Potential pitfall in the determination of free [Mg2+] by31P NMR when using the β/α-ATP peak height ratio method

1999 ◽  
Vol 9 (1-2) ◽  
pp. 1-4
Author(s):  
Stefan Widmaier ◽  
Wulf-Ingo Jung ◽  
Günther J. Dietze ◽  
Otto Lutz
Keyword(s):  
Peak Height ◽  
Ratio Method ◽  
Peak Height Ratio ◽  
Height Ratio ◽  
Potential Pitfall

Determination of the Composition of TiNx and TiBxNy Films by AES

1995 ◽  
Vol 50 (7) ◽  
pp. 624-630 ◽  
Author(s):  
M. A. Baker ◽  
J. Haupt ◽  
W. Gissler
Keyword(s):  
Complex Shape ◽  
Peak Height ◽  
Main Peak ◽  
Peak Height Ratio ◽  
Height Ratio ◽  
Peak Intensity Ratio ◽  
Negative Peak ◽  
Peak Intensity ◽  
Second Peak

For the determination of x and y of TiNx and TiBxNy coatings two Auger methods are presented, one circumventing and the other minimising the difficulties arising from the overlap of the KL23L23 and L3M23M23 peaks of N and Ti, respectively. The first method, developed for TiNx coatings, is based on the L3M23M45 valence band peak of Ti which develops a distinct second peak on nitridation, 3.9 eV below the main peak, labelled the L3M23Hybrid peak. After a simple Shirley background correction, a linear dependence of the L3M23Hybrid/L3M23M45 peak height ratio on the N/Ti ratio was found. This allows the determination of the N content of a TiNx compound. For TiBxNy coatings, a more complex shape of the L3M23M45 peak is obtained due to the presence of more than one phase, rendering this peak unusable for quantification. Therefore the N/Ti ratio is obtained from the L3M23M23/L3M23M4, peak intensity ratio for Ti. To minimise influences of the fine structure and improve the accuracy of the method, the negative peak excursions were artificially broadened. The N/Ti ratio so obtained is used in combination with the B concentration determined from the KL23L23 peak of B to yield the Ti-B-N composition.

scholarly journals Liquid Chromatographic Method for Determination of Nisoldipine from Pharmaceutical Samples

2010 ◽  
Vol 7 (3) ◽  
pp. 751-756 ◽  
Author(s):  
Amit Gupta ◽  
Ram S. Gaud ◽  
S. Ganga
Keyword(s):  
High Performance ◽  
Chromatographic Method ◽  
Peak Height ◽  
Peak Height Ratio ◽  
Height Ratio ◽  
Liquid Chromatographic Method ◽  
Aluminum Plates ◽  
Tablet Dosage ◽  
Liquid Chromatographic

A simple and specific high performance thin layer chromatographic method was developed and validated for the determination of nisoldipine from tablet dosage form. The method was carried out at 320 nm after extraction of drug in methanol. The method uses aluminum plates pre-coated with silica gel 60F-254 as stationary phase and cyclohexane-ethyl acetate-toluene (3:3:4, v/v/v) as mobile phase. Linearity was established over a range of 400-2400 ng per zone. Both peak area ratio and peak height ratio showed acceptable correlation coefficienti.e.more than 0.99. However we used peak area for validation purpose. Intra-day and inter-day precision was determined and found to have less than 6.0 % RSD.

Quantitative determination of titanium tetrachloride and dichloromethane by Raman spectroscopy using carbon disulfide as an internal standard

2020 ◽  
Vol 12 (7) ◽  
pp. 988-995
Author(s):  
Xiaoyan Xiang ◽  
Xianda He ◽  
Wentang Xia ◽  
Jianguo Yin ◽  
Xiaoli Yuan ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Quantitative Analysis ◽  
Quantitative Determination ◽  
Carbon Disulfide ◽  
Titanium Tetrachloride ◽  
Internal Standard ◽  
Peak Height ◽  
Peak Height Ratio ◽  
Height Ratio

Raman spectroscopy with an internal standard and peak height ratio was applied for the quantitative analysis of dichloromethane and titanium tetrachloride.

Correlation between Physico-Mechanical Properties of NR-BR Blends in Tire Tread Formulation with their Thermal Behaviors

2008 ◽  
Vol 81 (2) ◽  
pp. 297-317 ◽  
Author(s):  
Saeed Taghvaei-Ganjali ◽  
Fereshteh Motiee ◽  
Farsa Fotoohi
Keyword(s):  
Mechanical Properties ◽  
Thermal Analysis ◽  
Peak Height ◽  
Peak Height Ratio ◽  
Butadiene Rubber ◽  
Height Ratio ◽  
Thermal Behaviors ◽  
Degradation Temperature ◽  
Rubber Compounds ◽  
Successful Technique

Abstract Thermal analysis provides a successful technique for the characterization and identification of rubber compounds. In this study, TGA (thermogravimetric analysis) and DTG (TGA derivative) profiles are used to predict and define the physico-mechanical properties of natural rubber — butadiene rubber (NR / BR) blends, using their thermal behaviors. DTG curves of vulcanizate showed that the initial degradation temperature of NR is lower than BR. According to TGA-DTG profiles we have demonstrated two useful factors, ΔTmax (Tmax BR100−Tmax BRX) and peak height ratio of NR-BR blends which are correlated with physico-mechanical properties of blends.

