Nitrogen Cycling in Natural Waters using In Situ, Reagentless UV Spectrophotometry with Simultaneous Determination of Nitrate and Nitrite

2007 ◽  
Vol 41 (24) ◽  
pp. 8420-8425 ◽  
Author(s):  
Richard C. Sandford ◽  
Alexandra Exenberger ◽  
Paul J. Worsfold
Keyword(s):  
Nitrogen Cycling ◽  
Simultaneous Determination ◽  
Natural Waters ◽  
Uv Spectrophotometry ◽  
Nitrate And Nitrite

scholarly journals Simultaneous Determination of Amlodipine and Valsartan

2011 ◽  
Vol 6 ◽  
pp. ACI.S7282 ◽  
Author(s):  
Nashwah Gadallah Mohamed
Keyword(s):  
Absorption Spectrum ◽  
Simultaneous Determination ◽  
Zero Order ◽  
Uv Spectrophotometry ◽  
Ratio Spectrum ◽  
First Derivative ◽  
Bulk Powder ◽  
Overlapped Peaks ◽  
Third Derivative

A spectrophotometric method was developed for simultaneous determination of amlodipine (Aml) and valsartan (Val) without previous separation. In this method amlodipine in methanolic solution was determined using zero order UV spectrophotometry by measuring its absorbency at 360.5 nm without any interference from valsartan. Valsartan spectrum in zero order is totally overlapped with that of amlodipine. First, second and third derivative could not resolve the overlapped peaks. The first derivative of the ratio spectra technique was applied for the measurement of valsartan. The ratio spectrum was obtained by dividing the absorption spectrum of the mixture by that of amlodipine, so that the concentration of valsartan could be determined from the first derivative of the ratio spectrum at 290 nm. Quantification limits of amlodipine and valsartan were 10-80 μg/ml and 20-180 μg/ml respectively. The method was successfully applied for the quantitative determination of both drugs in bulk powder and pharmaceutical formulation.

D-optimal design for electrochemical simultaneous determination of bentazon and fenamiphos in natural waters

2021 ◽  
pp. 1-14
Author(s):  
Lucia Codognoto ◽  
Thays S. Lima ◽  
Fábio R. Simões ◽  
Heron D. T. Da Silva ◽  
Eliana M. A. Valle
Keyword(s):  
Optimal Design ◽  
Simultaneous Determination ◽  
Natural Waters
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