• Analytical Science and Technology
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• v.15 no.5
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• pp.417-426
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• 2002

Inductively Coupled Plasma Dynamic Reaction Cell Quadrupole Mass Spectrometry (ICP-DRC-QMS) was characterized for the detection of the six naturally occurring calcium isotopes. The effect of the operating conditions of the DRC system was studied to get the best signal-to-noise ratio. This experiment shows that the potentially interfering ions such as $Ar^+$, ${CO_2}^+$, ${NO_2}^+$, $CNO^+$ at the calcium masses m/z 40, 42, 43, 44 and 48 were removed by flowing $NH_3$ gas at the rate of 0.7 mL/min $NH_3$ as reactive cell gas in the DRC with a RPq value (rejection parameter) of 0.6. The limits of detection for $^{40}Ca$, $^{42}Ca$, $^{43}Ca$, $^{44}Ca$, and $^{48}Ca$ were 1, 29, 169, 34, and 15 pg/mL, respectively. This method was applied to the determination of calcium in synthetic food digest samples (CCQM-P13) provided by LGC for international comparison. The isotope dilution method was used for the determination of calcium in the samples. The uncertainty evaluation was performed according to the ISO/GUM and EURACHEM guidelines. The determined mean concentration and its expanded uncertainty of calcium was ($66.4{\pm}1.2$) mg/kg. In order to assess our method, two reference samples, Riverine Water reference sample (NRCC SLRS-3) and Trace Elements in Water reference sample (NIST SRM 1643d), were analyzed.

• Journal of Food Hygiene and Safety
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• v.34 no.3
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• pp.242-250
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• 2019

An analytical method was developed for the determination of fenquinotrione, a triketone herbicide, in agricultural products. Fenquinotrione was metabolized to KIH-3653-M-2 in plants. Analyte extraction was conducted using 2% formic acid in acetonitrile and cleaned up using a hydrophillic-lipophillic balance (HLB) cartridge. The limits of detection (LOD) and quantification (LOQ) were 0.004 and 0.01 mg/kg, respectively. Matrix-matched calibration curves were linear over the calibration ranges ($0.001{\sim}0.1{\mu}g/mL$) into a blank extract with $r^2>0.99$. The recovery results for fenquinotrione and KIH-3653-M-2 ranged between 81.1 to 116.2% and 78.0 to 110.0% at different concentration levels (LOQ, $10{\times}LOQ$, $50{\times}LOQ$) with relative standard deviation (RSD) less than 4.6%. All values were corresponded with the criteria ranges requested in both the Codex (CAC/GL 40-1993, 2003) and MFDS guidelines (2016). Therefore, the proposed method can be used as an official analytical method for determination of fenquinotrione in the Republic of Korea.