Use Of Solid-phase Extraction Cartridges Research Articles

Fast and simple method for the detection and quantification of 15 synthetic dyes in sauce, cotton candy, and pickle by liquid chromatography/tandem mass spectrometry

A simple and sensitive liquid chromatography/tandem mass spectrometry (LC-MS/MS) method for the simultaneous determination of 15 illegal dyes (Sudan I, Sudan II, Sudan III, Sudan IV, Sudan Red G, Sudan Orange G, Sudan Red 7B, Para Red, Dimethyl Yellow, Rahodamine B, Sudan Black B, Sudan Red B, Auramine O, Toluidine Red and Orange II) was developed and validated in sauce, cotton candy, and pickle. The samples were extracted with acetonitrile without the use of solid-phase extraction cartridges. Chromatographic separation was achieved on a Zorbax Eclipse Plus C18 column with a flow rate of 500 µL/min at 45 °C, using a gradient elution with A (10 mM ammonium formate in water with 0.1% formic acid) and B (10 mM ammonium formate in acetonitrile (ACN) with 0.1% formic acid) as the mobile phase. The detection was performed on a AB Sciex 6500 Qtrap mass analyzer under multiple reaction monitoring mode. Limit of detection, quantification, linearity, and precision were determined during the validation process. Recoveries ranged from 82% to 119% for all synthetic dyes, in exception to Orange II in cotton candy and pickle, where signal was suppressed due to high matrix interference and poor ionization. This method offers a simple and rapid approach to detect and quantify prohibited dyes in foodstuff that can be utilized in food contaminant laboratories.

Determination of 20 synthetic dyes in chili powders and syrup-preserved fruits by liquid chromatography/tandem mass spectrometry

A liquid chromatography/tandem mass spectrometry (LC-MS/MS) method is developed to simultaneously determine 20 synthetic dyes (New Coccine, Indigo Carmine, Erythrosine, Tartrazine, Sunset Yellow FCF, Fast Green FCF, Brilliant Blue FCF, Allura Red AC, Amaranth, Dimethyl Yellow, Fast Garnet GBC, Para Red, Sudan I, Sudan II, Sudan III, Sudan IV, Sudan Orange G, Sudan Red 7B, Sudan Red B, and Sudan Red G) in food samples. This method offers high sensitivity and selectivity through the selection of two fragment ion transitions under multiple reaction monitoring mode to satisfy the requirements of both quantitation and qualitation. Using LC-MS/MS, the newly developed extraction protocol used in this study is rapid and simple and does not require the use of solid-phase extraction cartridges. The linearities and recoveries of the method are observed at the concentration range of 0.10–200 μg/kg and more than 90% for all dyes, respectively. The method has been successfully applied to screen 18 commercial chili powders and six commercial syrup-preserved fruits purchased from retail establishments in Taipei City. The results show that three legal food dyes, Tartrazine, and/or Sunset Yellow FCF, and/or New Coccine, are present in some syrup-preserved fruits. Amaranth, an illegal food dye in certain countries but declared illegal in Taiwan, is found in an imported syrup-preserved fruit.

Novel Automated Extraction Method for Quantitative Analysis of Urinary 11-nor- 9-Tetrahydrocannabinol-9-Carboxylic Acid (THC-COOH)

An automated extraction method for extracting the major urinary metabolite of cannabis, 11-nor-Delta(9)-tetrahydrocannabinol-9-carboxylic acid (THC-COOH) was developed on the four-probe Gilson ASPEC XL4trade mark solid-phase extraction (SPE) system. The method works on liquid-liquid extraction principles but does not require the use of SPE cartridges. The limits of detection and quantitation and the upper limit of linearity (ULOL) of the developed method were found to be 1, 2, and 1,500 ng/mL, respectively. There was no detectable carry over after 10,000 ng/mL analyte. For a batch of 76 samples, the process uses less than 100 mL methanol, 450 mL extracting solvent hexane/ethyl acetate (5:1, v/v) and 1 L rinsing solvent, 30% methanol in water. The automated extraction process takes 5 h to complete. Precision and accuracy of the method are comparable to both manual liquid-liquid extraction and automated SPE methods. The method has proven to be a simple, speedy, and economical alternative to the currently popular automated SPE method for the quantitative analysis of urinary THC-COOH.

