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
Lab-In-Syringe direct immersion single drop microextraction is proposed as an automated sample pretreatment methodology and coupled online to HPLC with fluorescence detection for the determination of fluoroquinolones in environmental waters. For the first time, a drop of a natural deep eutectic solvent (NADES), synthesized from hexanoic acid and thymol, has been used as an extractant in automated single-drop microextraction. The extraction procedure was carried out within the 5 mL void of an automatic syringe pump. A 9-position head valve served the aspiration of all required solutions, air, waste disposal, and hyphenation with the HPLC instrument. Sample mixing during extraction was done by a magnetic stirring bar placed inside the syringe. Only 60 μL of NADES were required omitting toxic classical solvents and improving the greenness of the proposed methodology. By direct injection, linear working ranges between 0.1 and 5 μg L-1 were achieved for all fluoroquinolones. The limit of quantification values and enrichment factors ranged from 20 ng L-1 to 30 ng L-1 and 35 to 45, respectively. Accuracies obtained from the analysis of spiked surface water and wastewater treatment plant effluent analysis at two concentration levels (0.5 and 4 μg L-1) ranged from 84.6% to 119.7%, with RSD values typically <3%.
- Keywords
- Automation of sample preparation, Directly immersed single drop microextraction, Fluoroquinolone antibiotics, Lab-in-syringe, Natural deep eutectic solvent, Online coupling to HPLC,
- MeSH
- Automation MeSH
- Fluoroquinolones * MeSH
- Deep Eutectic Solvents MeSH
- Syringes MeSH
- Limit of Detection MeSH
- Liquid Phase Microextraction * methods MeSH
- Immersion MeSH
- Solvents chemistry MeSH
- Chromatography, High Pressure Liquid MeSH
- Publication type
- Journal Article MeSH
- Names of Substances
- Fluoroquinolones * MeSH
- Deep Eutectic Solvents MeSH
- Solvents 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
Pharmaceutical residues in environmental waters continue to raise significant public and ecological concerns, necessitating advanced analytical methodologies for their monitoring. In this work, a novel Lab-In-Syringe automated dispersive micro solid-phase extraction (LIS-DMSPE) method was developed to determine three angiotensin receptor blockers in water samples. The approach was based on the in situ synthesis of Ni/Fe-layered double hydroxides within the void of an automatic syringe pump through controlled pH adjustment following the aspiration of precursor solutions. This enabled the rapid formation of the adsorbent and eliminated the need for pre-synthesized or magnetized sorbents. Enhanced sedimentation speed, achieved by increasing ionic strength with NaNO3, allowed isolating the sedimented sorbent from the sample matrix without centrifugation and filtration. The instrumental setup was successfully coupled online with HPLC-DAD. After in-syringe washing and dissolving the sediment, the low organic solvent content of the extract enabled large-volume injection (200 μL), thereby boosting sensitivity. Parameters including type and volume of precursor solution, NaNO3 addition, buffer volume and pH, stirring rate and time, and the composition of elution/destruction solution were carefully optimized. Recoveries and enrichment factors were in the ranges of 62.0-88.7 % and 13.3-25.8, respectively. The method was linear over a 5-200 μg L-1 concentration range for all analytes. Accuracies ranged from 88.7 % to 105.8 % for real samples spiked at two concentrations with RSDs less than 3.5 %. To our knowledge, this is the first report on a LIS-DMSPE method that does not require pre-synthesis or magnetization of the sorbent for extraction and uses accelerated sedimentation for adsorbent isolation.
