High-Throughput Analytical Techniques for Multiresidue, Multiclass Determination of 653 Pesticides and Chemical Pollutants in Tea—Part III: Evaluation of the Cleanup Efficiency of an SPE Cartridge Newly Developed for Multiresidues in Tea

2013 ◽  
Vol 96 (4) ◽  
pp. 887-896 ◽  
Author(s):  
Guo-Fang Pang ◽  
Chun-Lin Fan ◽  
Qiao-Ying Chang ◽  
Yan Li ◽  
Jian Kang ◽  
...  
Keyword(s):  
Comparative Study ◽  
Green Tea ◽  
Residue Analysis ◽  
Analytical Techniques ◽  
Test Results ◽  
Cleanup Efficiency ◽  
Three Samples ◽  
Primary Secondary Amine ◽  
The Comparative Study

Abstract A comparative study was conducted over three stages on the cleanup efficiency of SPE cartridge Cleanert TPT, newly developed for multigroups of pesticide residues in tea. In Stage I, different SPE cartridges C18, graphite carbon black (GCB), primary secondary amine (PSA), and amino (NH2) were purchased and combined into 12 different sequences. Through the comparative test on cleanup efficiency of 84 representative pesticides in tea, Envi-Carb GCB + PSA with a good cleanup effect was selected. In Stage II, GC/MS test results from the comparative study of the extraction efficiency of 201 pesticides spiked into green tea and Woolong tea with Cleanert TPT and Envi-Carb + PSA SPE showed that average recoveries fell within 70–110% and RSD <20% for 193 and 184 pesticides, respectively, for green tea, accounting for 96.0 and 91.0% of the total number, respectively. GC/MS/MS test results also found 193 and 184 pesticides, respectively, meeting the recovery and RSD conditions, accounting for 96.0 and 91.5%, respectively, of the total number. For Woolong tea samples, GC/MS results showed that with Cleanert TPT and Envi-Carb + PSA SPE for cleanup, there were 192 and 177 pesticides, respectively, meeting the conditions, accounting for 95.5 and 88.1% of the total number, respectively. GC/MS/MS results demonstrated that there were 195 and 184 pesticides, respectively, meeting the conditions, accounting for 97.0 and 91.5% of the total number, respectively. It was seen that Cleanert TPT was superior to Envi-Carb + PSA in cleanup efficiency, whether for green or Woolong tea samples, or GC/MS or GC/MS/MS determination. In Stage III, 61 104 results of the average content value of pesticides and RSD (two teas × two Youden pair concentrations × two kinds of SPE cartridges × two instruments × 19 tests × 201 pesticides) were derived from the 19 times stability tests over 3 months by paralleling three samples every 5 days via two instruments with two kinds of SPE cartridges for cleanup, respectively, against Youden Pair samples of the 201 incurred pesticides from green and Woolong teas. The statistical analysis found that detected values from the target pesticides of the incurred Youden pair samples showed no marked differences with cleanup by either Cleanert TPT or Envi-Carb + PSA, whether for green or Woolong tea, or GC/MS or GC/MS/MS. The test results using the two aforementioned kinds of SPE cleanup for above 93% pesticides had a tolerance less than 15%, which testifies that both cartridge cleanups met the requirement for pesticide residue analysis.

High-Throughput Analytical Techniques for Multiresidue, Multiclass Determination of 653 Pesticides and Chemical Pollutants in Tea–Part IV: Evaluation of the Ruggedness of the Method, Error Analysis, and Key Control Points of the Method

2015 ◽  
Vol 98 (1) ◽  
pp. 130-148 ◽  
Author(s):  
Chun-Lin Fan ◽  
Yan Li ◽  
Qiao-Ying Chang ◽  
Guo-Fang Pang ◽  
Jian Kang ◽  
...  
Keyword(s):  
Green Tea ◽  
High Throughput ◽  
Analytical Techniques ◽  
Control Points ◽  
Method Error ◽  
Chemical Pollutants ◽  
Primary Secondary Amine ◽  
Accuracy And Stability ◽  
Better Than

