Rinse Solution Research Articles

Lowering the transmission and spread of human coronavirus.

The emergence of the severe acute respiratory syndrome coronavirus 2 pandemic has created an unprecedented healthcare, social, and economic disaster. Wearing of masks and social distancing can significantly decrease transmission and spread, however, due to circumstances such as medical or dental intervention and personal choice these practices have not been universally adopted. Additional strategies are required to lessen transmission. Nasal rinses and mouthwashes, which directly impact the major sites of reception and transmission of human coronaviruses (HCoV), may provide an additional level of protection against the virus. Common over-the-counter nasal rinses and mouthwashes/gargles were tested for their ability to inactivate high concentrations of HCoV using contact times of 30 s, 1 min, and 2 min. Reductions in titers were measured by using the tissue culture infectious dose 50 (TCID50 ) assay. A 1% baby shampoo nasal rinse solution inactivated HCoV greater than 99.9% with a 2-min contact time. Several over-the-counter mouthwash/gargle products including Listerine and Listerine-like products were highly effective at inactivating infectious virus with greater than 99.9% even with a 30-s contact time. In the current manuscript we have demonstrated that several commonly available healthcare products have significant virucidal properties with respect to HCoV.

Experimental investigation on dye wastewater treatment with reverse electrodialysis reactor powered by salinity gradient energy

A novel advanced oxidation process technology for organic wastewater treatment was proposed in this paper. The working principle is that a low-grade heat (LGH) is first converted into a salinity gradient energy (SGE), and then the SGE is converted into the degradation energy of organic pollutions by a reverse electrodialysis (RED) reactor. To verify the feasibility of converting a SGE into a degradation energy by a RED reactor, an experimental investigation of dye wastewater treatment with a RED reactor powered by SGE had been done. The results showed that the output current of RED reactor, operating parameters of electrode rinse solution (ERS) and degradation circulation modes have effects on the decolorization of acid orange 7 (AO7) dye wastewater. Under the present experimental conditions, after 20 min treatment, the decolorization efficiencies of AO7 dye wastewater for the independent degradation circulation mode reached 99.93% and 96.52% in the anodic and cathodic loops respectively, while that for the synergetic degradation circulation mode reached 82.85%.

Inactivation of Escherichia coli K12 by pulsed UV light on goat meat and beef: microbial responses and modelling

SummaryThe objective of this study was to investigate the efficacy of pulsed UV light (PUVL) in inactivating Escherichia coli K12 on goat meat and beef surfaces. Inactivation studies were conducted for 5 to 60 s at three distances from the light source (4.47, 8.28 and 12.09 cm) in the PUVL chamber. Predictive models using regression and artificial neural networks (ANN) were developed to quantify log reductions. Pulsed UV light was more effective on beef than goat meat. Maximum log reductions of 1.66 and 1.74 CFU mL−1 rinse solution were achieved on goat meat and beef, respectively, at 4.47 cm distance for 60 s. Escherichia coli K12 reduction increased significantly with increasing treatment time and closer distance from the light source. In general, both ANN and regression models effectively described inactivation of E. coli K12. Predictive models describing PUVL inactivation kinetics of E. coli K12 can be used for process optimisation in meat industry.

Brief topical and intraluminal use of Carolina rinse solution does not attenuate experimental ischemia and reperfusion injury in rabbit jejunum

ABSTRACT Fifteen New Zealand adult rabbits were randomly allocated into three groups: Sham-operated (group A), Ischemia and Reperfusion (group B) and Carolina Rinse Solution (CRS) (group C). Groups B and C were subjected to one hour of ischemia and two hours of reperfusion. In group C, ten minutes before reperfusion, the bowel lumen was filled with CRS, and the segment immersed in CRS. Necrosis and loss of integrity of the villi were visible in groups B and C. Edema of the submucosa and circular muscle was observed in all groups. Hemorrhage was observed in different layers for groups B and C, but group C showed more severe hemorrhage in different layers during reperfusion. All groups showed polymorphonuclear leukocyte infiltration on the base of the mucosa, submucosa, and longitudinal muscle, in addition to polymorphonuclear leukocytes margination in the mucosal and submucosal vessels. Necrosis of enterocytes, muscles, crypts of Lieberkühn and myenteric plexus was observed in groups B and C during reperfusion. Topical and intraluminal Carolina Rinse Solution did not attenuate the effects of ischemia and reperfusion in the small intestine of rabbits.