- Keywords
- Angiotensin receptor blockers, Automation, Dispersive micro solid-phase extraction, Lab-In-Syringe, Large volume injection, Layered double hydroxides,
- MeSH
- Adsorption MeSH
- Angiotensin Receptor Antagonists * analysis isolation & purification MeSH
- Automation MeSH
- Water Pollutants, Chemical * analysis isolation & purification MeSH
- Solid Phase Extraction MeSH
- Hydroxides * chemistry MeSH
- Syringes MeSH
- Solid Phase Microextraction * methods instrumentation MeSH
- Nickel * chemistry MeSH
- Iron * chemistry MeSH
- Publication type
- Journal Article MeSH
- Names of Substances
- Angiotensin Receptor Antagonists * MeSH
- Water Pollutants, Chemical * MeSH
- Hydroxides * MeSH
- Nickel * MeSH
- Iron * MeSH
Online coupling of Lab-In-Syringe automated headspace extraction to gas chromatography has been studied. The developed methodology was successfully applied to surface water analysis using benzene, toluene, ethylbenzene, and xylenes as model analytes. The extraction system consisted of an automatic syringe pump with a 5 mL syringe into which all solutions and air for headspace formation were aspirated. The syringe piston featured a longitudinal channel, which allowed connecting the syringe void directly to a gas chromatograph with flame ionization detector via a transfer capillary. Gas injection was achieved via opening a computer-controlled pinch valve and compressing the headspace, upon which separation was initialized. Extractions were performed at room temperature; yet sensitivity comparable to previous work was obtained by high headspace to sample ratio VHS/VSample of 1.6:1 and injection of about 77% of the headspace. Assistance by in-syringe magnetic stirring yielded an about threefold increase in extraction efficiency. Interferences were compensated by using chlorobenzene as an internal standard. Syringe cleaning and extraction lasting over 10 min was carried out in parallel to the chromatographic run enabling a time of analysis of <19 min. Excellent peak area repeatabilities with RSD of <4% when omitting and <2% RSD when using internal standard corrections on 100 μg L-1 level were achieved. An average recovery of 97.7% and limit of detection of 1-2 μg L-1 were obtained in analyses of surface water.
- Keywords
- Btex, Gas chromatography – flame ionization detection, Headspace extraction, Magnetic-stirring Lab-In-Syringe, On-line coupling,
- MeSH
- Automation MeSH
- Benzene analysis isolation & purification MeSH
- Benzene Derivatives analysis isolation & purification MeSH
- Limit of Detection MeSH
- Solid Phase Microextraction MeSH
- Flame Ionization methods MeSH
- Temperature MeSH
- Toluene analysis isolation & purification MeSH
- Water chemistry MeSH
- Xylenes analysis isolation & purification MeSH
- Publication type
- Journal Article MeSH
- Names of Substances
- Benzene MeSH
- Benzene Derivatives MeSH
- ethylbenzene MeSH Browser
- Toluene MeSH
- Water MeSH
- Xylenes 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
A sample preparation method involving tandem implementation of protein precipitation and salting-out homogenous liquid-liquid extraction was developed for the determination of beta-blockers in serum. The entire procedure was automated using a computer-controlled syringe pump following the Lab-In-Syringe approach. It is based on the denaturation of serum proteins with acetonitrile followed by salt-induced phase separation upon which the proteins accumulate as a compact layer at the interphase of the solutions. The extract is then separated and diluted in-syringe before being submitted to online coupled UHPLC-MS/MS. A 1 mL glass syringe containing a small stir bar for solution mixing at up to 3000 rpm, was used to deal with sample volumes as small as 100 μL. A sample throughput of 7 h-1 was achieved by performing the chromatographic run and sample preparation procedure in parallel. Linear working ranges were obtained for all analytes between 5 and 100 ng mL-1, with LOD values ranging from 0.4 to 1.5 ng mL-1. Accuracy values in the range of 88.2-106% and high precision of <11% RSD suggest applicability for routine analysis that can be further improved using deuterated standards.
- Keywords
- Beta-blockers, Centrifugation-less protein precipitation, Lab-in-syringe automation, Salting-out homogenous liquid-liquid extraction, Serum,
- MeSH
- Sodium Chloride MeSH
- Liquid-Liquid Extraction methods MeSH
- Syringes * MeSH
- Tandem Mass Spectrometry * MeSH
- Chromatography, High Pressure Liquid methods MeSH
- Publication type
- Journal Article MeSH
- Names of Substances
- Sodium Chloride 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
