Development of a Disposable Pipette Extraction Method Using Coffee Silverskin as an Adsorbent for Chromium Determination in Wastewater Samples by Solid Phase Extraction

A procedure using disposable pipette tips adapted for solid-phase extraction, known as DPX‑SPE, was used as an alternative way for the chromium determination in wastewater samples. DPX-SPE consists of a device which allows a dynamic contact between the sample and the solidphase. A residue obtained from the processing of coffee beans, denominate coffee silverskin, was used as a new adsorbent. Characterization techniques revealed properties of lignocellulosic materials with potential application for chromium adsorption. The parameters including adsorbent mass (25.00 mg), elution solvent (0.1 mol L−1 HCl, 200 μL) and pH (2.0) were optimized. Thus, 1.00 mL of deionized water for conditioning, 4.00 mL of sample, 2 extraction cycles and 1 elution cycle were the employed conditions. Enrichment factor of 12, limit of detection of 6.00 μg L−1 and relative standard deviation (RSD) 1.3% (n = 3) were obtained. The method proved to be fast, cheap, environmentally friendly, and simple, providing good recoveries (104-113%), and it was satisfactorily applied in real samples.

Deep eutectic solvent decomposition-based microextraction for chromium determination in aqueous environments by atomic absorption spectrometry with electrothermal atomization

A sensitive, rapid, and simple procedure for the determination of traces of chromium species in natural and waste waters after microextraction using quasi-hydrophobic deep eutectic solvent based on tetrabutylammonium bromide...

Recent Advances in Electrochemical Monitoring of Chromium

The extensive use of chromium by several industries conducts to the discharge of an immense quantity of its various forms in the environment which affects drastically the ecological and biological lives especially in the case of hexavalent chromium. Electrochemical sensors and biosensors are useful devices for chromium determination. In the last five years, several sensors based on the modification of electrode surface by different nanomaterials (fluorine tin oxide, titanium dioxide, carbon nanomaterials, metallic nanoparticles and nanocomposite) and biosensors with different biorecognition elements (microbial fuel cell, bacteria, enzyme, DNA) were employed for chromium monitoring. Herein, recent advances related to the use of electrochemical approaches for measurement of trivalent and hexavalent chromium from 2015 to 2020 are reported. A discussion of both chromium species detections and speciation studies is provided.

Titanium and Chromium Determination in Feedstuffs Using ICP-AES Technique

The present study represents the determination of Ti and Cr in dry animal feeds using wet acid digestion and inductively coupled plasma–atomic emission spectrometry (ICP-AES), in order to use these metals as digestibility markers. A radiofrequency power of 1350 W and a nebulizer argon flow of 0.8 L/min was selected. The limits of detection were between 11.4 and 16.1 μg/g for titanium and between 10.7 and 38.2 μg/g for chromium. The recovery values for the aqueous solutions were 89.5–103.9% (titanium) and 85.3–104.2% (chromium), with relative standard deviations (RSD%) under 2.1% and standard errors under 2.32%, demonstrating that the method offered good accuracy and repeatability. Six different samples of commercially available feedstuffs (two cat foods, two dog foods, and two poultry foods) were analyzed and the levels of investigated metals were found to be in the ranges of 0.10 g/kg and <LOD for chromium and titanium, respectively (dog foods); 0.10–0.18 g/kg, 0.70 g/kg for chromium and titanium, respectively (cat foods); and 0.07 g/kg, 0.82–1.35 g/kg for chromium and titanium, respectively (poultry foods).

An Improved Ion Chromatographic Method for Fast and Sensitive Determination of Hexavalent Chromium and Total Chromium Using Conductivity Detection

Chromium exists in its two stable oxidation states including trivalent chromium (Cr (III)) and hexavalent chromium (Cr (VI)) in natural waters. Chromium is an essential micronutrient in the trivalent form; however, the hexavalent form of chromium is considered to be a carcinogen. It is important to determine the chromium content along with speciation. There are a number of methods available for chromium determination. Speciation of chromium is essential to know the exact composition of chromium. Ion exchange chromatography is one of the techniques used to determine Cr (VI). The proposed method can be used to perform the speciation of Cr (III) and Cr (VI). It is a two-step process: first Cr (VI) is determined, followed by total chromium determination by treating the sample with potassium permanganate solution to oxidize the Cr (III) present in the sample to Cr (VI) and determining it as Cr (VI). Conductivity detector is used for the detection. Addition of potassium permanganate solution to the ground water samples for oxidizing the Cr (III) to Cr (VI) is the newly adopted sample preparation technique. The effect of potassium permanganate oxidation is studied in detail in the proposed method. This method can be used for chromium speciation in river water and ground water samples.