Randomized controlled and double‐blinded study of Caphosol versus saline oral rinses in pediatric patients with cancer

Oral mucositis (OM) is a significant side effect of cancer treatment. The purpose of this study was to compare topically administered Caphosol to saline rinses in the prevention of mucositis in pediatric cancer patients. A controlled, double-blinded, and randomized clinical crossover study recruited patients between 2 to 17.99years of age who were diagnosed with a malignancy and were receiving either high-dose methotrexate (≥1g/m2 ), anthracycline, or cisplatin chemotherapy (NCT0280733). All patients received two 7-day cycles of the mouth rinses; that is, one cycle of Caphosol and one cycle of saline in a randomized order. Oral changes and symptoms were evaluated using the World Health Organisation (WHO) toxicity scale and the Children's International Mucositis Evaluation Scale (ChIMES). The primary endpoint was the frequency and severity of OM and oral symptoms. A total of 56 patients were recruited to the study, of whom 45 were randomized with a median age of 6.5years (range 2.1-17.1years). No cases of severe OM were observed. Grade≥3 oral symptoms were present at least once in six (13%) patients during the Caphosol cycle and 13 (29%) patients during the saline cycle (P=.12). The peak of symptom scores was evident at around day 4-7 after administration of the chemotherapy with no marked differences between the rinse solutions. Multivariable regression analysis did not indicate a benefit of using Caphosol over the saline solution. No difference in prevention of oral mucositis was observed between the use of Caphosol or saline rinses.

Estimation and influence of blood loss under endoscope for percutaneous endoscopic lumbar discectomy (PELD): a clinical observational study combined with in vitro experiment

PurposeThe purpose of this study is to come up with new methods to quantitate the blood loss under endoscope and explore the influence of blood loss on percutaneous endoscopic lumbar discectomy (PELD).MethodsClinical research and in vitro experiment are combined. In the in vitro experiment, 2.0-ml blood was diluted in different ratio to simulate the rinse solution of PELD, the hematocrit method (HCT-M) and red blood cell count method (RBC-M) were came up to estimate blood loss and the new methods were calibrated with the direct measurement method (Direct-M). In clinical research, 74 patients with L5/S1 disk herniation were treated with PELD, and HCT-M and the empirical method (EMP-M) were used to estimate the blood loss under endoscope. According to blood loss, all patients were divided into group A (≤ 10 ml) and group B (> 10 ml). The blood loss, operation time, fluoroscopy frequency, visual analog scale (VAS), and Oswestry Disability Index (ODI) scores were compared between the two groups.ResultsIn the in vitro experiment, the hematocrit of the rinse solution was always stable over time. The estimated blood loss by HCT-M was stable and quite approximate to actual blood volume (2.0 ml) whatever the blood dilution ratio, while according to RBC-M, the estimated blood loss was close to the actual blood volume only when the dilution ratio was greater than 300 times. In clinical research, the blood loss estimated by HCT-M was higher than that by EMP-M in both groups (P < 0.05). There was a significant difference between group A and group B in blood loss (7.40 ± 1.61 vs 19.91 ± 10.94 ml), operation time (80.51 ± 34.70 vs 136.51 ± 41.88 min), and fluoroscopy frequency (6.92 ± 1.52 vs 11.11 ± 2.32 times) (P < 0.05). The VAS and ODI scores in group B were higher than that in group A 1 week after operation (P < 0.05); however, the scores were not different between the two groups at pre-operation (P > 0.05).ConclusionHCT-M is a reliable method to estimate endoscopic blood loss in PELD. The amount of endoscopic blood loss affects the operative procedure in operation time and fluoroscopy frequency, as well as clinical effects in VAS and ODI scores after operation in short term.

Comparison of In Vitro Inactivation of SARS CoV-2 with Hydrogen Peroxide and Povidone-Iodine Oral Antiseptic Rinses.