Abstract A 3 month study was conducted on the ruggedness of a multiresidue method for accuracy and stability. The results indicate that in terms of Youden pair ratios of 201 pesticide aged tea samples falling approximately within 1.00–1.20 of the ratio of theoretical spraying concentrations, the differences donot exceed 5% for percentages made up by ratios of the fixed values obtained by two kinds of instrumentsfor two teas and those made up by 18 circular determinations. However, regarding two kinds of SPE cartridges, the Cleanert TPT cartridgeis higher than the ENVI-CARB + primary secondary amine (PSA) cartridge by 10%. Pertaining to RSD values of “parallelsamples” and whether it is green tea or Woolong tea, the percentages of RSD ≤15% values ofthe parallel samples all exceed 88%. Whether it isthefirst or circular determination for two teas andanalytical results from two kinds of instruments, the percentages of RSD ≤15% values have a difference of less than 6%, while the TPT cartridge is betterthan ENVI-CARB + PSA by above 6% for the two cartridges. Concerning RSDs of Youden pair ratios, RSD ≤15% values have a proportion exceeding 85% for both green tea and Woolong tea, and the percentageis greater than 87% whether it is for two kinds of SPE cartridges or two kinds of instruments. In terms of Youden pair ratios and the classified statisticalanalysis of the ruggedness data of parallel samples,theproportion of RSD ≤15% values of Youden pair ratios is 8% higher for the TPT cartridge than the ENVI-CARB + PSA cartridge; the proportion of RSD ≤15% values of parallel samples is 6.2% higher for the TPT cartridge than the ENVI-CARB + PSA cartridge. Data show no marked differences for two teas and two kinds of instruments. A comparison of the aforementioned aspects finds that good ruggedness was obtained with both SPE cleanup methods, and the results from the TPT cartridge are better than those from the ENVI-CARB + PSA cartridge.

High-Throughput Analytical Techniques for Determination of Residues of 653 Multiclass Pesticides and Chemical Pollutants in Tea, Part II: Comparative Study of Extraction Efficiencies of Three Sample Preparation Techniques

2013 ◽  
Vol 96 (2) ◽  
pp. 432-440 ◽  
Author(s):  
Chun-Lin Fan ◽  
Qiao-Ying Chang ◽  
Guo-Fang Pang ◽  
Zeng-Yin Li ◽  
Jian Kang ◽  
...  
Keyword(s):  
Sample Preparation ◽  
Green Tea ◽  
High Speed ◽  
Extraction Efficiency ◽  
Preparation Technique ◽  
Test Results ◽  
Chemical Pollutants ◽  
Chemical Pollutant ◽  
Three Stages

Abstract This paper reports a study of the extraction efficiency for the multiresidue pesticides and chemical pollutants in tea with three methods over three stages. Method 1 adopts the Pang et al. approach: the targets were extracted with 1% acetic acid in acetonitrile and cleaned up with a Cleanert TPT SPE cartridge; Method 2 adopts the QuEChERS approach: the targets were cleaned up dispersively with graphitized carbon and primary-secondary amine (PSA) sorbent; Method 3 adopts the relatively commonly used approach of hydration for solid samples, with tea hydrated before being extracted through salting out with acetonitrile and the cleanup procedures identical to those of Method 1. The three stages comprised two phases of comparative tests on spike recoveries of 201 pesticides and chemical pollutants from different teas and a third phase on determination of the content of the 201 pesticides and chemical pollutants from aged tea samples. In stages I and II, test results of the spike recoveries of 201 pesticides and chemical pollutants demonstrated that 91.4% of the pesticide and chemical pollutant recoveries fell within the range of 70–110%, and 93.2% of the pesticides and chemical pollutants had RSD < 15%, with no marked difference obtained by Method 1 and Method 2 regardless of whether it was green tea or woolong tea, or GC/MS or GC/MS/MS was used for analysis. For pigment removal, Method 1 was superior to Method 2; in terms of easy operation, Method 2 outweighed Method 1. However, Method 3 obtained relatively low recoveries, with 94% of pesticide and chemical pollutant recoveries less than 70%, which proved that Method 3 was not applicable to the determination of multiresidue pesticides and chemical pollutants in tea. Stage III made a comparison of Method 1 and Method 2 for the extraction efficiency of pesticides and chemical pollutants in 165-day-aged samples of green and woolong tea. Test results showed that 94% of the pesticide and chemical pollutant content in the aged tea samples was recovered with Method 1, more than 10% higher than with Method 2 (30–50% higher on average). For green tea, 193 (GC/MS/MS) and 197 (GC/MS) pesticides and chemical pollutants accounted for 96.5% (GC/MS/MS) and 98.0% (GC/MS) with Method 1 higher than with Method 2. For woolong tea, 191 (GC/MS/MS) and 194 (GC/MS) pesticides and chemical pollutants accounted for 95% (GC/MS/MS) and 96% (GC/MS/MS) with Method 1, higher than with Method 2, respectively. In other words, there were definite differences in the test results for aged tea samples between Method 1 and Method 2, which suggests that Method 1 was capable of extracting more residual pesticides and chemical pollutants from the precipitated 165-day-aged tea samples. The reason can be traced to the possibility that Method 1 (high-speed homogenizing) has better extraction efficiency than Method 2 (vortex and oscillation). Therefore, Method 1 was chosen as the sample preparation technique for multiresidue pesticide and chemical pollutant analysis in tea.

