Handling Multiple Method Detection Limit Estimates: Which Statistical Estimate Should Be Reported?

2019 ◽  
pp. 105-116
Author(s):  
Thomas J. Bzik
Keyword(s):  
Detection Limit ◽  
Statistical Estimate ◽  
Method Detection Limit ◽  
Multiple Method

scholarly journals RISIKO KESEHATAN PAJANAN BENZENA, TOLUENA DAN XYLENA PETUGAS PINTU TOL

2016 ◽  
Vol 11 (2) ◽  
pp. 188 ◽  
Author(s):  
Bambang Wispriyono ◽  
Eko Handoyo
Keyword(s):  
Detection Limit ◽  
Health Risks ◽  
Risk Groups ◽  
Health Impacts ◽  
Method Detection Limit ◽  
Cross Sectional ◽  
Risk Management System ◽  
Environmental Health Risk ◽  
Benzene Concentration ◽  
Benzene Toluene

<p>Efek negatif dari polusi udara terhadap kesehatan manusia banyak diteliti termasuk polusi akibat sistem transportasi. Emisi kendaraan bermotor menghasilkan Benzena, Toluena dan Xylena (BTX) yang merupakan bahan kimia yang bersifat karsinogenik dan petugas pintu tol merupakan kelompok berisiko terpajan BTX. Penelitian bertujuan mengetahui risiko kesehatan akibat pajanan BTX pada petugas pintu tol. Desain penelitian adalah <em>cross-sectional</em> dengan pendekatan Analisis Risiko Kesehatan Lingkungan (ARKL) dan  faktor-faktor antropometri. Hasil penelitian menunjukkan pada pintu tol rata-rata konsentrasi (mean<span style="text-decoration: underline;">+</span>SD) benzena sebesar 0,00167<span style="text-decoration: underline;">+</span>0,000056 mg/m<sup>3</sup>, toluena sebesar 0,00124<span style="text-decoration: underline;">+</span>0.000049 mg/m<sup>3</sup> dan xylena sebesar 0,00147<span style="text-decoration: underline;">+</span>0,000063 mg/m<sup>3</sup> sedangkan pada kantor administrasi konsentrasi tidak terdeteksi oleh alat (<em>Method Detection Limit</em>). Rata-rata risiko non karsinogenik (RQ) BTX pada petugas pintu tol lebih tinggi secara signifikan dibandingkan dengan rata-rata RQ BTX petugas administrasi. Risiko kesehatan non karsinogenik dan karsinogenik belum menunjukkan adanya risiko kesehatan yang signifikan. Upaya pencegahan berupa pengelolaan manajemen risiko untuk pengendalian risiko bahan berbahaya di lingkungan perlu ditingkatkan.</p><p> </p><p><strong>Kata Kunci:</strong> Pintu Tol, Benzena, Toulena, Xylena</p><p> </p><p>The researches of BTX (Benzene, Toluene and Xylene) related to the health impacts have been done and published in any publications. One of the risk groups is toll gate’s workers who have been exposed every day with BTX. The design of this study is cross-sectional with Environmental Health Risk Analysis to determine the magnitude of health risks of BTX on the toll gate. The results showed at the toll workers’s respondents have  benzene concentration 0.00167+0.000056 mg/m<sup>3</sup>, toluene 0.00124+0.000049 mg/m<sup>3</sup> and xylene 0.00147+0,000063 mg/m<sup>3</sup> respectively, while in the administrative office’s respondents, BTX was undetectable (Minimum Detection Limit). The average RQ of toll gate respondents was significantly higher than administrative office’s respondents. In conclusion, the risk of all workers have the RQ ≤ 1. Non carcinogenic and carcinogenic health risks to all toll gate’s workers recently have not shown any risk yet. Nevertheless, risk management system should be developed and improved.</p><p> </p><p><strong>Keywords</strong>: Toll Gate, Benzene, Toulene, Xylene</p>

Graphite Furnace Atomic Absorption Method for the Determination of Lead in Sugars and Syrups

