivity of the standard procedure (signal-to-noise ratio, 3/1) is 30 mumol/L. The intra-run and interrun coefficients of variation are 2.5% and 4.1%, respectively. Mean analytical recovery of known amounts of added tartrate ranges between 94.2% and 104.0%. We investigated the specificity of the procedure by analyzing urine containing added dicarboxylic acids structurally related to tartrate. The reliability of the procedure makes it suitable for investigating tartrate metabolism, e.g., the potential role of tartrate as an inhibitor of crystallization in calcium nephrolithiasis.

Gas Chromatographic Determination of Propamocarb in Agricultural Commodities

1996 ◽  
Vol 79 (3) ◽  
pp. 769-772 ◽  
Author(s):  
Toshihiro Nagayama ◽  
Maki Kobayashi ◽  
Hiroko Shioda ◽  
Toshio Tomomatsu
Keyword(s):  
Detection Limit ◽  
Diethyl Ether ◽  
Signal To Noise Ratio ◽  
Chromatographic Determination ◽  
Agricultural Commodities ◽  
Signal To Noise ◽  
Aqueous Fraction ◽  
Acetone Water ◽  
Nitrogen Phosphorus

Abstract A simple and efficient gas chromatographic (GC) method is described for quantitative determination of propamocarb in agricultural commodities. Propamocarb is extracted into acetone–water (or acidified solvent for dry products) and then cleaned up by extraction with diethyl ether. The analyte is extracted from the aqueous fraction under basic conditions with diethyl ether and then analyzed by GC with nitrogen–phosphorus detection. The minimum detection limit is 0.01 μg/g in original samples (signal-to-noise ratio > 5). Recovery of propamocarb spiked at 0.1 μg/g into various samples is >75%, except for lettuce (41%).

Determination of Phthalate Esters in Plastic Track Surface Layer Material by Gas Chromatography

2017 ◽  
Vol 726 ◽  
pp. 43-49 ◽  
Author(s):  
Peng Chen ◽  
Dan Hua Xu ◽  
Qing Dan Yuan ◽  
Shi Hua Liu
Keyword(s):  
Gas Chromatography ◽  
Surface Layer ◽  
Detection Limit ◽  
Signal To Noise Ratio ◽  
Phthalate Esters ◽  
Microwave Extraction ◽  
Signal To Noise ◽  
Layer Material ◽  
Track Surface

A method was proposed to simultaneously and rapidly determine the content of five kinds of phthalate esters (DMP, DBP, BBP, DnHP, DOP) in plastic track surface layer material by gas chromatography (GC) with the external standard,and the method was first proposed. The sample pretreatment method was microwave-assisted extracted using ethyl acetate as the solvent. Discussed the effects of extraction conditions on the extraction efficiency, microwave extraction time was 30 minutes, microwave extraction temperature was 100°C,the volume of ethyl acetate was 15mL. The results showed that there was a good linear relationship in range of 0.040 to 50 mg/L(R2 was 0.9987-0.9994). The average recoveries of standard addition for five kinds of phthalate esters were between 83.83% and 101.02%, and the relative standard derivations (RSDs (n=6)) ranged from 0.95% to 4.73%. The three times of signal to noise ratio (3 S/N) was used to calculate the detection limit of the method , and the detection limit was 2.5-3.0 mg/kg. The ten times of signal to noise ratio (10 S/N) was used to calculate the quantitation limit of the method, and the limit of quantitation was 8.5-10 mg/kg. This method is simple, effective and suitable for the determination of phthalate esters in plastic track surface layer material.