"High-pressure" liquid chromatography of sulfisoxazole and N4-acetylsulfisoxazole in body fluids.

1980 ◽  
Vol 26 (1) ◽  
pp. 51-54
Author(s):  
D Jung ◽  
S Oie
Keyword(s):  
Internal Standard ◽  
Peak Height ◽  
Absolute Methanol ◽  
Peak Height Ratio ◽  
Pharmacokinetic Studies ◽  
Height Ratio ◽  
Calculated Concentration ◽  
Supernatant Solution ◽  
Clinical Drug ◽  
Clear Supernatant

Abstract We describe a simple, rapid chromatographic method for separating and quantitatively determining sulfisoxazole and its N4-acetyl metabolite in plasma and urine. A 100-micro L sample of plasma or urine is combined with 200 micro L of a solution containing 12 mg/L of the internal standard, N4-acetylsulfamethoxazole, in absolute methanol and centrifuged to obtain a clear supernatant solution. This solution is then eluted through a 10-micron microparticulate column with a mobile phase of 32/68 (by vol) methanol/sodium acetate buffer (0.01 mol/L, pH 4.7), at a flow rate of 1.2 mL/min. The eluted sompounds are detected by their absorption at 254 nm. We calculated concentration from the peak-height ratios of sulfisoxazole or N4-acetylsulfisoxazole to N4-acetylsulfamethoxazole. The peak-height ratio was linear with concentration in the range 0.05--200 mg/L for both drug and metabolite in plasma and urine. Because this assay can be completed within 30 min of obtaining a blood or urine sample, it should be a valuable tool in clinical drug monitoring and pharmacokinetic studies.

Micro-analysis for quinidine in serum by thin-layer chromatography followed by fluorescence densitometry.

1983 ◽  
Vol 29 (12) ◽  
pp. 2100-2102 ◽  
Author(s):  
M Kelner ◽  
D N Bailey
Keyword(s):  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Large Scale ◽  
Internal Standard ◽  
Peak Height ◽  
Peak Height Ratio ◽  
Height Ratio ◽  
Coefficients Of Variation ◽  
Micro Analysis ◽  
Layer Chromatography

Abstract We report a thin-layer-chromatographic micro-analysis for quinidine in serum, with detection by fluorescence densitometry. Quinidine is extracted from 20 microL of serum at pH 13 into 3 mL of hexane/acetone solution (80/20 by vol) containing N-(1-naphthyl)ethylenediamine as internal standard. The extract is concentrated and applied to silica-gel-impregnated plates for conventional thin-layer chromatography. Quinidine is identified from its RF value and quantified from the peak-height ratio between quinidine and the internal standard, relative to that of simultaneously extracted serum standards. The proposed assay is sensitive (to 0.2 mg/L), specific for unmetabolized quinidine, precise (between-run coefficients of variation less than 6%), and readily adaptable to large-scale "batch" analysis. Peak-height ratio is linearly related to concentration to at least 20 mg/L. Quinidine concentrations in the serum of patients, as measured by the proposed method (x) and by a traditional double-extraction spectrofluorometric assay (y), were related as follows: y = 0.994x + 0.276 (r = 0.989, n = 20).

A simplified and rapid test for acetylator phenotyping by use of the peak height ratio of two urinary caffeine metabolites.

1989 ◽  
Vol 35 (5) ◽  
pp. 848-851 ◽  
Author(s):  
A el-Yazigi ◽  
K Chaleby ◽  
C R Martin
Keyword(s):  
Rapid Test ◽  
Acetylator Phenotype ◽  
Peak Height ◽  
Slow Acetylators ◽  
Peak Height Ratio ◽  
Saudi Population ◽  
Height Ratio ◽  
Liquid Chromatographic

Abstract We describe a simplified liquid-chromatographic test in which acetylator phenotype is determined by measuring the peak height ratio of two urinary caffeine metabolites, 5-acetylamino-6-formylamino-3-methyluracil and 1-methylxanthine. We applied this test to determine the acetylator phenotypes of 52 subjects who regularly drink coffee, tea, or caffeinated beverages. Also, we determined the acetylator phenotypes of these subjects according to a well-established sulfasalazine test, which yielded identical results. We established the reproducibility of the described test by determining the acetylator phenotypes of 10 additional subjects on two different days separated by a period of two to five weeks. Of the 52 subjects examined by both tests, 40 (76.9%) were classified as slow acetylators, which agrees well with the percentage reported elsewhere for 297 similar subjects from the Saudi population.

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