1994 ◽  
Vol 77 (5) ◽  
pp. 1288-1292 ◽  
Author(s):  
Nancy J Miller-Ihli
Keyword(s):  
Detection Limit ◽  
Atomic Absorption ◽  
Graphite Furnace ◽  
Absorption Spectrometry ◽  
Magnesium Nitrate ◽  
Method Detection Limit ◽  
High Fructose ◽  
Graphite Furnace Atomic Absorption ◽  
Characteristic Mass

Abstract A method was developed for the determination of lead in sugars and syrups. Samples are wet-ashed with a nitric acid–hydrogen peroxide procedure and analyzed by graphite furnace atomic absorption spectrometry. The method involves the use of magnesium nitrate as a matrix modifier, air ashing, platform atomization, and quantitation by peak area measurements with direct calibration against aqueous standards. The instrumental detection limit (based on 3.29σ) was 10 pg, or 0.5 μg/L for a 20 μL injection, corresponding to a method detection limit of 3.3 ng/g sugar. The characteristic mass was approximately 12 pg. This method was validated by analyzing sucrose and high-fructose corn syrup samples spiked with known quantities of lead. The average recovery was 101 ± 6%.

A Survey of Benzene in Fruits and Retail Fruit Juices,Fruit Drinks, and Soft Drinks

1992 ◽  
Vol 75 (2) ◽  
pp. 334-340 ◽  
Author(s):  
Denis B Page, ◽  
Henry B.S Conacher, ◽  
Dorcas Weber, ◽  
Gladys Lacroix,
Keyword(s):  
Gas Chromatography ◽  
Detection Limit ◽  
Capillary Gas Chromatography ◽  
Soft Drinks ◽  
Fruit Juices ◽  
Mineral Waters ◽  
Headspace Sampling ◽  
Method Detection Limit ◽  
Selected Ion Monitoring ◽  
Full Scan

Abstract Recent findings of benzene In several fruit-flavored mineral waters at low μg/kg levels, reportedly arising from added benzoate, have prompted a survey of various fruits, juices, and drinks for traces of benzene. Headspace sampling, capillary gas chromatography, and mass spectrometrlc detection enabled detection with confirmation (full-scan spectrum) of benzene as low as 0.03 μg/kg. With selected Ion monitoring, the method detection limit was 0.02 μg/kg, I.e., 3 times the analytical blank, in total, 97 samples were analyzed. Benzene was found at levels ranging from 0.018 to 3.83 μg/kg. Samples labeled to contain added benzoate or believed to contain natural benzoate, such as cranberries, were found to contain benzene at higher levels (n = 41, av. 0.66 μg/kg) than other samples (n = 32, av. 0.082 μg/kg). Average levels of benzene In fruits (as expressed juice), In juices with and without benzoate, In noncarbonated drinks with and without benzoate, and in soft drinks with and without benzoate were 0.042,0.672,0.056,0.395, 0.116,0.793, and 0.062 μg/kg, respectively

scholarly journals Monitoring of cyanobacteria using derivative spectrophotometry and improvement of the method detection limit by changing pathlength

2021 ◽  
Author(s):  
Amitesh Malhotra ◽  
Banu Örmeci
Keyword(s):  
Detection Limit ◽  
Derivative Spectrophotometry ◽  
Method Detection Limit ◽  
Toxigenic Strain ◽  
Adverse Health Effects ◽  
First Derivative ◽  
Monitoring Tools ◽  
Wide Range ◽  
Low Probability ◽  
Who Guideline

