Optimising uncertainty in physical sample preparation

Lyn, Jennifer A.; Damant, Andrew; Wood, Roger

doi:10.1039/b506278k

Cited by 6 publications

(3 citation statements)

References 12 publications

(29 reference statements)

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“…Twenty separate sources were identified, including references cited above 8,9,12,15 and a further sixteen sources [24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39] . to be important food contaminants, present at low levels and prone to high sampling variance, so many of the larger studies -though not the majority of analyte/product combinations -had focused on mycotoxins in granular products such as grain, nuts, or green coffee.…”

Section: Literature Survey Of Sampling Uncertainty In Food Analysismentioning

confidence: 99%

Is measurement uncertainty from sampling related to analyte concentration?

Ellison¹,

Lawrance²,

Stuart³

et al. 2017

Anal. Methods

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The contribution of sampling to the combined uncertainty of measurement is assessed using a combination of literature review and experimental determination of sampling variability in a range of foodstuffs in order to determine whether there is a consistent relationship between analyte level and proportion of variation attributable to sampling. Experimental determinations used the duplicate method, an economical method of assessing the relative contributions of sampling and analytical variability to the overall variance of results. The experimental work covered sampling of retail foodstuffs. 101 estimates of between-target, between-sampling,and within-sample variance were obtained. It is shown for the first time that sampling variance across the food sector appears to follow a Horwitz-like relationship sufficient to provide estimated between-sample standard deviation to within approximately an order of magnitude. The results from different methods of data processing for sampling uncertainty experiments are also compared. It is shown that for the data sets obtained experimentally in this study, log-transformation is of minor importance while the use of robust statistical methods can have greater but less predictable effects on estimated sampling variance.2

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Section: Literature Survey Of Sampling Uncertainty In Food Analysismentioning

confidence: 99%

Is measurement uncertainty from sampling related to analyte concentration?

Ellison¹,

Lawrance²,

Stuart³

et al. 2017

Anal. Methods

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“…Sample preparation is crucial to ensure proper pre-treatment for chemical analysis in various biomedical applications. 1,2 One of the most important parts of the process is the particle separation in which groups different particles in a certain environment are separated according to their characteristics, such as size, mass, and charge. [3][4][5] Particle separation can minimize unexpected biomolecular and chemical interactions, which prevents distorted analysis and diagnosis.…”

Section: Introductionmentioning

confidence: 99%

A low sample volume particle separation device with electrokinetic pumping based on circular travelling-wave electroosmosis

Lin

Sung

et al. 2013

Lab Chip

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Particle separation is a crucial step in sample preparation processes. The preparation of low volume samples is especially important for clinical diagnosis and chemical analysis. The advantages of microfluidic techniques have lead them to become potential candidates for particle separation. However, existing microfluidic devices require external pumping sources and extensive geometric patterns to attain high separation efficiency, which is disadvantageous when handling low volume samples. This paper presents a low sample volume particle separation microfluidic device with low voltage electrokinetic pumping based on circular travelling-wave electroosmosis (TWEO). Computational numerical software was utilized to simulate two electrokinetic mechanisms: circular TWEO and dielectrophoresis (DEP). The circular TWEO shear flow generates a velocity gradient in the radial direction which causes a shear stress-induced force to drag particles into the center region of the device. In contrast, the non-parallel electrodes induce negative DEP forces which push polystyrene beads towards the peripheral regions; the magnitude of the DEP forces are dependent on the sizes of the polystyrene beads. We used particles of various sizes to experimentally prove the concept of particle separation. Our experiments show that 15 μm beads are dragged into the center region due to the shear stress-induced force, and 1 μm beads move towards the outer region because of the large negative DEP force. The results show a separation purity of 94.4% and 80.0% for 15 μm and 1 μm beads respectively. We further demonstrated particle isolation from a sample of containing a small proportion of 6 μm beads mixed with 1 μm beads at a concentration ratio of 1 : 300. Therefore, the innovative device developed in this paper provides a promising solution to allow particle separation in sample volumes as low as 50 nL.

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“…Sample pretreatment plays an important role in the whole process of analysis, which is time-consuming and is the main source of errors during analysis. − Solid-phase extraction (SPE) is one of the common methods in the sample pretreatment, widely applied in the fields of environment, food, biology, and medicine . The solid materials can be used to extract the analytes from the complex sample, and then the extracted analytes can be eluted using solvents with more affinity to analytes.…”

mentioning

confidence: 99%

Microorganisms as Bio-SPE Materials for Extraction of Pharmaceutical Drugs: Mechanism of Extraction

Liu

Wang

et al. 2021

Anal. Chem.

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In solid-phase extraction (SPE), the extraction materials depend on the physicochemical interactions to obtain the target analytes from complex systems. However, many matrix interferences existing in real samples influence the extraction efficiency through these common interactions. Therefore, extraction materials based on more special interactions for biological systems need to be developed. In this work, live microorganisms including Escherichia coli and Staphylococcus aureus were considered as the potential biological SPE (bio-SPE) materials with their biological functions in the live state. To study the enrichment and selectivity of the bio-SPE, four antibacterial drugs and two non-antibacterial drugs were employed as the target analytes. The enrichment factor (EF) was used as the evaluation index. The results showed that when using chlorpheniramine (CPM) and ofloxacin (OFLO), the enrichment capacity of E. coli was better than that of S. aureus. When extracting a single analyte, the enrichment ability of E. coli for CPM was significantly higher than other analytes, and the EF was 8.5. In a mixture solution of antibacterial analytes, OFLO could be enriched mostly by E. coli. However, in the mixture solution of antibacterial and non-antibacterial analytes, CPM was enriched more than that of antibacterial analytes. In real rat plasma, bio-SPE using live E. coli could obviously extract CPM, while traditional liquid− liquid extraction could not. The confocal microscopy results showed that the extraction mechanism may not only depend on the surface adsorption of bacteria with analytes but also on the uptake into bacteria. This provides a valuable basis for the development of more biological separation materials based on biological interactions.

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Optimising uncertainty in physical sample preparation

Cited by 6 publications

References 12 publications

Is measurement uncertainty from sampling related to analyte concentration?

Is measurement uncertainty from sampling related to analyte concentration?

A low sample volume particle separation device with electrokinetic pumping based on circular travelling-wave electroosmosis

Microorganisms as Bio-SPE Materials for Extraction of Pharmaceutical Drugs: Mechanism of Extraction

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