About eight years ago, a new automation approach and flow technique called "Lab-In-Syringe" was proposed. It was derived from previous flow techniques, all based on handling reagent and sample solutions in a flow manifold. To date Lab-In-Syringe has evidently gained the interest of researchers in many countries, with new modifications, operation modes, and technical improvements still popping up. It has proven to be a versatile tool for the automation of sample preparation, particularly, liquid-phase microextraction approaches. This article aims to assist newcomers to this technique in system planning and setup by overviewing the different options for configurations, limitations, and feasible operations. This includes syringe orientation, in-syringe stirring modes, in-syringe detection, additional inlets, and addable features. The authors give also a chronological overview of technical milestones and a critical explanation on the potentials and shortcomings of this technique, calculations of characteristics, and tips and tricks on method development. Moreover, a comprehensive overview of the different operation modes of Lab-In-Syringe automated sample pretreatment is given focusing on the technical aspects and challenges of the related operations. We further deal with possibilities on how to fabricate required or useful system components, in particular by 3D printing technology, with over 20 different elements exemplarily shown. Finally, a short discussion on shortcomings and required improvements is given.
- Keywords
- 3D printing of instrument elements, Lab-In-Syringe, automation of sample pretreatment, potentials and troubles, system setup and operation modes, tips and tricks in method development,
- MeSH
- Chemistry Techniques, Analytical instrumentation methods standards MeSH
- Syringes * MeSH
- Automation, Laboratory * MeSH
- Limit of Detection MeSH
- Reproducibility of Results MeSH
- Publication type
- Journal Article MeSH
Two operational modes for Lab-In-Syringe automation of direct-immersion single-drop microextraction have been developed and critically compared using lead in drinking water as the model analyte. Dithizone was used in the presence of masking additives as a sensitive chromogenic complexing reagent. The analytical procedure was carried out inside the void of an automatic syringe pump. Normal pump orientation was used to study extraction in a floating drop of a toluene-hexanol mixture. Placing the syringe upside-down allowed the use of a denser-than-water drop of chloroform for the extraction. A magnetic stirring bar was placed inside the syringe for homogenous mixing of the aqueous phase and enabled in-drop stirring in the second configuration while resulting in enhanced extraction efficiency. The use of a syringe as the extraction chamber allowed drop confinement and support by gravitational differences in the syringe inlet. Keeping the stirring rates low, problems related to solvent dispersion such as droplet collection were avoided. With a drop volume of 60 µL, limits of detection of 75 nmol L-1 and 23 nmol L-1 were achieved for the floating drop extraction and the in-drop stirring approaches, respectively. Both methods were characterized by repeatability with RSD typically below 5%, quantitative analyte recoveries, and analyte selectivity achieved by interference masking. Operational differences were critically compared. The proposed methods permitted the routine determination of lead in drinking water to be achieved in less than 6 min.
- Keywords
- Automation, Direct-immersion single-drop microextraction, Drinking water, In-drop stirring microextraction, Lab-In-Syringe, Lead, dithizone assay,
- MeSH
- Automation * MeSH
- Syringes * MeSH
- Magnetic Phenomena MeSH
- Liquid Phase Microextraction * instrumentation MeSH
- Lead analysis MeSH
- Publication type
- Journal Article MeSH
- Names of Substances
- Lead MeSH
A novel approach to the automation technique Lab-In-Syringe, also known as In-Syringe Analysis, is proposed which utilizes a secondary inlet into the syringe void, used as a size-adaptable reaction chamber, via a channel passing through the syringe piston. This innovative approach allows straightforward automation of head-space single-drop microextraction, involving accurately controlled drop formation and handling, and the possibility of on-drop analyte quantification. The syringe was used in upside-down orientation and in-syringe magnetic stirring was carried out, which allowed homogenous mixing of solutions, promotion of head-space analyte enrichment, and efficient syringe cleaning. The superior performance of the newly developed system was illustrated with the development of a sensitive method for total ammonia determination in surface waters. It is based on head-space extraction of ammonia into a single drop of bromothymol blue indicator created inside the syringe at the orifice of the syringe piston channel and on-drop sensing of the color change via fiber optics. The slope of the linear relationship between absorbance and time was used as the analytical signal. Drop formation and performance of on-drop monitoring was further studied with rhodamine B solution to give a better understanding of the system's performance. A repeatability of 6% RSD at 10 μmol L(-1) NH3, a linear range of up to 25 μmol L(-1) NH3, and a limit of detection of 1.8 μmol L(-1) NH3 were achieved. Study of interferences proved the high robustness of the method towards humic acids, high sample salinity, and the presence of detergents, thus demonstrating the method superiority compared to the state-of-the-art gas-diffusion methods. A mean analyte recovery of 101.8% was found in analyzing spiked environmental water samples.
