Acceptance Criteria for Ultratrace HPLC−Tandem Mass Spectrometry:  Quantitative and Qualitative Determination of Sulfonylurea Herbicides in Soil

Abstract

Eight commonly used sulfonylureas (SUs: nicosulfuron, thifensulfuron methyl, metsulfuron methyl, sulfometuron methyl, chlorsulfuron, bensulfuron methyl, tribenuron methyl, and chlorimuron methyl) and deuterium-labeled nicosulfuron (nicosulfuron-d(6)), used as an internal standard, were isolated from soil by solvent extraction and identified under quantitative and qualitative ion spray LC/MS/MS conditions using the selected reaction monitoring (SRM) mode of acquisition. The lower level of quantitation for these SUs in soil was determined at the 0.05 ppb level using a TurboIonSpray adapted LC/MS interface without a precolumn split and optimizing MS/MS tuning conditions for individual SUs. The eight SUs were qualitatively identified and quantitatively determined in soil. The standard curve for each SU was linear from 0.05 to 10 ppb. This SRM LC/MS method demonstrates high sensitivity and high specificity for these SUs in soil and shows at least a 400-fold improvement in sensitivity over previous reports. Acceptance criteria for forensically valid data are suggested for qualitative SRM LC/MS experiments. These include HPLC retention time reproducibility (±2%), at least two and preferably three precursor-product ions selected, and relative abundance criteria for selected ions (±20% absolute).

LC–MS/MS determination of naringin, hesperidin and neohesperidin in rat serum after orally administrating the decoction of Bulpleurum falcatum L. and Fractus aurantii

“…The preferred approach was to compare the mass spectra and retention Table 1 Reproducibility of retention time and relative abundance observed for precursor-product ion transition from SRM analyses of hesperidin, neohesperidin and naringin in rat serum extracts (n = 5) [15] and the MS/MS mass spectra data should agree with those of a reference standard analyzed under the same conditions. However, sometimes satisfactory full-scan LC-MS/MS mass spectra cannot be obtained due to the very low levels of the target compounds in biological samples.…”

“…However, sometimes satisfactory full-scan LC-MS/MS mass spectra cannot be obtained due to the very low levels of the target compounds in biological samples. One strategy is to compare at least two and preferably three independent selected reaction monitoring (SRM) precursor/product ion transitions of target compounds with corresponding reference standards and the criteria was the absolute relative abundance of the precursor/product ion transitions agreed within ±10% [15]. The strategy in this work is to compare three independent SRM precursor/product ion transitions and the retention times of target compounds with corresponding reference standards under the same conditions.…”

Ionization and transmission efficiency in an electrospray ionization—mass spectrometry interface

“…In addition to its importance for transmission efficiency, the ESI interface on the mass spectrometer also plays a key role in ionization efficiency [17]. Adding energy to the charged droplets-such as using heated nitrogen as a background gas-enhances desolvation and liberates more analyte ions [17][18][19][20].Ion transmission efficiency, also defined as the fraction of ES current that enters the mass analyzer, has traditionally been limited by losses at the mass spectrometer inlet and at the skimmer [7,21]. It has been estimated that only about one out of every 10 3 -10 5 analyte ions generated by ESI at atmospheric pressure is actually detected using present instrument designs [7,10,22].…”

“…In addition to its importance for transmission efficiency, the ESI interface on the mass spectrometer also plays a key role in ionization efficiency [17]. Adding energy to the charged droplets-such as using heated nitrogen as a background gas-enhances desolvation and liberates more analyte ions [17][18][19][20].…”

Trace analysis of sulfonylurea herbicides in water by on-line continuous flow liquid membrane extraction–C18 precolumn liquid chromatography with ultraviolet absorbance detection

“…[1,4,[6][7][8][9][10] is the most commonly used one because 50 Because of the low dose used and chemical instabiliof the polarity and thermal instability of sulty, sulfonylureas are present at very low concenfonylureas. LC-mass spectrometry (MS) methods trations in environmental waters, which presents a [1,4,[7][8][9][10], which have the advantages of high challenge for their determination in recipient waters.…”