scholarly journals A sequential injection system for indirect spectrophotometric determination of lactic acid in yogurt and fermented mash samples

2010 ◽  
Vol 96 (1) ◽  
pp. 151-156 ◽  
Author(s):  
A.C.B. Dias ◽  
R.A.O. Silva ◽  
M.A.Z. Arruda
Keyword(s):  
Lactic Acid ◽  
Spectrophotometric Determination ◽  
Injection System ◽  
Sequential Injection

scholarly journals A Double-Line Sequential Injection System for the Spectrophotometric Determination of Copper, Iron, Manganese, and Zinc in Waters

2005 ◽  
Vol 88 (2) ◽  
pp. 639-644 ◽  
Author(s):  
Inês P A Morais ◽  
M Renata S Souto ◽  
António O S S Rangel
Keyword(s):  
Metal Ions ◽  
Spectrophotometric Determination ◽  
Absorption Spectrometry ◽  
Injection System ◽  
Sequential Injection ◽  
Double Line ◽  
Relative Standard ◽  
Iron Manganese ◽  
Determination Of Copper

Abstract A double-line sequential injection system was developed for the spectrophotometric determination of several metal ions in waters. The proposed double-line configuration was used to enable adding sample and chromogenic reagents as merging zones. The methodology was applied to the spectrophotometric determination of copper, iron, manganese, and zinc in samples of diverse origins at the range of 0.15–5.00, 0.10–10.0, 0.48–4.00, and 0.11–5.00 mg/L, respectively. Different chromogenic reagents and detection wavelengths were used. The chromogenic reagents for iron and manganese were 1,10-phenanthroline and formaldoxime, respectively. Copper and zinc were both determined using the analytical reagent zincon. Analytical characteristics of the methodology, such as manifold parameters, buffer pH, and reagent concentrations were optimized, and interference of some of the metal ions commonly present in water sample was assessed. Results of the analysis were in agreement with those obtained by atomic absorption spectrometry. Repeatability, expressed as the relative standard deviation for 10 consecutive injections of water samples, was lower than 6%. The determination rate was approximately 36/h.

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