Abstract Effective monitoring tools and methods are needed for the early detection and management of cyanobacteria in water bodies to minimize their harmful impacts on the environment and public health. This research investigated changing the cuvette pathlength (10-, 50-, and 100-mm) to improve the detection of cyanobacteria using UV-Vis spectrophotometry with subsequent application of derivative spectrophotometry and Savitzky-Golay (S-G) transformation. A non-toxigenic strain of blue-green cyanobacteria, Microcystis aeruginosa (CPCC 632), and a green algae strain for comparison, Chlorella vulgaris (CPCC 90), were studied in a wide range of concentrations (955,000–1,855 cells/mL). In each concentration range, method detection limits were established with absorbance measurements and S-G first derivative of absorbance using 10-, 50-, and 100-mm cuvette pathlengths. Increasing the cuvette pathlength from 10 to 100 mm resulted in a 15-fold improvement in sensitivity with absorbance and a 13-fold improvement with S-G first derivative of absorbance for M. aeruginosa. Overall, adoption of 100 mm pathlength and application of S-G derivative spectra improved the method detection limit for M. aeruginosa from 337,398 cells/mL to 4,916 cells/mL, which is below the WHO guideline for low probability of adverse health effects (&lt;20,000 cells/mL). Similarly, the detection limit for C. vulgaris was improved from 650,414 cells/mL to 11,661 cells/mL. The results also showed that spectrophotometry could differentiate M. aeruginosa from C. vulgaris based on the variations in their pigment absorbance peaks.

scholarly journals Simple and Fast Methods Based on Solid-Phase Extraction Coupled to Liquid Chromatography with UV Detection for the Monitoring of Caffeine in Natural, and Wastewater as Marker of Anthropogenic Impact

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Sònia Moret ◽  
Manuela Hidalgo ◽  
Juan M. Sanchez
Keyword(s):  
Detection Limit ◽  
Solid Phase Extraction ◽  
Natural Waters ◽  
Wastewater Treatment Plants ◽  
Solid Phase ◽  
Sample Volume ◽  
Uv Detection ◽  
Phase Extraction ◽  
Method Detection Limit ◽  
Spe Method

Two concentration methods for fast and routine determination of caffeine (using HPLC-UV detection) in surface, and wastewater are evaluated. Both methods are based on solid-phase extraction (SPE) concentration with octadecyl silica sorbents. A common “offline” SPE procedure shows that quantitative recovery of caffeine is obtained with 2 mL of an elution mixture solvent methanol-water containing at least 60% methanol. The method detection limit is 0.1 μg L−1 when percolating 1 L samples through the cartridge. The development of an “online” SPE method based on a mini-SPE column, containing 100 mg of the same sorbent, directly connected to the HPLC system allows the method detection limit to be decreased to 10 ng L−1 with a sample volume of 100 mL. The “offline” SPE method is applied to the analysis of caffeine in wastewater samples, whereas the “on-line” method is used for analysis in natural waters from streams receiving significant water intakes from local wastewater treatment plants.

In Vitro Degradation of Medical Polyacrylamide Hydrogel I.Oxidation

2005 ◽  
Vol 288-289 ◽  
pp. 397-400 ◽  
Author(s):  
Zi Yi Wan ◽  
Ting Fei Xi ◽  
P. Zhao ◽  
Cheng Xiang Fan ◽  
Y. Sun ◽  
...  
Keyword(s):  
Detection Limit ◽  
Hydroxyl Radical ◽  
Aesthetic Surgery ◽  
Hplc Method ◽  
Polyacrylamide Hydrogel ◽  
Method Detection Limit ◽  
In Vitro Degradation

Polyacrylamide (PAM) was usually atoxic, stable. Its hydrogel (PAMG) has been used in plastic and aesthetic surgery more than 10 years in P.R.China, Ukraine and Russia. But there were some complications with PAMG injected in patients. Considering the complicacy in vivo, it was necessary to study the PAMG’s stability. In this paper, H2O2 was added in PAMG in vitro and acrylamide (AM) content after oxidating was determined using HPLC method. Detection limit for AM can be achieved in the parts-per-billion rang. The AM content in supernatant at 0.5, 1,2 and 3 hr after oxidating of PAMG was 1.27e-8g/ml, 1.35e-8g/ml, 1.03e-7g/ml and 2.74e-7g/ml, respectively. The AM content in supernatant of PAMG was 7.70e-9g/ml. These results indicated that PAMG can be degraded to AM by hydroxyl radical. Under the same condition, the AM content was stable. So, AM can exist for a while when it was produce by degrading of PAMG. That can increase the toxicity of PAMG.

