Determination of biogas process efficiency - a practice-oriented alternative to the biomethane potential test

2019 ◽  
Vol 7 ◽  
pp. 100201 ◽  
Author(s):  
René Casaretto ◽  
Fritz Thomsen ◽  
Jens Born ◽  
Jens Bo Holm-Nielsen
Keyword(s):  
Process Efficiency ◽  
Biomethane Potential ◽  
Biogas Process ◽  
Potential Test

LC–MS-MS Method for the Determination of Antidepressants and Benzodiazepines in Meconium

2020 ◽  
Vol 44 (6) ◽  
pp. 580-588
Author(s):  
A López-Rabuñal ◽  
E Lendoiro ◽  
M Concheiro ◽  
M López-Rivadulla ◽  
A Cruz ◽  
...  
Keyword(s):  
Extraction Efficiency ◽  
Solid Phase ◽  
Gradient Methods ◽  
Reversed Phase ◽  
Process Efficiency ◽  
Limit Of Quantification ◽  
Mode 2 ◽  
Positive Mode ◽  
Compound Method

Abstract An LC–MS-MS method for the determination of 14 benzodiazepines (BZDs) (alprazolam, α-hydroxyalprazolam, clonazepam, bromazepam, diazepam, nordiazepam, lorazepam, lormetazepam, oxazepam, flunitrazepam, 7-aminoflunitrazepam, triazolam, midazolam and zolpidem) and 15 antidepressants (ADs) (amitriptyline, nortriptyline, imipramine, desipramine, clomipramine, norclomipramine, fluoxetine, norfluoxetine, sertraline, norsertraline, paroxetine, venlafaxine, desmethylvenlafaxine, citalopram and desmethylcitalopram) in meconium was developed and validated. Meconium samples (0.25 ± 0.02 g) were homogenized in methanol and subjected to mixed-mode cation exchange solid-phase extraction. Chromatographic separation was performed in reversed phase, with a gradient of 0.1% formic acid in 2 mM ammonium formate and acetonitrile. Two different chromatographic gradient methods were employed, one for the separation of ADs and another for BZDs. Analytes were monitored by tandem mass spectrometry employing electrospray positive mode in MRM mode (2 transitions per compound). Method validation included: linearity [n = 5, limit of quantification (LOQ) to 400 ng/g], limits of detection (n = 6, 1–20 ng/g), LOQ (n = 9, 5–20 ng/g), selectivity (no endogenous or exogenous interferences), accuracy (n = 15, 90.6–111.5%), imprecision (n = 15, 0–14.6%), matrix effect (n = 10, −73 to 194.9%), extraction efficiency (n = 6, 35.9–91.2%), process efficiency (n = 6, 20.1–188.2%), stability 72 h in the autosampler (n = 3, −8.5 to 9%) and freeze/thaw stability (n = 3, −1.2 to −47%). The method was applied to four meconium specimens, which were analyzed with and without hydrolysis (enzymatic and alkaline). The authentic meconium samples tested positive for alprazolam, α-hydroxyalprazolam, clonazepam, diazepam, nordiazepam, fluoxetine, norfluoxetine, clomipramine and norclomipramine. Therefore, the present LC–MS-MS method allows a high throughput determination of the most common BZDs and ADs in meconium, which could be useful in clinical and forensic settings.

scholarly journals Application of Bar Adsorptive Microextraction for the Determination of Levels of Tricyclic Antidepressants in Urine Samples

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3101
Author(s):  
Mariana N. Oliveira ◽  
Oriana C. Gonçalves ◽  
Samir M. Ahmad ◽  
Jaderson K. Schneider ◽  
Laiza C. Krause ◽  
...  
Keyword(s):  
Tricyclic Antidepressants ◽  
Matrix Effects ◽  
Activated Carbons ◽  
Process Efficiency ◽  
Gas Chromatography Mass Spectrometry ◽  
Selected Ion Monitoring ◽  
Experimental Conditions ◽  
Analytical Methodology ◽  
Low Efficiency

This work entailed the development, optimization, validation, and application of a novel analytical approach, using the bar adsorptive microextraction technique (BAμE), for the determination of the six most common tricyclic antidepressants (TCAs; amitriptyline, mianserin, trimipramine, imipramine, mirtazapine and dosulepin) in urine matrices. To achieve this goal, we employed, for the first time, new generation microextraction devices coated with convenient sorbent phases, polymers and novel activated carbons prepared from biomaterial waste, in combination with large-volume-injection gas chromatography-mass spectrometry operating in selected-ion monitoring mode (LVI-GC-MS(SIM)). Preliminary assays on sorbent coatings, showed that the polymeric phases present a much more effective performance, as the tested biosorbents exhibited low efficiency for application in microextraction techniques. By using BAμE coated with C18 polymer, under optimized experimental conditions, the detection limits achieved for the six TCAs ranged from 0.2 to 1.6 μg L−1 and, weighted linear regressions resulted in remarkable linearity (r2 > 0.9960) between 10.0 and 1000.0 μg L−1. The developed analytical methodology (BAμE(C18)/LVI-GC-MS(SIM)) provided suitable matrix effects (90.2–112.9%, RSD ≤ 13.9%), high recovery yields (92.3–111.5%, RSD ≤ 12.3%) and a remarkable overall process efficiency (ranging from 84.9% to 124.3%, RSD ≤ 13.9%). The developed and validated methodology was successfully applied for screening the six TCAs in real urine matrices. The proposed analytical methodology proved to be an eco-user-friendly approach to monitor trace levels of TCAs in complex urine matrices and an outstanding analytical alternative in comparison with other microextraction-based techniques.

