Estimation of the uncertainty of the quantification limit

Badocco, Denis; Lavagnini, Irma; Mondin, Andrea; Pastore, Paolo

doi:10.1016/j.sab.2014.03.013

Cited by 11 publications

(9 citation statements)

References 10 publications

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“…The instrument was optimized to achieve optimum sensitivity and stability according to the manufacturer's recommendations. Detection limits are calculated following the reported procedures [ 23 ]. An attempt was also made to detect organic contaminants from the sample, using previously reported procedures [ 24 ], but none was observed above background level.…”

Section: Methodsmentioning

confidence: 99%

Long-distance connections in the Copper Age: New evidence from the Alpine Iceman’s copper axe

et al. 2017

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25 years after the discovery in the Ötztal Italian Alps, the 5,300-year-old mummy keeps providing key information on human biological and medical conditions, aspects of everyday life and societal organization in the Copper Age. The hand axe found with the body of the Alpine Iceman is one of the rare copper objects that is firmly dated to the early Copper Age because of the radiocarbon dating of the axe wooden shaft. Here we report the measurement of the lead isotope ratios of the copper blade. The results unambiguously indicate that the source of the metal is the ore-rich area of Southern Tuscany, despite ample evidence that Alpine copper ore sources were known and exploited at the time. The experimental results are discussed within the framework of all the available coeval archaeometallurgical data in Central-Southern Europe: they show that the Alps were a neat cultural barrier separating distinct metal circuits. The direct evidence of raw metal or object movement between Central Italy and the Alps is surprising and provides a new perspective on long-distance relocation of goods and relationships between the early Copper Age cultures in the area. The result is in line with the recent investigations re-evaluating the timing and extent of copper production in Central Italy in the 4th millennium BC.

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Section: Methodsmentioning

confidence: 99%

Long-distance connections in the Copper Age: New evidence from the Alpine Iceman’s copper axe

et al. 2017

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“…Limits of detection (LODs) were also experimentally estimated through a specific calibration at four concentration levels close to the respective LOD values by applying a recent statistical method reported in the literature [18,19], accounting for their standard deviation.…”

Section: Quantification Of Target Compounds and Methods Performance Evmentioning

confidence: 99%

“…LODs were rigorously calculated on the basis of the lowest four points of the calibration curve (n=3) according to the Voigtmann method [18]. Furthermore, the evaluation of their standard deviation was assessed following a recent statistical approach [19]. Results are reported in Table 2.…”

Section: Validationmentioning

confidence: 99%

“…LODs and their respective standard deviation (SD) calculated as proposed in[18,19] Accuracy of target analytes calculated from five different matrices (see section BSample collection and preparation^) spiked at three concentration levels (n=5, N=25) lot only in the 2014 after the optimization of the presented LC-HRMS method. In this case, the MFE post-run analysis showed two relevant signals identified as homosildenafil (experimental m/z 489.2273, Δm=−1.2 ppm) or its isomer and one of the three isobaric compounds having a theoretical value m/z 505.2050, namely thiodimethylsildenafil, thiomethisosildenafil and thiohomosildenafil.…”

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confidence: 99%

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“One-shot” analysis of PDE-5 inhibitors and analogues in counterfeit herbal natural products using an LC-DAD-QTOF system

et al. 2015

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A highly selective and robust method for simultaneous screening and confirmation of target and non-target phosphodiesterase type 5 (PDE-5) inhibitor analogues within a single chromatographic run in counterfeit herbal products was developed. The protocol, based on an easy and rapid extraction with a water/acetonitrile 1 % formic acid solution, followed by sonication and centrifugation, exploits an LC-diode array detector-quadrupole-time-of-flight (DAD-QTOF) system. The extraction method was optimized both at high concentrations and at trace levels. These two situations are typically encountered in pharmaceutical formulations and herbal food supplements. Carryover effects, never reported before and occurring mainly for vardenafil, were overcome using a polymer-based column. An in-house validation was carried out using five blanks of different bulk matrices spiked with seven standard analytes, namely yohimbine, sildenafil, vardenafil, tadalafil, homosildenafil, pseudovardenafil and hydroxyhomovardenafil. Reliable quantitation was possible using a conventional standard solution for all the pharmaceutical and herbal samples considered, as matrix effects were eliminated. Accuracy ranged from 80.9 to 108.1 % with overall relative standard deviation (RSD) <11 % (N = 15), measured at 1.0, 5.0 and 10.0 μg/g. Limits of detection (LODs) obtained ensured the determination of cross contaminations at nanogram per gram levels. A database with 82 PDE-5 inhibitor analogues was implemented for automatic non-target analysis. Among the 26 samples of dietary supplements and herbal remedies bulk marketed for erectile dysfunctions, three samples were found to be contaminated with both registered and unregistered synthetic PDE-5 inhibitors, i.e. yohimbine, sildenafil, dimethylsildenafil and thiodimethylsildenafil or thiomethisosildenafil. The occurrence of such contaminations, both at trace levels and at pharmaceutical dosage, indicates the illicit use of synthetic PDE-5 analogues. Graphical Abstract Examples of pharmaceutical formulations and herbal natural products marketed for the erectile dysfunction.

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“…The instrumental LOD computed according to Voigtman [31][32][33] with the KIO 3 standard was 23.6 AE 2.4 mg L À1 for iodine. Under these conditions the procedural LOD in the algae was 3.9 mg kg À1 (dry weight) for iodine, which is of the same order 12 or larger 17 than that obtained in previous studies.…”

Section: Limit Of Detectionmentioning

confidence: 99%

A procedure for the quantification of total iodine by inductively coupled plasma mass spectrometry, and its application to the determination of iodine in algae sampled in the lagoon of Venice

et al. 2016

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A procedure for the analysis of total iodine by inductively coupled plasma mass spectrometry (ICP-MS) is\ud proposed, in order to overcome the memory effects and recovery problems highlighted in the literature,\ud which are mainly due to the easy volatilization of iodine during the several analytical steps. The\ud microwave mineralization is performed in aqua regia. After dilution with water and before the injection\ud into the ICP-MS, the solution is added with 0.1 M NH4SCN. Suitable calibration conditions (KIO3 as the\ud iodine standard, 0.69% w/w HNO3 as the medium, and 0.1 M NH4SCN) were individuated. The\ud calibration sensitivity, recovery and limit of detection (LOD) were obtained. This procedure allowed the\ud simultaneous determination of most of the other elements usually analysed by ICP-MS, with the\ud exceptions of Ag, Ba, S, and partly also Pb. The procedure was then used to determine total iodine in\ud selected seaweed samples (Sargassum muticum (Harvey) Suringar, SM, and Undaria pinnatifida (Yendo)\ud Fensholt, UP) collected in six sites around Venice, where no iodine bio-monitoring has been hitherto\ud performed

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Estimation of the uncertainty of the quantification limit

Cited by 11 publications

References 10 publications

Long-distance connections in the Copper Age: New evidence from the Alpine Iceman’s copper axe

Long-distance connections in the Copper Age: New evidence from the Alpine Iceman’s copper axe

“One-shot” analysis of PDE-5 inhibitors and analogues in counterfeit herbal natural products using an LC-DAD-QTOF system

A procedure for the quantification of total iodine by inductively coupled plasma mass spectrometry, and its application to the determination of iodine in algae sampled in the lagoon of Venice

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