A New Flow Injection System with Merging-Zone Technique for the Determination of Copper(II) by Neocuproine Reagent in Aqueous Solution

Abstract

A fast, simple, and high throughput sample merging-zone flow injection design was developed to determine copper(II) in aqueous solution. The procedure is based on the reduction of copper(II) to copper(I) by uric acid followed by a direct reaction with Neocuproine reagent (NC). The orange-yellow complex that forms absorb light at 454 nm. All conditions of the new flow injection unit were investigated. The analytical curve of copper(II) was linear with (r2) value of 0.9978, in the range of 0.4 to 40 mg/L with a detection limit of 0.1 mg/L and a quantification limit of 0.3 mg/L. the molar absorptivity was 1.661 × 105 L/mol cm and the recovery range was between 104.9 and 97%. The homemade acrylic valve was low-cost with zero dead volume and high repeatability (n = 7) with an RSD of 2.31%. The dispersion coefficient values were 1.8,1.62, and 1.31 for the concentrations of 5, 15, and 25 mg/L, respectively. The sample throughput was 69 h–1.

Microflow Injection System for Efficient Cu(II) Detection Across a Broad Range

“…Obviously, these LoDs are lower than this work (9 mg L -1 ) since our linear range was 34 -2000 mg•L -1 . In fact, a comparison with the literature supports this, revealing a three-orderof-magnitude difference between the LoD and the maximum concentration of the linear range in our study and the referenced works [52][53][54][55][56][57][58][59]. As regards selectivity, another parameter to compare, the previously mentioned studies showed good selectivity for determining Cu(II) [52][53][54][55][56][57][58][59].…”

“…Value Sensitivity (V L mg -1 ) 0.00078 ± 0.00002 Detection limit (mg L -1 ) 9 Quantification limit (mg L -1 ) 34 Linear range (mg L -1 ) 34 -2000 Repeatability (CV) (n=6) 0.3% -1.1% Reproducibility (CV) (n=12) 3.9% -7.4% Selectivity not interferences [52] Sample throughput (h -1 ) 7…”

“…In order to compare our system with other similar methods, in Table S3 shows the characteristics of other flow analysis methods where different reagents are shown [52][53][54][55][56][57][58][59]. The distinctive feature of our analyzer was its extensive linear response range, setting it apart from alternative automated systems.…”

“…The distinctive feature of our analyzer was its extensive linear response range, setting it apart from alternative automated systems. The maximum ranges found in the literature were 1-170 mg L -1 [53] and (0.4-40 mg L -1 ), studies which also used neocuproine [52]. Both mentioned studies had LoD of 0.1 mg L -1 .…”

Método de inyección de flujo sensible a base de neocuproina para la determinación de ácido mefenámico en soluciones acuosas y formulaciones farmacéuticas

“…Because of its selectivity for copper(I) and potent visual absorbance of the Cu(DMP) 2+ adduct, 2,9-dimethyl-1,10-phenanthroline (NC) is typically the reagent chosen for the colorimetric measurement of copper(I) (14) Water-insoluble mefenamic acid is somewhat soluble in (chloroform) and (ethers), faintly soluble in ethanol (4.6 mg/mL) and water (1:9), and more soluble in dimethylformamidee (38.5 mg/mL) (4) Mefenamic acid reduces inflammation and pain by inhibiting COX and prostaglandin synthesis since it provides cerebral and peripheral analgesia. Its nonselective COX inhibitors inhibit both COX-1 and COX-2 enzymes (5) Mefenamic Acid (MFA) operates in the same way as other nonsteroidal anti-inflammatory medicines by which blocking the enzymatic prostaglandin synthase (6) There are several known and reported analytical methods for measuring MEF acid in biological and pharmacological products (7) Spectrophotometry (8) Gas Chromatography (9) Extraction method of Micro-electrodriven Membranes in 2 Phases (10) capillary electrophoresis with two channels (11) RP-HPLC (12) Fluorometric method (13) Hyphenated Tech-niques (14) Electrospray Ionization Mass Spectrometry (15) Turbidity Measurement (16) flow injection method (17) MEF is determined by different flow injection technique, it has been estimated in pharmaceuticals by flow-injection (18) and estimation of Mefenamic Acid in Aqueous Solutions Using Reverse -Continuous Flow Injection Analysis (6) determination of MEF in pharmaceuticals formulation by flow-injection Fluorometry (21). However, in recent years there has been a growing interest in the use of Neocuproine (2,9-dimethyl-1,10-phenanthroline) as a complexing agent in analytical chemistry.…”