Determination of methane yield of cellulose using different experimental setups

2014 ◽  
Vol 70 (4) ◽  
pp. 599-604 ◽  
Author(s):  
Bing Wang ◽  
Ivo Achu Nges ◽  
Mihaela Nistor ◽  
Jing Liu
Keyword(s):  
Water Column ◽  
Test System ◽  
Methane Yield ◽  
Biochemical Methane Potential ◽  
Methane Potential ◽  
Bmp Test ◽  
Potential Test

In this work, biochemical methane potential (BMP) tests with cellulose as a model substrate were performed with the aid of three manually operated or conventional experimental setups (based on manometer, water column and gas bag) and one automated apparatus specially designed for analysis of BMP. The methane yields were 340 ± 18, 354 ± 13, 345 ± 15 and 366 ± 5 ml CH4/g VS obtained from experimental setups with manometer, water column, gas bag, and automatic methane potential test system, which corresponded to a biodegradability of 82, 85, 83 and 88% respectively. The results demonstrated that the methane yields of cellulose obtained from conventional and automatic experimental setups were comparable; however, the methane yield obtained from the automated apparatus showed greater precision. Moreover, conventional setups for the BMP test were more time- and labour-intensive compared with the automated apparatus.

scholarly journals Developing instrument of academic potential test analogy verbal ability for undergraduate students

2021 ◽  
Vol 15 (2) ◽  
pp. 234-241
Author(s):  
Efi Septianingsih ◽  
Mohammad Adam Jerusalem
Keyword(s):  
Undergraduate Students ◽  
Verbal Ability ◽  
Sampling Technique ◽  
Test Reliability ◽  
Bartlett’S Test ◽  
Verbal Analogies ◽  
Academic Potential ◽  
Potential Test

The paper aims to develop the instrument about analogy test to measure the level of intelligence of undergraduate students. Determination of the number of samples is done by purposive sampling technique. This instrument is analyzed by factor analysis. Of the 15 items that will be used to develop the academic potential test instrument for verbal analogies, 4 analysis factors. The formation of these 4 factors is from Eigenvalues greater than 1 so that there are only 4 factors that fulfill the requirements. Furthermore, 15 items of the tested instrument to 91 undergraduate student respondents obtained 2 items of invalid instrument with correlation coefficient ≤0.3, Kaiser-Meyer-Olkin (KMO) and Bartlett's test amounted to 0.785 with p 0.05. Trial results from the results of the trial results obtained that the average validity of the questions is 96.8%. Test reliability was analyzed using the Alpha (α) formula of Cronbach. The calculation is done using the help of the IBM SPSS version 22.0 Windows program and the coefficient of 0.806 is obtained. Based on the results of the research, it can be concluded that the quality of the developed instrument items has been valid and reliable.

Valorization of Arid Region Abattoir Animal Waste: Determination of Biomethane Potential

2018 ◽  
Vol 9 (12) ◽  
pp. 2327-2335
Author(s):  
Juan-Rodrigo Bastidas-Oyanedel ◽  
Akinleye Sowunmi ◽  
Jens Ejbye Schmidt
Keyword(s):  
Arid Region ◽  
Animal Waste ◽  
Biomethane Potential

scholarly journals Implementation of Fuzzy Tsukamoto Algorithm in Determining Work Feasibility

2017 ◽  
Author(s):  
Andysah Putera Utama Siahaan
Keyword(s):  
Grade Point Average ◽  
Fuzzy System ◽  
Membership Functions ◽  
Grade Point ◽  
The Difference ◽  
Parameter Values ◽  
Academic Potential ◽  
Potential Test

The process of determining eligibility for someone is usually given with the same value. The determination of eligibility is determined based on several criteria. These criteria are the ability to Academic Potential Test (APT) and Grade Point Average (GPA). The Tsukamoto fuzzy system is the model used in this paper. Each input variable is divided into two membership functions. There are nine rules of Tsukamoto's model applied. The system also provides following changes of parameters if the parameter values are to be changed. The result of the difference of the employability is given to them. The greater the APT score, the more the value of the feasibility of the work obtained. The more GPA values gained, the greater the value of the workplace eligibility.

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