A highly sensitive and rapid spectrophotometric method for the determination of molybdenum at nano-trace levels in some real, environmental, biological, food and soil samples using salicylaldehyde-benzoylhydrazone

Abstract

A very simple, sensitive and highly selective non-extractive new spectrophotometric method has been developed for the determination of molybdenum at nano-trace levels using salicylaldehyde-benzoylhydrazone (Sal-BH). The method is based on the reaction of non-absorbent Sal-BH in a slightly acidic solution (0.0025-0.0075 M H2S04) with molybdenum (VI) to give a light yellowish chelate, which has an absorption maximum at 440 nm. The reaction is instantaneous and absorbance remains stable for over 24 h. The average molar absorption coefficient and Sandell’s sensitivity were found to be 4.32×105 L/mol.cm and 5 ng/cm2 of molybdenum, respectively. Linear calibration graphs were obtained for 0.01-60.00 mg/L of molybdenum having detection limit of 1 µg/L and RSD 0.0-2.0 %. The stoichiometric composition of the chelate is 1:1 (Mo:Sal-BH). A large excess of over 60 cations, anions and some common complexing agents (such as chloride, azide, tartrate, EDTA, SCN- etc.) do not interfere in the determination. The method was successfully used in the determination of molybdenum in several Certified Reference Materials (Alloys, steels, water, hair and bovine liver) as well as in some environmental waters (Potable and polluted), biological samples (Human blood, urine, nails, hair, food and vegetables), soil samples, and solutions containing both molybdenum(VI) and molybdenum(V) as well as complex synthetic mixtures. The results of the proposed method for assessing biological, food and vegetables samples were found to be in excellent agreement with those obtained by ICP-OES and AAS. The method has high precision and accuracy (s = ±0.01 for 0.5 mg/L).

Development of a new highly sensitive and selective spectrophotometric method for the determination of selenium at nano-trace levels in various complex matrices using salicylaldehyde-orthoaminophenol

“…Therefore, this method will be successfully applied to the routine monitoring of trace and ultra-trace amounts of selenium in real, environmental, biological, soil, food and pharmaceutical samples. It is a new method needs neither heating nor extraction to organic phase, works satisfactorily and could be an alternative method for the rapid determination of selenium in a wide variety of sample solutions and found superior to spectrophotometric methods described in different literature [73][74][75][76][77][78][79][80][81][82].…”

A Highly Selective and Simple Spectrophotometric Method for the Determination of Zinc at Nano-trace Levels in Some Environmental, Biological, Food, and Pharmaceutical Samples Using 2-hydroxynaphthaldehydebenzoylhydrazone

“…The vegetable and food samples were digested using a method recommended by Stahr [27]. The digested sample was measured using a volumetric flask and the zinc content was determined as described using tartrate as a masking agent [28]. The Zn contents in the vegetable and food samples were compared with the conventional atomic absorption spectroscopy and the results were in excellent agreement ( Table 9).…”

A highly sensitive and selective spectrophotometric method for the determination of vanadium at nanotrace levels in some environmental, biological, soil, food, and pharmaceutical samples using salicylaldehyde-benzoylhydrazone

“…In this study, we developed a very simple method for the quantification of vanadium using a spectrophotometer. Salicylaldehyde-benzoylhydrazone (Sal-BH) has been reported as a spectrophotometric reagent for copper(II) [14] and molybdenum(VI) [15] but has not previously been used for vanadium. This paper reports its use in a very sensitive, highly specific spectrophotometric method for the trace determination of vanadium.…”