Polymeric cartridge

C. Aguilar, I. Feirer, R Bonnll, R. M. Marce and D. Barcelo, Monitoring of pesticides in river water based on samples previously stored in polymeric cartridges followed by on-line solid-phase extraction-liquid cliromatography-diode array detection and confirmation by atmospheric pressure chemical ionization mass spectrometry . Anal. Chim. Acta 386 237-248 (1999). 

Ferrer and Barcelo [131] used online solid-phase-liquid chromatography mass spectrometry for the simultanous determination of organotin antifouling herbicides in marine water. The solid-phase extraction was carried out on polymeric cartridges after percolation of 100 ml of the seawater sample, and... 

SPEC was essentially able to market their Zr02-based ultrafiltration membranes to an already existing market in the sense that these membranes replaced polymeric UF membranes in a number of applications. They also developed a certain number of new applications. For Ceraver, the situation was different. When the Membralox membranes were first developed, microfiltration was performed exclusively with dead-end polymeric cartridge filters. In parallel to the development of inorganic MF membranes, Ceraver initiated the development of cross-flow MF with backflushing as a new industrial process. 

LC/MS/MS is an important technique for the analysis of free metabolites and covalent adducts of sulfur mustard in urine and blood. In the case of TDG and TDGO, LC/MS has not yet been able to achieve the LODs obtainable with GC/MS after derivatization. LC/MS/MS has, however, been used successfully to analyze the metabolites (20, 21) derived from an initial reaction of sulfur mustard with glutathione (see Chapter 16). The two metabolites (20), derived from the 3-lyase pathway, can be isolated from urine by SPE on a hydroxylated polystyrene-divinylbenzene polymeric cartridge. Using a sensitive triple sector quadrupole LC/MS/MS system, detection limits of O.lng/ml have been achieved using positive ESI and MRM (56). This provides a useful alternative to GC/MS/MS, which requires reduction of the sulfoxide functions with titanium trichloride. An LC/MS/MS method (detection limit lng/ml) has been developed for the analysis of the hisf N - ace ly I cysteine) metabolite (21) in urine (57). Concentration from acidified urine was achieved on... 

An alternative to GC/MS/MS of the reduced product (10) is direct FC/ESI/MS/MS of (2) and (3). The analytes can be isolated from urine by SPE on a hydroxylated polystyrene-divinylbenzene (PS-DVB) polymeric cartridge. Using a sensitive triple sector quadrupole LC/MS/MS system, detection limits of O.lng/ml have been achieved using positive ESI and MRM (30). 

Sorbents Cig on silica and polymeric sorbents (Oasis and LiChrolut EN), the best results being obtained with the 18 styrene-DVB cartridge and when the elution was performed with methanol and ethyl acetate Sorbent polymeric cartridges (PLRP-s)... 

Several clean-up methods have incorporated the use of additional liquid-liquid steps with solvents such as chloroform and ethyl acetate. Alternatively, some authors have turned to ultrafiltration for further purification.Additionally, hexane is extensively used in several methods to further remove non-polar matrix components such as fats and lipids. By far, the most popular clean-up technique reported in the literature is the use of solid phase extraction (SPE). Some common phases reported include CIS cartridges such as SepPak C18, Strata Chromobond C18, " and Mega Bond Elut C18. The use of silica, alumina, and Extralut " " has also been reported, as well as polymeric cartridges such as Oasis HLB. The latter phase has been reported as the basis of an on-line clean-up procedure. Because of their amphoteric nature, as both weak acids and weak bases, the sulfonamides also lend themselves to analysis by ion exchange. Cationic SPE has been reported by several authors.On the basis of the same principles, anionic exchange has also been used. " ... 

Stability studies of SPE-adsorbed anihdes and N-substituted amines (bentazone, molinate and metolachlor) were performed by means of APCI-LC-MS. From river water samples containing the pesticides and their degradation products, the pesticides had been extracted prior to APCI-LC-MS [320]. The SPE adsorbed compounds were stored on SPE cartridges (styrene-divinylbenzene) for up to 3 months at ambient temperature, +A °C and -20 °C. After 3 month storage at -20 °C on the polymeric cartridges recoveries were > 90% [320]. 

Results and discussion Representative examples of extraction efficiencies obtained using four different solid phase extraction cartridges (polymeric, C18, and two ion exchange) as well as two pH values for the most effective polymeric cartridge (Oasis HLB) are shown in Figure 4.3. Contaminants were recovered effectively from river water as well as from the influent and effluent flows of a water treatment plant. Recoveries were in the 60-102% (surface water) and 50-116% (wastewater) range, with a few compounds in the 35-50% range. Calibration curves for all compounds had r values of >0.99. 

Promising results were obtained by Ali et al. [65], who used C18 SPE cartridges, which achieved good recoveries (>95%) for the extraction of flavonoids from apple juice. On the other hand, anthocyanidins can be extracted from tomato using polymeric cartridges, utilizing a mixture of methanohformic acid (95 5) [47] as elution solvent. 

Figure 2.19 Forms of cartridge filters vary widely these examples show pleated metallic and polymeric cartridges towards the left hand side of the photograph, and wound cartridges towards the right (Amafilter).

Thus, protein precipitation followed by ultrafiltration or SPE with polymeric cartridges (e.g., HLB), "dilute-and-shoot," or QuEChERS methodologies [17,20] are being used. 

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