PurposeTo evaluate the in vitro inactivation of severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) with hydrogen peroxide (H2O2) and povidone‐iodine (PVP‐I) oral antiseptic rinses at clinically recommended concentrations and contact times.Materials and MethodsSARS‐CoV‐2, USA‐WA1/2020 strain virus stock was prepared prior to testing by growing in Vero 76 cells. The culture media for prepared virus stock was minimum essential medium (MEM) with 2% fetal bovine serum (FBS) and 50 µg/mL gentamicin. Test compounds consisting of PVP‐I oral rinse solutions and H2O2 aqueous solutions were mixed directly with the virus solution so that the final concentration was 50% of the test compound and 50% of the virus solution. Thus PVP‐I was tested at concentrations of 0.5%, 1.25%, and 1.5%, and H2O2 was tested at 3% and 1.5% concentrations to represent clinically recommended concentrations. Ethanol and water were evaluated in parallel as standard positive and negative controls. All samples were tested at contact periods of 15 seconds and 30 seconds. Surviving virus from each sample was then quantified by standard end‐point dilution assay and the log reduction value of each compound compared to the negative control was calculated.ResultsAfter the 15‐second and 30‐second contact times, PVP‐I oral antiseptic rinse at all 3 concentrations of 0.5%, 1.25%, and 1.5% completely inactivated SARS‐CoV‐2. The H2O2 solutions at concentrations of 1.5% and 3.0% showed minimal viricidal activity after 15 seconds and 30 seconds of contact time.ConclusionsSARS‐CoV‐2 virus was completely inactivated by PVP‐I oral antiseptic rinse in vitro, at the lowest concentration of 0.5 % and at the lowest contact time of 15 seconds. Hydrogen peroxide at the recommended oral rinse concentrations of 1.5% and 3.0% was minimally effective as a viricidal agent after contact times as long as 30 seconds. Therefore, preprocedural rinsing with diluted PVP‐I in the range of 0.5% to 1.5% may be preferred over hydrogen peroxide during the COVID‐19 pandemic.

The Effects of Caffeine Mouth Rinsing on Exercise Performance: A Systematic Review.

Caffeine ingestion can improve performance across a variety of exercise modalities but can also elicit negative side effects in some individuals. Thus, there is a growing interest in the use of caffeine mouth rinse solutions to improve sport and exercise performance while minimizing caffeine's potentially adverse effects. Mouth rinse protocols involve swilling a solution within the oral cavity for a short time (e.g.,5-10s) before expectorating it to avoid systemic absorption. This is believed to improve performance via activation of taste receptors and stimulation of the central nervous system. Although reviews of the literature indicate that carbohydrate mouth rinsing can improve exercise performance in some situations, there has been no attempt to systematically review the available literature on caffeine mouth rinsing and its effects on exercise performance. To fill this gap, a systematic literature search of three databases (PubMed, SPORTDiscus, and Web of Science) was conducted by two independent reviewers. The search resulted in 11 randomized crossover studies that were appraised and reviewed. Three studies found significant positive effects of caffeine mouth rinsing on exercise performance, whereas the remaining eight found no improvements or only suggestive benefits. The mixed results may be due to heterogeneity in the methods across studies, interindividual differences in bitter tasting, and differences in the concentrations of caffeine solutions. Future studies should evaluate how manipulating the concentration of caffeine solutions, habitual caffeine intake, and genetic modifiers of bitter taste influence the efficacy of caffeine mouth rinsing as an ergogenic strategy.

Combination of Slotted Quartz Tube Flame Atomic Absorption Spectrometry and Dispersive Liquid–Liquid Microextraction for the Trace Determination of Silver in Electroplating Rinse Bath

Although flame atomic absorption spectrometry (FAAS) is hindered by its low sensitivity for most elements, it remains a widely used analytical technique in most laboratories. This study was aimed at mitigating the low sensitivity of an FAAS system by using dispersive liquid-liquid microextraction (DLLME) to enrich silver from aqueous solution, and enhance absorbance signals with the help of a slotted quartz tube (SQT). Three major optimization steps were carried for parameters of complexation (silver-dithizone), DLLME method and SQT apparatus. The optimum parameters/variables obtained were applied to aqueous standard solutions, and the developed calibration plots were used to validate the different systems studied. The optimized method (DLLME-SQT-FAAS) recorded an enhancement factor of 98, which correlates to detection and quantification limits of 0.60 µg/L and 2.0 µg/L, respectively. The optimized method was applied to an electroplating rinse solution, and close to 100% recovery results were obtained for different spiked concentrations. These results establish that the developed method can be applied to complex samples for accurate quantification of silver.

Chronic rhinosinusitis disease control as a metric for guiding treatment.