Determination of Folate in Infant Formula and Adult/Pediatric Nutritional Formula by Optical Biosensor Assay: First Action 2011.05

2012 ◽  
Vol 95 (2) ◽  
pp. 298-300 ◽  
Author(s):  
Harvey Indyk Fonterra ◽  
Dawn Dowell
Keyword(s):  
Detection Limit ◽  
Infant Formula ◽  
Binding Protein ◽  
Optical Biosensor ◽  
Sensor Surface ◽  
Method Detection Limit ◽  
Folate Binding Protein ◽  
Automated Assay ◽  
Single Laboratory

Abstract After a review of data from a single-laboratory validation (SLV) study published in the International Dairy Journal 21, 783–789 (2011), a method for folate in infant formula and adult/pediatric nutritional formula was submitted for consideration of adoption by AOAC as an automated assay that is rapid and simple. The method uses an optical biosensor assay to quantitate total folate content in milk and milk-based pediatric and adult nutritional products. The assay uses folate binding protein and a functionalized sensor surface. The SLV showed an instrumental LOD of 0.1 ng/mL (equivalent to 2.5 μg/100 g for a typical infant formula). The method detection limit was 6.5 μg/100 g with a repeatability of 3.48% and an intermediate reproducibility of 4.63% RSD.

scholarly journals A Modifiedo-Phthalaldehyde Fluorometric Analytical Method for Ultratrace Ammonium in Natural Waters Using EDTA-NaOH as Buffer

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Hongzhi Hu ◽  
Ying Liang ◽  
Shuo Li ◽  
Qing Guo ◽  
Chancui Wu
Keyword(s):  
Reaction Time ◽  
Detection Limit ◽  
Analytical Method ◽  
Natural Waters ◽  
Reagent Concentration ◽  
Method Detection Limit ◽  
Experimental Parameters ◽  
Ph Range ◽  
Optimal Ph ◽  
Disodium Ethylenediaminetetraacetate

In the existence of appropriate amount of disodium ethylenediaminetetraacetate (EDTA), precipitation would not occur in seawater and other natural waters even if the sample solution was adjusted to strong basicity, and the NH3-OPA-sulfite reaction at the optimal pH range could be used to determine ammonium in natural waters. Based on this, a modifiedo-phthalaldehyde fluorometric analytical method has been established to determine ultratrace ammonium in natural waters. Experimental parameters, including reagent concentration, pH, reaction time, and effect of EDTA, were optimized throughout the experiments based on univariate experimental design. The results showed that the optimal pH range was between 10.80 and 11.70. EDTA did not obviously affect the fluorometric intensity. The linearity range of the proposed method was 0.032–0.500 µmol/L, 0.250–3.00 µmol/L, and 1.00–20.0 µmol/L at the excitation/emission slit of 3 nm/5 nm, 3 nm/3 nm, and 1.5 nm/1.5 nm, respectively. The method detection limit was 0.0099 µmol/L. Compared to the classical OPA method, the proposed method had the advantage of being more sensitive and could quantify ultratrace ammonium without enrichment.

Method Detection Limit Determination and Application of a Convenient Headspace Analysis Method for Methyltert-Butyl Ether in Water

2002 ◽  
Vol 74 (22) ◽  
pp. 5907-5911 ◽  
Author(s):  
Dennis T. O'Neill ◽  
Elizabeth A. Rochette ◽  
Philip J. Ramsey
Keyword(s):  
Detection Limit ◽  
Headspace Analysis ◽  
Analysis Method ◽  
Method Detection Limit ◽  
Butyl Ether

A method detection limit for potentialin vivoarsenic measurements with a 50 W x-ray tube

2006 ◽  
Vol 51 (21) ◽  
pp. N381-N387 ◽  
Author(s):  
Ryan C N Studinski ◽  
Fiona E McNeill ◽  
Joanne M O'Meara ◽  
David R Chettle
Keyword(s):  
Detection Limit ◽  
Method Detection Limit ◽  
X Ray
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