Perchlorate Analysis Using Solid-Phase Extraction Cartridges

Perchlorate is a compound of increasing concern as an environmental contaminant and is being regulated at increasingly stringent levels. Reliable methods are needed to consistently analyze perchlorate at low concentration levels. This research investigates the use of solid-phase extraction cartridges as an alternative to large-volume injection loops to achieve low-level (microg/L level) perchlorate quantitation. The method involves commercially available strong anion exchange (SAX) cartridges. Water samples are filtered (100 to 1000 mL) using the cartridge, which removes the perchlorate from the solution by anion exchange. Then, after the desired volume is filtered, the perchlorate is extracted using 4 mL of 1% NaOH. In addition, a cleanup method is developed to remove competing anions (chloride, sulfate, and carbonate) that are often found in environmental samples. Analyses are performed with an ion chromatograph using a 10-microL injection loop, yielding a perchlorate method detection limit (MDL) of 210 microg/L. One-liter volumes of a 2-microg/L perchlorate spiked deionized water solution are filtered with SAX SPE. Following extraction and analysis, an MDL of 0.82 microg/L is obtained, comparable to that found for 1-mL injection loop systems (reported as low as 0.53 microg/L). MDL studies are then conducted on perchlorate-amended groundwater (solution concentration of 70 microg/L) and surface water (solution concentration of 10 microg/L) using a filtration volume of 200 mL. The MDLs are 6.7 microg/L for the groundwater and 2.4 microg/L for the surface water.

Indoor air sampling of organophosphate triesters using solid phase extraction (SPE) adsorbents

In this paper we demonstrate the use of SPE cartridges for sampling of organophosphate triesters in indoor air by adsorptive enrichment. The method has been optimised for the sampling and analysis of organophosphate triesters using a 25 mg aminopropyl silica SPE cartridge. The same cartridge is used for the active air sampling as well as for the subsequent extraction and clean-up of the sample. This makes the method fast and eliminates some tedious and time-consuming manual sample handling steps. Sampling and extraction efficiency was high for the investigated organophosphates, and limit of detection was in the range 0.1-0.3 ng m(-3). The method was applied to measurements of organophosphate triesters in two lecture halls and an electronics dismantling facility, and was compared with results from common filter/adsorbent sampling at each site. Analysis was made by GC with selective detection by NPD set in phosphorus mode, and by GC-MS. Thirteen organophosphate triesters (not counting isomers) were detected in the electronic dismantling facility. Chlorinated organophosphate triesters were detected in all locations with concentrations over 1 microg m(-3) in the lecture halls. This kind of adsorptive enrichment using an SPE cartridge could be adjusted to other types of analytes as well.

Use of solid-phase extraction cartridges with differential-pulse cathodic stripping voltammetry at a hanging mercury drop electrode: determination of nedocromil sodium and pentamidine isethionate in urine

Nedocromil sodium (an antiasthma drug) and pentamidine isethionate (an antiprotozoal agent) were determined in urine by cathodic stripping voltammetry after adsorptive accumulation at a hanging mercury drop electrode as examples of the use of solid-phase extraction cartridges with this technique. Prior separation from matrix interferents was necessary and this was carried out using either a C18 solid-phase extraction cartridge or liquid–liquid extraction. For nedocromil, a recovery of 100.5 ± 6.5%(± 2 standard deviations) was obtained from urine spiked with 0.42 µg ml–1 of the drug using a C18 cartridge (five determinations). A 97% recovery of pentamidine isethionate was obtained by solid-phase extraction when the drug was added to urine at a level of 1.48 µg ml–1. At lower levels of pentamidine isethionate, better recovery was obtained using liquid–liquid extraction: recoveries of between 60 and 100% were obtained at levels of 0.04–29.6 µg ml–1. Linear calibration graphs were obtained for the determination of both drugs at concentration levels in the measured solution lower than 1 × 10–7 mol l–1(i.e., less than approximately 0.05 µg ml–1): standard additions method was preferred for quantification. Relative standard deviations of 4.5% for the determination of pentamidine isethionate and of 5.2% for the determination of nedocromil (n= 5) were obtained for urine samples containing 2.96 µg ml–1 of pentamidine isethionate and 0.42 µg ml–1 of nedocromil.