scholarly journals Comparative Study of Calculation Models for the Fire Resistance of Hollow Steel Columns Filled with Concrete

2020 ◽  
Author(s):  
Farid Fellah
Keyword(s):  
Comparative Study ◽  
Computer Program ◽  
Fire Resistance ◽  
Applied Load ◽  
Computer Code ◽  
Test Results ◽  
Calculation Methods ◽  
Steel Columns ◽  
Design Engineers ◽  
The Comparative Study

Various calculation methods are proposed in codes for the evaluation of fire resistance of hollow steel columns filled with concrete, but the use of some of them may be very tedious for design engineers, and it may be interesting to have more practical tools at their disposal. In the comparative study presented here, three methods based on different procedures are investigated. Kodur’s method is a set of formulas allowing to calculate the fire resistance or the maximum applied load. Potfire is a computer program for which a user’s manual is provided and clean instructions describe how to introduce the data. SAFIR is a non-linear computer code that can simulate the behavior of structures under fire conditions. Comparisons are made between the results obtained by the three methods and test results. The differences are analyzed, and the influence of some parameters is examined. From the results obtained in this comparative study, it is possible to say in which cases each method can be used.

scholarly journals DETERMINATION OF THE WAVE ATTACK ANTICIPATED UPON A STRUCTURE FROM LABORATORY AND FIELD OBSERVATIONS

2011 ◽  
Vol 1 (7) ◽  
pp. 37
Author(s):  
W.A. Venis
Keyword(s):  
Comparative Study ◽  
Model Tests ◽  
Water Levels ◽  
Field Observations ◽  
Wave Impact ◽  
Spring System ◽  
Mass Spring ◽  
The Comparative Study ◽  
The Impact

Model tests have been carried out to obtain an insight into the magnitude of the wave-pressures in various situations. These tests showed, that sharp high pressure peaks occur in addition to the pressures caused by the reflecting of the waves, which pressures are quasi-static. As the structure can be compared with a multiple mass-spring system these pressure-peaks may cause the whole construction to vibrate. Wave-attack therefore can be expressed in terms of impact. Moreover, calculations revealed that the impact pressures were critical factors in determining the strength of the structure. So many model tests were carried out to determine the design and location of the sluices. These tests involved numerous water-levels discharges and waves. Regarding the pressure-peaks a comparative study was made in the model, which led to the structure being designed in such a way that the occurrence of critical impacts was reduced to an acceptable minimum. As it was impossible to avoid the occurrence of impact pressures entirely it remained necessary to determine a basic load for the structure that takes care of the impact pressures. As it has not yet appeared possible physically to determine a theoretical maximum for the impact pressures, it has to be borne in mind that there is a probability that each pressure measured will be exceeded. So this paper describes, how the cumulative frequency curve of the impacts for the case mentioned in 1.1 sub a, which served as a basis for determining the basic load was arrived at by a certain combination of laboratory and field observations. The data used for this purpose were a. Results of wave-impact measurements on a model of the sluices. This model, built in accordance with the results of the comparative study, was situated in the wind-flume of the "de Voorst" hydraulic laboratory. b. Wave height measurements in the Haringvliet during 1957 and 1958. c. Wind-speed measurements on board the lightship Qoeree, likewise during 1957 and 1958. d. Tidal registrations at Hellevoetsluis from 1920 to 1960. e. Wind-force data from the Hook of Holland, likewise from 1920 to 1960.

scholarly journals Symbolism in the English and Russian fairy tale folklore: comparative analysis

2021 ◽  
pp. 94-106
Author(s):  
Kseniya Yur'evna Vavilova
Keyword(s):  
Comparative Analysis ◽  
Comparative Study ◽  
Fairy Tales ◽  
Fairy Tale ◽  
Time And Space ◽  
The Subject ◽  
The Comparative Study

The subject of this research is the symbolism in the English and Russian fairytale tradition. The object is the texts of the Russian and English fairy tales. Analysis of the texts reveals the typical functions performed by symbols in both folklore traditions. The author provides the examples of symbols and offers the interpretation of objects-symbols, symbols-zoonyms, color and number symbols, time and space symbols. Comparative study of folklore heritage of non-cognate languages reveals the fundamental commonness of a particular folk genre of different peoples in their perspective upon reality, methods of depiction, and ideological interpretations. The scientific novelty consists in conclusions obtained in the comparative study of the symbolism of fairy tale texts in the Russian and British folklore, which is important for determination of linguistic, semiological and cultural universals. The comparative study of folklore material of two traditions in the sphere of the poetics of folklore reveals the traditional universals and unique features on the level of symbolism of the fairy tale genre. Within the framework of the article, the author analyzes the functionality of thematic, animalistic, color, spatial-temporal, and numerical symbols. The acquired results are underpinned by a large number of text examples.

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