Sample Processing at Pittcon® 2014

The tenfold increase in speed for the analytics (GCHPLC, and SFC [supercritical fluid chromatography], all with MS) over the last decade has shifted the choke point in many workflows from analytics to “preanalytics.” Several firms have responded with automated sample processing products that save time and improve data quality. Below is a review of products for sample processing shown at Pittcon® 2014.

SoluPrep II system

Design Scientific (Holland, MI; www. designscientific.com) points out that the demand for greater accuracy from analytical instruments has prompted the automating of sample preparation based on the much more accurate “solvent weight” to “sample weight” basis. The SoluPrep II accomplishes this by automatically preparing samples for liquid chromatography, ICP, spectroscopy, viscosity, NMR, and other analyses.

The SoluPrep II improves laboratory sample solution preparation by offering the following advantages. Standards or sample solutions are prepared to an accuracy of 0.02%, be it weight/weight, normal, molal, or molar.

An approximate amount of solid sample is dissolved in the exact weight of diluent. Typically, process times are less than 2 min/sample. The SoluPrep quickly pays for itself in labor savings if the sample load is larger than 100 to 200 samples/day. Perhaps the biggest factor is the improved precision, which is a measure of data quality that is delivered by reducing human variability, including technician 1 and technician 2. Plus the SoluPrep prints self-adhesive labels for the container. A detailed report on the each sample is retained and may be copied to external data processors.

Discover SP-X automated microwave extraction system

It seems that CEM’s (Matthews, NC; www.cem.com) solution to lab protocols involving heating is to microwave it. The firm has a wide range of products including a peptide synthesizer, another unit for ashing, and several for digestion and extraction.

Microwave digestion is often popular due to low solvent consumption and short processing times. CEM introduced the Discover SP-X automated microwave extraction system, which sequentially processes 10-, 35-, and 80-mL vials. A floor-mounted infrared sensor assures consistent and accurate temperature measurement from vial to vial. The materials of construction are compatible with all solvents. An automation deck provides unattended operation. The SP-X is particularly optimized for removing organics such as plastic additives (stabilizers, antioxidants, etc.) plus oils and pesticide residues in solid foods. An optional 24-place automation deck enables “load it and leave it” operation.

Flexa™ modular purification components

Bonna-Agela Technologies (Wilmington, DE; www.bonnaagela.com) introduced Flexa™ modular purification components for automated sample prep and lab-scale prep with low-pressure LC. Modules include standalone pumps for gradient elution, absorbance, evaporative light scattering and refractive index detectors, and fraction collectors. Pumps are capable of metered flow from 1 to 100 mL/min with a Pmax of 200 psi. All are controlled by a highly intuitive Cheetah™ software controller for each module in the system.

Pressurized SPE systems

Fluid Management Systems (FMS, Watertown, MA; www.fms-inc.com) introduced two new modular systems for rapid, automated solid-phase extraction (SPE). TurboTrace™ automates the sample prep workflow, including extraction, drying, and concentration and delivery to a 2-mL sample vial. The modular design facilitates running up to eight processing stations in parallel. Moving down in price a bit, the FMS EconoTrace™ is an automated SPE system optimized for economical processing of samples or assay of organic analytes such as dioxins, polychlorinated biphenyls (PCBs), pesticides, and polyaromatic hydrocarbons (PAHs) in drinking water. Sample volumes can range from 10 mL to 4 L.

Dried blood spot analysis

Automated dried blood spot processor

Three firms introduced novel technology for dried blood spots (DBS). Spark Holland (Emmen, The Netherlands; www.sparkholland.com) and Gerstel (Mülheim an der Ruhr, Germany; www.gerstel.com) cooperated in developing an integrated automated DBS processor. Blood spots are deposited on the card in the usual manner. For analysis, Spark developed a novel, patented Flow-Through Desorption (FTD) protocol. The card is clamped between two plates that deliver and collect desorption liquid with the analytes. LC/MS usually completes the protocol. Gerstel was the first to announce an original equipment manufacturer (OEM) agreement with Spark for the DBS unit.

DBS-MS 500 dried blood spot system

For almost 50 years, CAMAG (Muttenz, Switzerland; www.camag.com) has been a leading proponent of thin layer chromatography (TLC). This year, CAMAG introduced the DBS-MS 500 dried blood spot system for LC/MS. About 15 μL of blood is spotted on four positions on the card and dried. Upon arrival in the lab, the card is placed in a card rack, and the automated DBS-MS 500 takes over and reads the card’s barcode i.d., applies an internal standard (if needed), extracts the spot in the flow-through mode, and loads the sample loop of the LC/MS for analysis. The %CV for the DBS-MS 500 for 560 consecutive replicates was 2.8% compared to 4.6% for manual punch and elute protocol.

Noviplex™ next-generation plasma sample collection tool

Shimadzu Scientific Instruments (Columbia, MD; www.ssi.shimadzu.com) and Novilytic Labs (North Webster, IN; www.novilytic.com) introduced the Noviplex™ next-generation plasma sample collection tool for LC-MS/MS of dried plasma from a fingerstick. This avoids phlebotomy and blood collection tubes. One applies a skin prick (~50–75 μL) of blood to the surface of the card. Plasma solution passes through a sandwich of membranes, which spread and filter the blood, delivering plasma to a 2.5-μL chamber that limits the liquid volume. After a minute, the filter sandwich is removed and discarded with the excess blood. Analytes (proteins and drug metabolites) are adsorbed on the disk surface. The small volume dries quickly. Intercard %CV is better than 2% by LC-MS/MS.

