Keywords: Metabolomics, Automation, Solid Phase Extraction, LC-QTOF
In metabolomics studies, large sample sets have to be analyzed to allow statistical differentiation of sample types. Obviously, repeatability of the whole analytical workfl ow, including sample preparation, sample introduction, separation and detection, is hereby of the utmost importance. In this respect, automation of the sample preparation is very useful in order to reduce the analytical variability.
In a series of articles, we describe the use of the Gerstel MPS WorkStation for automated sample preparation applied to metabolomics studies. In a first part, an automated ultrasonic assisted extraction and fi ltration method was discussed. In this second part, an automated fractionation of lipid classes using solid phase extraction (SPE) is presented. The SPE fractions are concentrated using an mVAP evaporation station and re-dissolved in small amounts of solvent, followed by LC-QTOF analysis.
Keywords: SPE, Chloramphenicol, LC/MS, Automation
Solid Phase Extraction (SPE) using standard cartridges is widely regarded as the method of choice to extract analytes from samples with complex matrices or to extract and concentrate analytes from a wide variety of samples in general. In this paper, an automated SPE system is presented that is based on standard cartridges. It is shown that SPE with standard cartridges is easily and efficiently automated for use in LC/MS based determination of illegal antibiotics in food products of animal origin. An established manual SPE method was easily transferred to the GERSTEL MultiPurpose autosampler (MPS) using the SPE option under MAESTRO software control. Recovery and precision was improved while significantly reducing the time and effort required for sample preparation.
Keywords: Malachite Green, Solid Phase Extraction, LC/MS, Fish
Malachite green (MG) is a triphenyl methane dye that is highly efficient in battling fungi, bacteria and various single cell parasites. MG is traditionally used in aquaculture to treat and prevent fungal infections. MG, which is structurally related to known carcinogenic triphenylmethane dyes, is metabolized to leucomalachite green (LMG) and deposited in the fatty tissue of the fish. MG is under suspicion of being a human carcinogen and for causing damage to the human genetic material. Consumption of fish that is contaminated with MG is assumed to pose a significant health risk to humans. In 2003 the European Commission set the MRPL (minimum required performance limit) for MG and LMG to 2 μg/kg. Even though malachite green is banned as a veterinary pharmaceutical for animals used for human consumption, the authorities regularly find residues of this toxic compound or its metabolites during routine checks of fish farms. The work presented in this application note describes the configuration of a combined fully automated Solid Phase Extraction (SPE) system coupled with LC/Ion Trap MS. Method parameters are shown that provide improved detection limits for the two compounds coupled with automated sample preparation for highest laboratory productivity.
Keywords: Aflatoxins, Solid Phase Extraction, SPE, LC/MS
Aflatoxins are metabolites from molds such as aspergillus flavus and aspergillus parasiticus. Aflatoxins are classified as mycotoxins, they are among the most potent human carcinogens, found mainly in foods and feed of plant origin. High concentrations of aflatoxins have been found, for example, in pistachios, figs and cereals and aflatoxins have also been found in dairy products. Due to the high toxicity of aflatoxins, EU legislation specifies very low acceptable daily intakes and maximum residue limits (0.05-15 μg/kg). Of 17 known aflatoxins, four are mainly relevant: Aflatoxin B1, Aflatoxin B2, Aflatoxin G1 & Aflatoxin G2. This application note describes the configuration and operation of an LC/MS system combined with automated solid phase extraction and analyte derivatization for determination of the four aflatoxins listed above. Using the combined system, lower detection limits and improved chromatographic separation were achieved.
Keywords: Low Thermal Mass, LTM, Fast GC-ECD, SPE, PCB, Waste Oil
A fast SPE-GC-ECD method for the analysis of PCBs in waste oil was developed. A complete profile was obtained following SPE with a 12 minute GC run-time using a low thermal mass column heater (LTM). Full automation of the sample preparation and analysis (except sample weigh-in) enables a daily throughput of 100 samples. A wide range of concentrations can be determined using a dedicated column and Electron Capture Detection (ECD).
Keywords: Solid Phase Extraction, SPE, Liquid Chromatography, Sample Analysis, Lab Automation
Solid phase extraction (SPE) is one of the sample preparation methods most widely used by chromatographers, as demonstrated by the numerous published SPE methods found in the literature. Manual SPE cartridge formats can vary from disks through individual cartridges with a range of different volumes to 96-well plates. However, solid phase extraction methods can be tedious and time consuming when performed manually. There is therefore an increasing need for the automation of solid phase extraction methods. A robotic X-Y-Z coordinate autosampler commonly used for sample introduction in GC or HPLC can be used to perform a wide variety of sample preparation techniques using a single instrument and controlling software. The MAESTRO software allows the user to control the automation of solid phase extraction methods. In addition to ease of use and intuitive windows-based programming, the tools to optimize method parameters ensuring efficient sequence creation and maximum sample throughput. The sampler can be configured as part of a GC or LC system or as a benchtop workstation. In this study, we show that existing manual SPE methods can be transferred to standard format automation cartridges and automated using the robotic autosampler in conjunction with the software. Examples of solid phase extraction methods illustrating the conversion from manual to automated methods are shown.