Determination of the Best Emulsion for the Microscopy of Crystals

1981 ◽  
Vol 39 ◽  
pp. 32-33
Author(s):  
David A. Grano ◽  
Kenneth H. Downing
Keyword(s):  
Spatial Frequency ◽  
Information Transfer ◽  
Signal To Noise Ratio ◽  
Experimental Situation ◽  
Photographic Emulsion ◽  
Modulation Transfer ◽  
Signal To Noise ◽  
Frequency Space ◽  
Noise Ratio

The retrieval of high-resolution information from images of biological crystals depends, in part, on the use of the correct photographic emulsion. We have been investigating the information transfer properties of twelve emulsions with a view toward 1) characterizing the emulsions by a few, measurable quantities, and 2) identifying the “best” emulsion of those we have studied for use in any given experimental situation. Because our interests lie in the examination of crystalline specimens, we've chosen to evaluate an emulsion's signal-to-noise ratio (SNR) as a function of spatial frequency and use this as our critereon for determining the best emulsion.The signal-to-noise ratio in frequency space depends on several factors. First, the signal depends on the speed of the emulsion and its modulation transfer function (MTF). By procedures outlined in, MTF's have been found for all the emulsions tested and can be fit by an analytic expression 1/(1+(S/S0)2). Figure 1 shows the experimental data and fitted curve for an emulsion with a better than average MTF. A single parameter, the spatial frequency at which the transfer falls to 50% (S0), characterizes this curve.

scholarly journals Remote whispering metamaterial for non-radiative transceiving of ultra-weak sound

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jin Zhang ◽  
Wei Rui ◽  
Chengrong Ma ◽  
Ying Cheng ◽  
Xiaojun Liu ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Detection Limit ◽  
Free Space ◽  
Signal To Noise Ratio ◽  
Resonance Energy Transfer ◽  
Information Leakage ◽  
Resonance Energy ◽  
Acoustic Analogy ◽  
Signal To Noise ◽  
Airborne Sound

AbstractTransceiving ultra-weak sound typically relies on signal pre-amplification at the transmitting end via active electro-acoustic devices, which inherently perturbs the environment in the form of noise that inevitably leads to information leakage. Here we demonstrate a passive remote-whispering metamaterial (RWM) enabling weak airborne sound at audible frequencies to reach unprecedented signal enhancement without altering the detected ambient soundscape, which is based on the extraordinary scattering properties of a metamaterial formed by a pair of self-resonating subwavelength Mie meta-cavities, constituting the acoustic analogy of Förster resonance energy transfer. We demonstrate efficient non-radiative sound transfer over distances hundreds times longer than the radius of the meta-cavities, which enables the RWM to recover weak sound signals completely overwhelmed by strong noise with enhanced signal-to-noise ratio from −3 dB below the detection limit of 0 dB in free space to 17.7 dB.

Liquid Chromatographic Determination of Sulfamoyldapsone in Swine Tissues

1987 ◽  
Vol 70 (6) ◽  
pp. 1031-1032
Author(s):  
Yuuko S Endoh ◽  
Ryozo Yamaoka ◽  
Nobuo Sasaki
Keyword(s):  
Detection Limit ◽  
Quantitative Determination ◽  
Chromatographic Determination ◽  
Alumina Column ◽  
Average Recovery ◽  
Diaminodiphenyl Sulfone ◽  
Alumina Column Chromatography ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A liquid chromatographic (LC) method is described for the quantitative determination of sulfamoyldapsone (2-sulfamoyl-4,4'-diaminodiphenyl sulfone) in swine muscle, liver, kidney, and fat. Sulfamoyldapsone was extracted from tissues with acetonitrile saturated with n-hexane. The extract was washed with n-hexane saturated with acetonitrile, concentrated, and cleaned up by alumina column chromatography. Sulfamoyldapsone was separated on an ODS column by using acetonitrile-methanol-water (6 + 18 + 76) and was detected at 292 nm. Overall average recovery of sulfamoyldapsone added to tissues at levels of 0.1 and 0.5 /μg/g was 93.3% ± 6.0. Detection limit was 0.02 μg/g in these tissues.

scholarly journals Distance scaling method for accurate prediction of slowly varying magnetic fields in satellite missions

2016 ◽  
Vol 5 (2) ◽  
pp. 281-288 ◽  
Author(s):  
Panagiotis P. Zacharias ◽  
Elpida G. Chatzineofytou ◽  
Sotirios T. Spantideas ◽  
Christos N. Capsalis
Keyword(s):  
Signal To Noise Ratio ◽  
Near Field ◽  
Magnetic Behavior ◽  
Field Measurements ◽  
High Signal ◽  
Signal To Noise ◽  
Scaling Method ◽  
Magnetic Signature ◽  
The Magnetic Field

