• Archives of Pharmacal Research
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• v.4 no.1
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• pp.9-17
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• 1981

A simple, accurate and specific NMR procedure is described for the determination of amplicilin and cloxacillin mixtures in injection dosage form and capsules. The solvent was dimethysulfoxde $d_{6}$ and maleic acid was the internal standard. By integrating the peak at 2.68 ppm and 4.57 ppm, cloxacillin and ampicillin could be determined respectively. The relative proton ratio of ampicillin trihydrate and cloxacillin were 1.038 and 0.950. The coefficents of variation of amplicillin trihydrate and cloxacillin in a few commerical preparation were 1.55 % (n =9), 2.69 % (n =15).

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.45 no.1
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• pp.27-34
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• 2013

Quantitative analysis of 5-hydroxymethylfufural (5-HMF) conversion from fructose by dehydration and rearrangement was investigated by $^1H$-NMR spectroscopic method. Fructose was converted to 5-HMF in dimethylsulfoxide (DMSO)-$d^6$ or acidic deuterium hydroxide at controlled reaction temperature and time. With addition of internal standards (biphenyl for DMSO-$d^6$ solvent, and 2,5-dihydroxybenzoic acid for deuterium oxide solvent), conversion from fructose to 5-HMF was analyzed by $^1H$-NMR spectroscopy. Quantitative analysis was run by comparison with peak area integration between of 5-HMF and internal standard. In DMSO solvent, 5-HMF was stable end product but part of 5-HMF was converted to formic and levulinic acid at acidic aqueous medium.

• YAKHAK HOEJI
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• v.28 no.5
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• pp.287-291
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• 1984

A rapid and accurate NMR procedure for the analysis of a mixture of sulfametrol, sulfalene and sulfameter in $CDCl_3$ and $dimethylsulfoxide-d_6$ was developed. Thioacetamide was used as an internal standard. The signals chosen for the analysis were a singlet of 4.03ppm due to the methoxyl group of sulfametrol, a singlet of 3.98ppm due to the methoxyl group of sulfalene and a singlet of 3.83ppm due to the methoxyl group of sulfameter. The quantification of the characteristic peak was done by the integration method and the peak height method. The variation coefficient of sulfametrol, sulfalene and sulfameter were 1.7(n=6), 1.7(n=6) and 1.4%(n=6), respectively in the peak height method and 8.9(n=6), 9.4(n=6) and 7.0(n=6), respectively in the integration method.