Sequential injection lab-on-valve

Long, X., M. Miro, R. Jensen, and E.H. Hansen. 2006. Highly selective micro-sequential injection lab-on-valve (pSI-LOV) method for the determination of ultra-trace concentrations of nickel in saline matrices using detection by electrothermal atomic absorption spectrometry. Anal. Bioanal. Chem. 386 739-748. 

In flow-based analytical procedures where the chemical reactions involved and/or the steps of analyte separation/concentration are relatively slow, the analytical signal can be attenuated by reducing the mean available time for the development of these physico-chemical processes. From a practical point of view, the result is equivalent to in-line analyte dilution. This possibility has been exploited in the spectrophotometric determination of hydrogen peroxide in contact lens care solutions using a sequential injection lab-on-valve system [60]. In view of the high sensitivity of the reaction between the analyte and 2,2,-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) in the presence of the enzyme... 

Hydrogen peroxide Lens care solutions Dialysis UV-Vis Up to 342 mg L 1 Sequential injection lab-on-valve system low dialysis efficiency (1.25 %) to promote in-line dilution, thus sensitivity reduction enzymatic assay [60]... 

S.S.M.P. Vidigal, I.V. Toth, A.O.S.S. Rangel, Sequential injection lab-on-valve system for the on-line monitoring of hydrogen peroxide in lens care solutions, Microchem. J. 91 (2009) 197. 

Miro M, Jonczyk S, Wang J and Hansen EH (2003) Exploiting the bead-injection approach in the integrated sequential injection lab-on-valve format using hydrophobic packing materials for on-line matrix removal and preconcentration of trace levels of cadmium in environmental and biological samples via formation of non-charged chelates prior to ETAAS detection. J. Anal Atom Spectrom 18 BOOB. 

Wang J-H and Hansen EH (2003) Sequential injection lab-on-valve the third generation of flow injection analysis. TrAC - Trends in Analytical Chemistry 22 225-231. 

Figure 1 Schematic illustration of flowing stream manifolds devised for the automatic determination of relevant environmental parameters in water samples using various flow techniques (A) flow injection analysis, (B) sequential injection analysis, (C) multicommutation flow injection analysis, (D) multisyringe flow injection analysis. The sequential injection-lab-on-valve configuration is depicted in previous article Flow injection analysis-detection techniques. S, sample R, reagent C, carrier D, detector IV, injection valve HC, holding coil RC, reaction coil MV, multiposition valve SV, solenoid valve SP, syringe pump MP, multisyringe pump PP, peristaltic pump St, stopper W, waste.

M. Grand, HM. Oliveira, J. Ruzicka, C. Measures, Determination of dissolved zinc in seawater using micro-sequential injection lab-on-valve with fluorescence detection. Analyst 136 (2011) 2747—2755. 

Y. Wang, Z. Liu, G. Yao, P. Zhu, X. Hu, Q. Xu, C. Yang, Determination of cadmium with a sequential injection lab-on-valve by anodic stripping voltammetry using a nafion coated bismuth film electrode, Talanta 80 (2010) 1959-1963. 

FIGURE 2.6 Sequential injection lab-on-valve (SIA-LOV) assembly as coupled to column-separation systems using various interface modes. SP, syringe pump IV, injection valve HC, holding coil D, detector (xAC, microaffinity chromatograph. (Reprinted with permission from Miro, M., H. M. Oliveira, and M. A. Segundo. 2011. TrAC 30 153-164.)... 

Vidigal, S. S. M. R, I. V. Toth, and A. O. S. S. Rangel. 2013. Sequential injection lab-on-valve platform as a miniaturisation tool for solid phase extraction. Anal. Methods 5 585-597. 

X.-B. Long, M. Miro, E.H. Hansen, Universal approach for selective trace metal determinations via sequential injection-bead injection-Lab-on-Valve using renewable hydrophobic bead surfaces as reagent carriers, Anal. Chem. 77 (2005) 6032. 

J.H. Wang, E.H. Hansen, M. Miro, Sequential injection—bead injection—lab-on-valve schemes for on-line solid phase extraction and preconcentration of ultra-trace levels of heavy metals with determination by electrothermal atomic absorption spectrometry and inductively coupled plasma mass spectrometry, Anal. Chim. Acta 499 (2003) 139. 

Wang J, Hansen EH, and Miro M (2003) Sequential injection-bead injection-lab-on-valve schemes for on-line... 

J. Vichapong, R. Bluakham, S. Srijaranai, K. Grudpan, Sequential injection-bead injection-lab-on-valve coupled to high-performance hquid chromatography for online renewable microsolid-phase extraction of carbamate residues in food and enviromnental samples, J. Sep. Sci. 34 (2011) 1574—1581. 