Abstract. In the present work, the determination of the magnetic behavior of localized magnetic sources from near-field measurements is examined. The distance power law of the magnetic field fall-off is used in various cases to accurately predict the magnetic signature of an equipment under test (EUT) consisting of multiple alternating current (AC) magnetic sources. Therefore, parameters concerning the location of the observation points (magnetometers) are studied towards this scope. The results clearly show that these parameters are independent of the EUT's size and layout. Additionally, the techniques developed in the present study enable the placing of the magnetometers close to the EUT, thus achieving high signal-to-noise ratio (SNR). Finally, the proposed method is verified by real measurements, using a mobile phone as an EUT.

Specific determination of 3-methoxy-4-hydroxyphenylethylene glycol in urine by liquid chromatography with post-column reaction.

1988 ◽  
Vol 34 (1) ◽  
pp. 87-90 ◽  
Author(s):  
K Abe ◽  
R Konaka
Keyword(s):  
High Performance ◽  
Signal To Noise Ratio ◽  
High Performance Liquid Chromatographic ◽  
Reference Intervals ◽  
Reversed Phase ◽  
Sodium Metaperiodate ◽  
Liquid Chromatographic Method ◽  
Analytical Recovery ◽  
Liquid Chromatographic

Abstract We describe a "high-performance" liquid-chromatographic method for determining 3-methoxy-4-hydroxyphenylethylene glycol (MHPG) in human urine. MHPG is separated on a reversed-phase column with isocratic elution, oxidized with sodium metaperiodate, and its absorbance measured at 365 nm. This method shows higher specificity, less interference for MHPG than methods involving electrochemical or fluorescence detection. Post-column derivatization of MHPG with periodate yields vanillin. The detection limit (twice the signal-to-noise ratio) in urine samples was 0.08 mg/L. Mean analytical recovery was 72%. Within-assay and day-to-day CVs were 2.9% and 6.5%, respectively. Reference intervals for MHPG in 24-h urine from apparently healthy subjects were 0.85-3.24 mg/day for men and 0.63-2.20 mg/day for women. In terms of creatinine excretion, the respective reference intervals were 0.55-1.99 and 0.70-1.96 mg per gram of creatinine.

Determination of creatinine in serum and urine by a rapid liquid-chromatographic method

1990 ◽  
Vol 36 (6) ◽  
pp. 830-836 ◽  
Author(s):  
R Paroni ◽  
C Arcelloni ◽  
I Fermo ◽  
P A Bonini
Keyword(s):  
Signal To Noise Ratio ◽  
Liquid Chromatographic Method ◽  
Analytical Recovery ◽  
Internal Standardization ◽  
Assay Precision ◽  
Fuller’S Earth ◽  
Liquid Chromatographic ◽  
Specific Evaluation ◽  
Serum And Urine

Abstract We describe an HPLC ion-pair procedure for rapid and specific evaluation of creatinine in serum and urine. We used a 15 cm X 4.6 mm ODS column with a 50/50 (by vol) mixture of sodium decanesulfonic acid (10 mmol/L, pH 3.2) and methanol and measured absorbance at 236 nm. Serum (100 microL) or 30-fold-diluted urine (100 microL) was added to 400 microL of acetone. After centrifugation, the supernates (300 microL) were dried, reconstituted with the mobile phase, and injected into the HPLC. Assay precision was tested for concentrations of 10, 29, and 130 mg/L and yielded, respectively, 3.1%, 2.1%, and 1.1% for within-day CV and 2.8%, 2.1%, and 2.2% for total CV. Analytical recovery was 102 (+/- 6.7%). Linearity was demonstrated in the 0-200 mg/L range for serum and 0-3.5 g/L range for urine (r greater than or equal to 0.999). The detection limit for creatinine (signal-to-noise ratio = 3) was 0.5 mg/L. We used cimetidine for internal standardization. Correlation was good between this procedure and the Jaffé kinetic, the enzymatic (creatinine amidohydrolase), and the Fuller's earth alkaline picrate methods.

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