Sorption detection

Integrated sorption-detection units are based on the placement of an inert or active support in the flow cell of a nondestructive spectroscopic detector where the analytes or their reaction products are retained temporarily for sensing immediately after their elution. The equipment required to develop this type of sorption methodology is very simple and closely resembles that used in ordinary flow injection analysis (FIA) manifolds. The only difference lies in the replacement of the packed reactor located in the transport-reaction zone with a packed flow cell (usually photometric or fluorimetric) situated in the detector. 

Analytical derivatization reactions can be implemented in integrated sorption-detection systems by using reagents immobilized (bonded or ab-... 

Two techniques for sorption-spectroscopic determination of ascorbic acid have been proposed. The first one is the recovery by silica modified with tetradecyl ammonium nitrate of blue form of molibdophosphoric HPA in the presence of vitamin C. And the second one is the interaction between the ascorbic acid in solution and immobilized on silica ion associate of molibdophosphoric acid with lucigenine. The detection limits of vitamin C are 0.07 and 2.6 mg respectively. The techniques were successfully applied to the determination of ascorbic acid in fmit juices. 

PSS-SG composite film was tested for sorption of heme proteins hemoglobin (Hb) and myoglobin (Mb). The peroxidaze activity of adsorbed proteins were studied and evaluated by optical and voltammetric methods. Mb-PSS-SG film on PG electrode was shown to be perspective for detection of dissolved oxygen and hydrogen peroxide by voltammetry with linear calibration in the range 2-30 p.M, and detection limit -1.5 p.M. Obtained composite films can be modified by different types of biological active compounds which is important for the development of sensitive elements of biosensors. 

In our investigations, we also detected the sorption of isoPO from potato, Arabidopsis and wheat, by calcium pectate. Moreover, we observed the binding with calcium pectate of potato PO from the fraction of proteins ionically bound with cell walls. It is likely that the ability of some PO isoforms to bind with pectin ensures the spatial proximity of these enzymes to the sites of the initiation of lignin synthesis and that these "pectin-specific" isoforms take part in this process. 

ECD Electron capture detection Ko, Kqc Soil sorption coefficients... 

The main characteristic features of HPTLC (use of fine particle layers for fast separations, sorbents with a wide range of sorption properties, high degree of automation for sample application, development and detection) are the exact opposite of conventional TLC. Expectations in terms of performance, ease of use and quantitative information from the two approaches to TLC are truly opposite [419], Modern TLC faces an uncertain future while conventional TLC is likely to survive as a general laboratory tool. 

Regarding submerged plants, sorption of Cu(II) by Myriophyllum spicatum L. (Eurasian water milfoil) has been shown to be fast and fits isotherm models such as Langmuir, Temkin, and Redlich-Peterson. The maximum sorption capacity (c/lll l j ) of copper onto M. spicatum L. was 10.80 mg/g, while the overall sorption process was best described by the pseudo-second-order equation.115 Likewise, Hydrilla verticillata has been described as an excellent biosorbent for Cd(II). In batch conditions, the qmsx calculated was 15.0 mg/g. Additionally, II. verticillata biomass was capable of decreasing Cd(II) concentration from 10 to a value below the detection limit of 0.02 mg/L in continuous flow studies (fixed-bed column). It was also found that the Zn ions affected Cd(II) biosorption.116... 

The sPS has been exploited as sensitive material for fiber optic chemical sensors based on reflectance measurements and aimed to detection of chloroform and toluene in water and air environments48 50. The refractive index of sPS thin films is estimated to be about 1.578. The effect of the analyte sorption in the crystalline domain was modeled as an increase in the material density, which in turn leads to an increase in the refractive index according to the Lorentz-Lorenz law ... 

Are the concentrations of these pesticides being attenuated to below troublesome or detectable levels in passage through the unsaturated zone, and is this primarily due to sorption or degradation ... 

The eluate from the FBBR inhibited with formaldehyde shows an initial rapid loss of LAS followed by a steady loss until day 7, after which the concentration of LAS remains stable at about half the value in the reservoir (Fig. 5.1.7). No degradative products were detected in this experiment, and therefore the loss can be attributed to sorption. However, it is important to note that precipitation of magnesium and calcium salts can also contribute to the loss of the anionic surfactant [94]. 

Despite these reservations, environmental distribution values may be considered valid for the sorption process, to a first approximation. On this basis, it can be concluded that detected environmental partition coefficients show the clear affinity of surfactants to particulate material. The affinity is higher for cationic surfactants than for other surfactants, as shown by the high partition coefficient values (Table 5.4.1). Partition coefficients are also higher for the water column than for sediments (Table 5.4.1), and it is difficult to offer an explanation for this, bearing in mind the many factors affecting the partition coefficient in both natural water and sediment. 

Particulate matter concentration, organic content and granulometry For the different types of surfactant, the effect of solids concentration on sorption is unclear. While some studies have shown that the concentration of solids has no effect on the extent of sorption [19,36], in others, it has been detected that the partition coefficient decreases with particle concentration [17,27,37,38]. 

The residues of LAS and ABS detected in the three investigated water streams entering Laguna de Bay could be further reduced by dilution, or biochemical degradation (mainly for LAS). Removal of the surfactants through sorption and precipitation had also been taken into account. This elimination route was particularly important for ABS since many of its derivatives were rather insoluble [26]. 

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