Keywords: Solid Phase Extraction, SPE, LC/MS/MS, Sample Analysis, Laboratory Automation
Acrylamide is thought to be produced during the roasting process associated with coffee production. Acrylamide has been labeled as a probable human carcinogen. Due to the use of roasted coffee beans in making coffee and the high consumption of coffee world-wide, brewed coffee could be a source of daily exposure to acrylamide. Acrylamide determination has been shown to be challenging due to presence of co-extractives in the final extract. Manual solid phase extraction followed by LC-MS/MS analysis has been reported as a successful method for the determination of acrylamide from brewed coffee samples. However, performing solid phase extraction manually can be tedious and time consuming and there is increasing demand for automation of these methods. In this study, we show that a manual SPE method used for the determination of acrylamide in brewed coffee can be converted to an autosampler compatible cartridge format and automated using a robotic autosampler controlled by user-friendly software. Calibration standards prepared in freshly brewed green coffee (un-roasted) resulted in a linear calibration curve (r2=0.99) from 1 ng/mL to 500 ng/mL. Precision of the automated SPE-LC/MS/MS method was calculated as CV = 1.7 %.
Keywords: Opiates, Opioids, Cocaine, Solid Phase Extraction, SPE, Automation, GC/MS
Analyzing blood serum for opioids, cocaine and metabolites is a routine task in forensic laboratories. The most commonly used methods involve several manual or partly-automated sample preparation steps such as protein precipitation, solid phase extraction, evaporation and derivatization followed by GC/MS or LC/MS determination. In this study a comprehensively automated method is compared with a validated, partly-automated routine method. Following manual protein precipitation, the automated method relies on a MultiPurpose Sampler (MPS) to perform all remaining sample preparation steps. These include solid phase extraction (SPE), evaporation of the eluate, derivatization and introduction to the GC/MS. Quantitative analysis of close to 170 serum samples, as well as more than 50 samples of other matrices like urine, different tissues and heart blood, was performed using both methods. Cocaine, benzoylecgonine, methadone, morphine, codeine, 6-monoacetylmorphine, dihydrocodeine and 7-aminofl unitrazepam were determined quantitatively and the methods were found to produce equivalent analytical results even near the limits of quantification
Keywords: Glyphosate, LC/MS/MS, Sample Preparation, Lab Automation, Food Safety
Glyphosate and glufosinate are widely used herbicides and, thus, there is an interest in the reliable and sensitive determination of glyphosate in water and food. These pesticides are difficult to extract and analyze because of their high polarity. In this report, we describe an automated work flow for the FMOC derivatization, sample cleanup, and LC/MS/MS analysis using a GERSTEL MultiPurpose Sampler (MPS XL) configured with an online solid phase extraction (SPEXOS) module coupled to an AB SCIEX QTRAP® 4500 system for the identification and quantitation of glyphosate, its major metabolite AMPA, and glufosinate in water and food samples. The online SPE-LC/MS/MS method allowed detection and quantitation of all target pesticides in matrix samples at 10 μg/kg concentration levels with excellent reproducibility and values well within the ±20 % range.
Keywords: THC, THC-OH, THC-COOH, Serum, Solid Phase Extraction, SPE, Automation, GC/MS
This note presents a fully automated analysis system for the determination of THC and its metabolites in blood serum. Automation is based on the GERSTEL MultiPurpose Sampler (MPS) equipped for solid phase extraction and a module for automated eluate evaporation (GERSTEL mVAP). A validated, semi-automated analysis method used for routine analysis was transferred and automated using the described system. Improvements were realized such as a reduction of sample volume and the use of a smaller SPE cartridge format. The method was validated according to Society for Toxicology and Forensic Chemistry (GTFCh) guidelines. Limits of quantification below 1 ng/mL for THC and THC-OH, extraction efficiencies between 70 and 93% and RSDs between 3 and 10% were achieved.The SPE system performs sample preparation in parallel with the chromatographic run, enabling the GC/MS system to operate at maximum capacity.
Keywords: Forensics ,Veterinary, Sample Preparation, LC/MS/MS, High Throughput Lab Automation
The extraction of dried blood spots (DBS) typically involves manual intervention. First, a small disc is punched out of the center of a dried blood spot placed on a DBS card. Following solvent extraction of the sample, it is also common to include further cleanup steps, using solid phase extraction (SPE) to improve detection limits or exchanging solvents for compatibility with subsequent chromatographic separations. Modern analytical labs are looking to automate the process to help reduce solvent usage and to increase sample throughput while ensuring the high quality of the resulting data.
In this report, the complete automation of dried blood spot analysis is demonstrated and the results evaluated. A novel, automated DBS Autosampler (DBS A) automatically inserts DBS cards into a Flow Through Desorption (FTD™) cell in which individual blood spots are rapidly and effectively desorbed. The DBS A is integrated into a complete cleanup and analysis system using online SPE with replaceable cartridges combined with automated injection to an LC/MS/ MS system. Automated DBS extraction methods for a variety of analytes from different matrices are examined along with the use of different SPE cartridge sorbents. The resulting precision and accuracy data are provided.