BACKGROUND: Alkylphenols are water contaminants of strong endocrine disruptive potential. Sample preparation is generally imperative to improve sensitivity and minimize matrix effects. Dispersive solid phase extraction is a powerful alternative to cartridge-based sorbent extraction omitting backpressure problems and reducing procedural time. Herein, solvent-dissolvable sorbents offer the advantages of easy and cost-efficient production, efficiency, and full analyte recovery, while eluates can be directly submitted to instrumental determination. Despite the potential to reduce environmental impact and enhance reproducibility, there is a lack of automation attempts. RESULTS: A fully automated solvent-assisted dispersive solid phase extraction method was developed for selected alkylphenols based on the technique Lab-In-Syringe. The void of automatic bidirectional syringe pump was used as mixing and extraction vessel. The iron(III) thenoyltrifluoroacetonate complex was used as novel dissolvable sorbent. 40 μL complex solution was dispersed in the sample, leading to the precipitation of 0.4 mg sorbent. Extraction occurred within 40 s and was accelerated by in-syringe magnetic stirring. The sorbent was retained on a melamine foam packing in the syringe inlet, dissolved in a methanolic solution of ascorbic acid, and injected into online-coupled HPLC. Linear working ranges were achieved from 1 to 1000 μg/L with sub-ppb detection limits and accuracies ranging from 98.3 to 110 %. SIGNIFICANCE: In this work, we explored for the first time automated in-syringe automated dispersive SPE based on a dissolvable sorbent. Parallel operation of sample pretreatment and separation enabled throughputs of 4.5/h with typically <5 % RSD and preconcentrations of 16.4-21.2. AGREE greenness evaluation yielded a score of 0.59.
- Keywords
- Alkylphenols, High performance liquid chromatography, Iron(III) thenoyltrifluoroacetonate complex, Lab-in-syringe automation, Solvent-assisted dispersive solid phase Extraction,
- MeSH
- Adsorption MeSH
- Automation MeSH
- Water Pollutants, Chemical * analysis isolation & purification MeSH
- Chromatography, Liquid MeSH
- Phenols * analysis isolation & purification chemistry MeSH
- Syringes MeSH
- Limit of Detection MeSH
- Solid Phase Microextraction * instrumentation methods MeSH
- Chromatography, High Pressure Liquid MeSH
- Ferric Compounds * chemistry MeSH
- Publication type
- Journal Article MeSH
- Names of Substances
- Water Pollutants, Chemical * MeSH
- Phenols * MeSH
- Ferric Compounds * MeSH
An automated methodology for magnetic dispersive solid phase microextraction integrating bead injection approach for renewable sorbent introduction is presented for the first time and was successfully applied to the enrichment of water contaminants. For this purpose, a simple procedure was developed for the functionalization of commercial SupelTM-Select HLB (Hydrophilic modified styrene polymer) sorbent beads that allowed embedding magnetite nanoparticles (Fe3O4). The sorbent was then used in a dispersive solid phase extraction procedure that was carried out entirely inside the void of an automatic syringe pump following the flow-batch concept of Lab-In-Syringe including automated renewal of the sorbent for each analysis. Mixing processes, sorbent dispersion, and sorbent recovery were enabled by using a strong magnetic stirring bar, fabricated from a 3D printed polypropylene casing and neodymium magnets, inside the syringe. The final extract was submitted to online coupled liquid chromatography with spectrometric detection. System and methodology were applied to determine mebendazole, bisphenol A, benzyl 4-hydroxybenzoate, diclofenac, and triclosan selected as models from different groups of environmental contaminants of current concern. Experimental parameters including extraction and elution times, composition and volume of eluent, and bead recollection were optimized. Required system elements were produced by 3D printing. Enlarging the sample volume by repeated extraction to enhance the sensitivity of the method was studied. Using double extraction from 3.5 mL, limits of detection ranged from 1.2 μg L-1 to 6.5 μg L-1 with an RSD (n = 6) value less than 7% for all the analytes at 25 μg L-1 level. The method was linear in the range of 5-200 μg L-1 and was successfully implemented for the analysis of surface waters with analyte recoveries ranging from 78.4% to 105.6%.