New phases for selective SPE

Extraction of toxins

Patulin is a toxin indicating spoilage, particularly in apples and some grains. Food safety concerns may lead to the need to extract the toxin from matrices. Supelco (Bellefonte, PA; www.sigmaaldrich.com) has developed a molecularly imprinted polymer SPE phase that selectively attracts and captures patulin, thus improving the detection limits of the assay. This phase is particularly significant, since few successful applications of molecularly imprinted polymers have been reported after 30 years of intense development.

Biotage’s (Charlotte, NC; www.biotage.com) ISOLUTE MYCO is for extracting mycotoxins from food, particularly grains. It also works for concentrating patulin from apple juice. ISOLUTE SLE+ is now available in 400-μL cartridges for supported liquid extraction (SLE).

Selective extraction of phospholipids

The presence of phospholipids in blood and plasma samples can lead to ion suppression in LC-MS/MS, which affects detection sensitivity and produces an irreproducible response. The two solutions are to use very low flow rate to MS or selectively extract the phospholipids prior to separation. Supelco chose to address the latter by introducing the HybridSPE-Phospholipid extraction cartridge packed with zirconia-silica particles. Some may recall that zirconia has strong avidity for phosphates.

Bonna-Agela Technologies introduced Cleanert® MAS for the selective removal of phospholipids. MAS uses a specially prepared diatomaceous earth in SPE cartridges or multiple-well plates for quick and easy removal of phospholipids. The workflow usually uses a protein crash followed by MAS extraction, then MAS. Side-by-side comparison with SPE, supported liquid extraction, and protein crash alone show that MAS treatment improves MS detection significantly.

Biotage is a recognized leader in solid phase extraction and supported liquid extraction, commonly used to remove assay interferences and for analyte concentration. This year Biotage introduced the ISOLUTE® PLD+, Protein and Phospholipid Removal Plates. These are generally used for removing proteins and phospholipids from blood samples. Extraction efficiency is greater than 99% and the format is automation compatible. Just dispense an appropriate amount of crash solvent, usually ACN, into each well and add the blood or plasma samples. Allow the protein to precipitate out. Then apply a vacuum or positive pressure, moving the sample through the packing bed. Proteins and phospholipids are retained and discarded, while analytes are eluted, eliminating ion-suppression interferences

SolEx™ SPE cartridges

Thermo Fisher Scientific (Sunnyvale, CA; www.thermofisher.com) introduced a broad selection of Dionex™ SolEx™ SPE cartridges that include silica and polymeric particles. These SPE cartridges are optimized for compatibility with the Dionex AutoTrace ™ 280 SPE instrument as well as small-volume SPE vacuum manifolds. SPE is usually used when the sample contains particulates or needs to be concentrated for improved detection, compared to direct injection. Cartridges are available in 1-, 3-, and 6-mL volumes. Phases include C18, C8 bonded to silica, silica, carbon, plus SAX, SCX, WCX, and WAX bonded to polystyrene/divinylbenzene beads. Application-certified phases are also available.

Dionex ASE Prep MAP

The chemists at Thermo Fisher Scientific have developed a hydroscopic polymer, the Dionex ASE Prep MAP (Moisture Adsorbing Polymer) that shows promise for removing water from samples. MAP is effective for reducing or even avoiding the tedious drying step in many sample prep protocols. It also avoids common problems with other desiccants such as clumping, precipitation, and poor recovery. For example, MAP is added to a sample in a vial. The amount of MAP is estimated from the expected water content. The formula is: 0.2 g of MAP adsorbs 1 g of water.

4100 Water/oil processor

For decades, O.I. Analytical (College Station, TX; www.oico.com) has been recognized for its efficient design of useful GC accessories. These are essential for specific applications. For example, O.I. introduced the 4100 water/soil sample processor, which processes 100 water or soil samples in industry-standard 40-mL volatile organic analysis (VOA) vials as specified in regulatory requirements. The 4100 employs a novel pneumatic vial gripper, called the VOA Constrictor™, which inflates to grip the top of labeled VOA vials—hence no more dropped vials. High-speed injection valves are used to add internal standards. Sample cooling to 10 ºC or lower is optional. For soil samples, an aliquot of water (clean or spiked) is added to the vial. The 4100 stirs and heats the slurry. Purge gas drives the VOCs to the trap.

Conclusion

Consolidation of the industry with the growth of conglomerates has depleted the ranks of large, independent firms. There are a few conspicuous large survivors. Now that the orchard is almost picked bare, the financial community has lost interest in the laboratory segment. In prior years, more than 50 financial analysts registered at Pittcon. I saw only two this year. It remains to be seen if the mega conglomerates can develop, market, and support innovative products across the diverse range they have acquired. If not, the next round may be repackaging and spin-offs. Yes, we live in interesting times.

Robert L. Stevenson, Ph.D., is Editor, American Laboratory/Labcompare; e-mail: rlsteven@ yahoo.com

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