Development of the sequential injection analyser, as well as intensive studies exploiting beads (including magnetic beads) [80—82], led to the appearance of flow analysers incorporating bead injection [83] and lab-on-valve [84] devices. 

Sequential injection analysis with lab-on-valve was conceived by Ruzicka in 2000 [84] as a progression of the sequential injection system towards downscaling. All components are integrated in a single unit mounted on a multi-position valve. The detector compartment is reduced and placed very close to the sample inlet, thus minimising the required volumes of sample, reagent and wash solution. 

The multi-port selection valve of a sequential injection analyser can be regarded as an advanced commuting device, which selects one inlet port to be commuted to any one outlet port at a time. Also, the entire manifold can be accommodated in such a valve, leading to the lab-on-valve concept [84]. 

C.-H. Wu, L. Scampavia, J. Ruzicka, B. Zamost, Micro sequential injection fermentation monitoring of ammonia, glycerol, glucose, and free iron using the novel lab-on-valve system, Analyst 126 (2001) 291. 

J. Ruzicka, Lab-on-valve universal microflow analyzer based on sequential and bead injection, Analyst 125 (2000) 1053. 

The Lab-on-Valve flow system resembles the sequential injection analyser but the main components are assembled on a multi-position valve. Exploitation of optical fibres permits spectrophotometric measurements to be performed very close to the main reaction coil. The compact geometry of the system makes it attractive for, e.g., in situ assays. For more details of this system, see 2.4.2. 

Currently, pTAS [112] and sequential injection systems using the lab-on-valve approach [22] are more popular. The former exploits hydrodynamic injection and is now known as Lab-on-Chip due to the extreme reduction in dimensions. Reproducible analytical channels are made by micro-drilling, etching, photolithography or laser erasing, and different channel profiles can be obtained at a reasonable cost. 

On the other hand, sequential injection with the lab-on-valve approach (5.5.3) does not exploit the strategy of downscaling the channel diameter but decreases the channel length and maintains the same approach as used in conventional sequential injection systems. 

Pyrolysis can also be used in flow-based determinations with electrothermal atomic absorption spectrometry, as demonstrated in the determination of nickel in environmental and biological reference materials using a sequential injection system with renewable beads [313]. After analyte sorption, the beads were directed towards the furnace of the spectrometer and stopped there pyrolysis was accomplished as usual in order to release the analyte and destroy the beads. This innovation has often been exploited in the lab-on-valve system, but spectrophotometric applications have not been proposed to date. 

J. Jakmunee, L. Pathimapomlert, S.K. Hartwell, K. Grudpan, Novel approach for mono-segmented flow micro-titration with sequential injection using a lab-on-valve system a model study for the assay of acidity in fruit juices, Analyst 130 (2005) 299. 

Micro-sequential injection environmental monitoring of nitrogen and phosphate in water using lab-on-valve system furnished with a microcolumn. HC holding coil LOV lab-on-valve RC reaction coil. 

Beads packed in microcolumns is the most reported in literature, since users can customize the quantity of resin according to the capacity of it, to the volume of sample to be loaded, and to the minimum detectable activity (MDA) of the detector used. In general, packing is manually replaced in flow systems based on flow injection analysis G A), sequential injection analysis (SIA), multisyringe flow injection analysis (MSFIA) and multipumping flow systems (MPFS). By the contrary, lab on valve (LOV) allows the manipulation of heterogeneous solutions, i.e. bead injection, achieving the automated replacement of the resin. In Chapter 3 are described in detail the parts of the microcolumns and the way to fill them. Table 8.1 summarizes the variety of available resins from TrisKem International [4]. 

P. Ampan, J. Ruzicka, R. Atallah, G.D. Christian, J. Jakmunee, and K. Grudpan. Exploiting sequential injection analysis with bead injection and lab-on-valve for determination of lead using electrothermal atomic absorption spectrometry. Analytica Chimica Acta 499 167-172,2003. 

The development of bead injection analysis (BIA), a variant of SIA, allowed the manipulation of surface-modified beads for chemical assays involving chemical processes in the heterogeneous phase (Ruzicka et al., 1993). The lab-on-valve (LOV) concept provided a further impetus toward miniaturization in flow analysis, minimization of reagent consumption, and scope for more sophisticated sample handling (Ruzicka, 2000). Finally, the introduction of sequential injection chromatography (SIC) made possible the direct hyphenation of flow manifolds with separation columns, enabling multiparametric assays, which have always been a challenge in flow-based analysis (Satinsky et al., 2003). 

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