- Keywords
- Dispersive solid phase extraction, Environmental contaminants, High-performance liquid chromatography, Lab-in-syringe automation technique, Magnetic-functionalized sorbents,
- MeSH
- Solid Phase Extraction MeSH
- Syringes MeSH
- Ferrosoferric Oxide * MeSH
- Water * chemistry MeSH
- Chromatography, High Pressure Liquid methods MeSH
- Publication type
- Journal Article MeSH
- Names of Substances
- Ferrosoferric Oxide * MeSH
- Water * MeSH
A double-stage Lab-In-Syringe automated extraction procedure coupled online to HPLC for the determination of four sulfonamides in urine has been developed. Our method is based on homogeneous liquid-liquid extraction at pH 3 using water-miscible acetonitrile with induction of phase separation by the addition of a saturated solution of kosmotropic salts MgSO4 and NaCl. The procedure allowed extraction of the moderately polar model analytes and the use of a solvent that is compatible with the used separation technique. The automated sample preparation system based on the stirring-assisted Lab-In-Syringe approach was coupled on-line with HPLC-UV for the subsequent separation of the sulfonamide antibiotics. To improve both preconcentration factor and extract cleanup, the analytes were trapped at pH 10 in an anion-exchange resin cartridge integrated into the HPLC injection loop thus achieving a double-stage sample clean-up. Analytes were eluted using an acidic HPLC mobile phase in gradient elution mode. Running the analytes separation and the two-step preparation of the following sample in parallel reduced the total time of analysis to mere 13.5 min. Limits of detection ranged from 5.0 to 7.5 μg/L with linear working ranges of 50-5000 μg/L (r2 > 0.9997) and RSD ≤ 5% (n = 6) at a concentration level of 50 μg/L. Average recovery values were 102.7 ± 7.4% after spiking of urine with sulfonamides at concentrations of 2.5 and 5 mg/L followed by 5 times dilution. To the best of our knowledge, the use of Lab-In-Syringe for the automation of coupled homogeneous liquid-liquid extraction and SPE for preparation of the complex matrices suitable for separation techniques is here presented for the first time.
- Keywords
- Homogeneous liquid-liquid extraction, Lab-in-syringe, Online solid-phase extraction, Salting-out, Sulfonamides, Urine,
- MeSH
- Anti-Bacterial Agents * analysis MeSH
- Sodium Chloride * MeSH
- Liquid-Liquid Extraction MeSH
- Solid Phase Extraction MeSH
- Syringes MeSH
- Sulfonamides MeSH
- Chromatography, High Pressure Liquid MeSH
- Publication type
- Journal Article MeSH
- Names of Substances
- Anti-Bacterial Agents * MeSH
- Sodium Chloride * MeSH
- Sulfonamides MeSH
We report on the hyphenation of the modern flow techniques Lab-In-Syringe and Lab-On-Valve for automated sample preparation coupled online with high-performance liquid chromatography. Adopting the bead injection concept on the Lab-On-Valve platform, the on-demand, renewable, solid-phase extraction of five nonsteroidal anti-inflammatory drugs, namely ketoprofen, naproxen, flurbiprofen, diclofenac, and ibuprofen, was carried out as a proof-of-concept. In-syringe mixing of the sample with buffer and standards allowed straightforward pre-load sample modification for the preconcentration of large sample volumes. Packing of ca. 4.4 mg microSPE columns from Oasis HLB® sorbent slurry was performed for each sample analysis using a simple microcolumn adapted to the Lab-On-Valve manifold to achieve low backpressure during loading. Eluted analytes were injected into online coupled HPLC with subsequent separation on a Symmetry C18 column in isocratic mode. The optimized method was highly reproducible, with RSD values of 3.2% to 7.6% on 20 µg L-1 level. Linearity was confirmed up to 200 µg L-1 and LOD values were between 0.06 and 1.98 µg L-1. Recovery factors between 91 and 109% were obtained in the analysis of spiked surface water samples.
