Solid‐phase extraction using octadecyl‐bonded silica modified with photosynthetic pigments from Spinacia oleracea L. for the preconcentration of lead(II) ions from aqueous samples

Abstract

Spinacia oleracea L. extract was immobilized on an octadecyl-bonded silica surface to produce a new sorbent for the solid-phase extraction of trace amounts of metal ions from aqueous neutral samples. A measurement of the metal content has been performed by using graphite furnace atomic absorption spectroscopy. The affinity of the investigated bivalent metal cations for the modified sorbent are in the order: Pb(II) > Cu(II) > Ni(II) > Zn(II) ≈ Cd(II) ≈ Co(II). The quantum-chemically calculated chlorophyll-a-metal ion binding energies were consistent with the measured affinities of the corresponding metal ions to the investigated sorbent. The maximum sorption capacity obtained for Pb(II) was equal to 1.44 μmol/g. The value of lead uptake was significantly higher in comparison to the one reported for other sorbents and biosorbents. Immobilized chlorophyll a is responsible for a chelation process with stoichiometry 1:1 owing to the porphyrin rings, which was confirmed by the quantitative analysis performed by reversed-phase high-performance liquid chromatography with diode array detection. The Toth adsorption isotherm model was applicable to the description of the adsorption process of either chlorophyll a or Pb(II). The structural analysis of sorbent was done using Fourier-transform Raman spectroscopy and scanning electron microscopy with an energy dispersive X-ray detector.

Controllable preparation and performance of bio-based poly(lactic acid-iminodiacetic acid) as sustained-release Pb2+ chelating agent

“…From the results shown in Figure S12 , we come to know that with the increase of n (LA): n (IDA), the Pb 2+ chelating capacity of P(LA- co -IDA)s is gradually decreased from 1.80 mg·g −1 of IDA8 to 0.33 mg·g −1 of IDA128. The datum is similar to ( Tahtat et al., 2017 ; El-Ashgar et al., 2017 ) or higher than ( Liu et al., 2020 ; Blicharska et al., 2018 ) that of the reported polymeric (or M w over 1,200 Da) Pb 2+ chelators using IDA or other substances as functional groups. Importantly, this level of chelating capacity is suitable for a potential biomedical chelating agent as a treatment drug for chelating and removing lead ions in vivo because the threshold of lead poisoning that requires treatment is 10 μg·dL −1 ( Balasubramanian et al., 2020 ), and the corresponding dosage of small molecule chelating drugs is as low as 30 mg·kg −1 body weight per day ( Safi et al., 2019 ).…”

Ethylenediaminetetraacetate functionalized ordered Santa Barbara Amorphous‐15 mesoporous silica as an effective adsorbent for preconcentration of some heavy metals followed by inductively coupled plasma atomic emission spectrometry

“…Various sample pretreatment methods such as cloud point extraction (CPE) [4], co-precipitation [11], liquidliquid extraction (LLE) [6], and solid-phase extraction (SPE) [7,12] have been used to preconcentrate metal ions and eliminate matrix effects. Some advantages of the SPE technique such as the short extraction time, low consumption of organic solvents, and adsorbents have resulted in the wide applications of this method for extraction of various organic and inorganic pollutants [13].…”