- Keywords
- Lab-In-Syringe, Lab-On-Valve, bead injection, high-performance liquid chromatography, nonsteroidal anti-inflammatory drugs, online coupling, water analysis,
- MeSH
- Anti-Inflammatory Agents, Non-Steroidal analysis MeSH
- Solid Phase Extraction * MeSH
- Surface Properties MeSH
- Water chemistry MeSH
- Chromatography, High Pressure Liquid MeSH
- Publication type
- Journal Article MeSH
- Names of Substances
- Anti-Inflammatory Agents, Non-Steroidal MeSH
- Water MeSH
We present the first automated synthesis of magnetic immunosorbents (MIS) using a lab-in-syringe (LIS) platform, facilitating antibody bioconjugation to magnetic beads via carbodiimide-mediated covalent binding. This approach is an efficient, reproducible alternative to traditional manual methods, minimizing pipetting steps, vortexing, and incubation with a reduced handling bias. Utilizing a 1 mL syringe pump with a 12-port multiposition valve and an internal magnetic stir bar enables precise mixing, bead dispersion, and magnetic capture for consistent bioconjugate synthesis. The LIS platform achieved a 99.6% bead recovery with 0.4 mg of MIS (1 μm in diameter), outperforming the 83% recovery of manual techniques, and maintained an 83% recovery at reduced scales of 0.2 mg, surpassing manual yields of 76%. As a proof-of-concept, MIS conjugated with anti-SARS-CoV2 antibodies (6 μg/400 mg beads) were synthesized and validated for viral RNA isolation from COVID-19-positive samples, demonstrating high immunocapture efficiency comparable to manual methods but with significantly reduced time and labor requirements. This automated synthesis of antibody-MIS enables the scalable, reproducible production of bioconjugated materials, supporting advanced applications in diagnostic assays, therapeutic delivery, and microfluidic integrations. The LIS approach thus enhances the scope of biomolecular conjugate synthesis, offering streamlined workflows that are suited for downstream analytical and bioanalytical applications. LIS is a versatile, automated system for preparing MIS that researchers can adapt for various targets, particularly when commercial products are unavailable, are prohibitively expensive, or require custom carriers.
- Publication type
- Journal Article MeSH
This article aims to provide an overview on the transition from earlier laboratory automation using analytical flow approaches toward today's applications of flow methodologies, recent developments, and future trends. The article is directed to flow practitioners while serving as a valuable reference to newcomers in the field in providing insight into flow techniques and conceptual differences in operation across the distinct flow generations. In the focus are the recently developed and complementary techniques Lab-On-Valve and Lab-In-Syringe. In the following, a brief comparison of the different application niches and contributions of flow techniques to past and modern analytical chemistry is given, including (i) the development of sample pretreatment approaches, (ii) the potential applicability for in-situ/on-site monitoring of environmental compartments or technical processes, (iii) the ability of miniaturization of laboratory chemistry, (iv) the unique advantages for implementation of kinetic assays, and finally (v) the beneficial online coupling with scanning or separation analytical techniques. We also give a critical comparison to alternative approaches for automation based on autosamplers and robotic systems. Finally, an outlook on future applications and developments including 3D prototyping and specific needs for further improvements is given. Graphical abstract ᅟ.
- Keywords
- Automation and miniaturization, Flow techniques, Hyphenation, Lab-On-Valve and Lab-In-Syringe, Monitoring and surveillance, Sample pretreatment,
- Publication type
- Journal Article MeSH
Continuous magnetic stirring-assisted dispersive liquid-liquid extraction followed by dispersive backextraction as a novel pre-treatment technique for adaptable and milliliter volumes of environmental samples has been developed. The procedure was automated using the technique "Lab-In-Syringe". The void of the automated syringe pump was used as size-adaptable extraction chamber. By a flow channel in the syringe piston, continuous flow through the syringe void was enabled. 1-Octanol was used as an extractant and dispersed by the action of a magnetic stirring bar, which was placed inside the syringe and driven by an external rotating magnetic field. Extract washing and dispersive backextraction in an alkaline aqueous acceptor phase were carried out after the preceding extraction from the acidified water sample. Analyte determination was achieved using multivariate spectrum analysis. The method was applied to determine priority pollutants, mono-nitrophenols, in surface water and enabled to reach limits of detection for o-, m-, p-nitrophenol (λ = 418, 390, 400 nm, respectively) of 0.14, 0.26, and 0.02 μmol L-1 (19.5, 36.2, and 2.8 μg L-1), respectively. Under optimized conditions, relative standard deviations were generally less than 5% and enrichment factors of o-, m-, p-nitrophenol 19, 25, and 21, respectively, were achieved using sample volumes of up to 24 mL. Average recoveries of o-, m-, p-nitrophenol from spiked surface water were 94, 82, and 92%, respectively. The concentration of humic acid was found 6-times reduced with respect to the analyte. In addition, adding spectral background modeling allowed nitrophenol determination with precision adequate for routine analysis.