The assessment of Chronic Rhinosinusitis, like any other disease, may involve multiple possible disease manifestations, including subjective patient-reported outcomes, objective disease (e.g. endoscopy or radiographic), and physician-driven (e.g. need for systemic medications). Disease control is often used as a global metric of disease burden and represents the extent to which disease manifestations are within an acceptable range. Achieving control is an important treatment goal.

Oral Candida Mannan Concentrations Correlate with Symptoms/Signs of Ill Health and the Immune Status.

A relationship has been proposed between increases in oral Candida concentrations and host immunity. Therefore, the present study was conducted to investigate the relationship between oral Candida mannan concentrations and symptoms/signs of ill health and the immune status and also to examine whether health/the immune status may be evaluated based on oral Candida mannan concentrations. The health conditions of 25 healthy individuals and 10 cancer patients receiving cytotoxic chemotherapy were assessed using a questionnaire and oral rinse solutions collected on consecutive days. Candida mannan concentrations in oral rinse solutions were measured using a commercial sandwich ELISA kit. The use of dentures was identified as a significant independent factor increasing Candida mannan concentrations. In a stratified analysis based on the use of dentures, significantly increased Candida mannan concentrations were detected in healthy volunteers with chills and in cancer patients with slight/moderate fever (37.5-38.4°C) (multivariate analysis, p < 0.01) who were non-denture users. These symptoms/signs may be associated with (pre-)infection, during which the immune system is activated and needs to function well. The present results suggest that oral Candida mannan concentrations are a predictive marker for health/the immune status.

Detection of four major potato viruses in Japan using a simple RNA preparation and one-step multiplex RT-PCR

A high-throughput alternative to ELISA to detect potato leafroll virus (PLRV), potato virus S (PVS), potato virus X (PVX), and potato virus Y (PVY), economically important viruses in Japan, has been needed for seed potato production. To develop an alternative using a multiplex reverse transcription polymerase chain reaction (mRT-PCR), we verified reported primers by two-step mRT-PCR and designed new primers for PVS and PVY based on the conserved region of genome sequences among three lineages of PVS or six strains of PVY. In addition, primers specific for potato and tobacco elongation factor 1 alpha were designed as an internal control for mRT-PCR. With these primers, one-step mRT-PCR detected all reference isolates of the four viruses. A published paper-based RNA preparation was modified for use in a single tube with an elution procedure to preserve RNA as evidence. As a rinse solution to wash away contaminants, 50% (v/v) isopropanol and 75% (v/v) ethanol resulted in a sensitivity for all viruses was tenfold higher than with the buffered detergent. In the mRT-PCR, the optimized paper-based RNA preparation gave tenfold higher sensitivity than the other two RNA preparation methods. Compared with ELISA, the new RNA preparation with the mRT-PCR was tenfold more sensitive for PVY and PLRV, 1,000-fold more for PVX, but the same for PVS. The new detection method simultaneously detected the four potato viruses from potato leaf by group test and is efficient and sensitive enough to detect the four potato viruses for seed potato certification, quarantine, breeding, and field surveys.

Probiotics as a prophylaxis to prevent oral candidiasis in patients with Sjogren's syndrome: a double-blinded, placebo-controlled, randomized trial.

Patients with Sjögren's syndrome are at a higher risk to develop oral candidiasis than the general population. As antifungals have many side-effects, new approaches are needed to address this problem. This randomized controlled study aimed to evaluate the short-term efficacy of probiotics in the reduction of oral candidal growth in patients with SS. Thirty-two Sjogren's syndrome patients were randomly allocated in two groups receiving either Probiotics or placebo capsules twice a day for 5weeks. The strains included in the probiotic capsule were Lactobacillus acidophilus, Lactobacillus bulgaricus, Streptococcus thermophilus and Bifidobacteriumbifidum. Oral rinse solution samples were collected and candidal levels were determined (CFU/mL) at baseline and after the 5-week experimental period. Pain, erythema and angular cheilitis were also assessed at baseline and after 2, 4 and 5-week. In the probiotic group, there was a statistically significant reduction of the candidal load from baseline to the 5th week respectively. However, the change in candidal load at the same time in the placebo group was not statistically significant. The tested probiotic product may represent an unconventional method to reduce candidal colonization, to prevent oral candidosis in patients with Sjogren's syndrome.Clinical trials registration ID NCT03840538 (https://clinicaltrials.gov/show/NCT03840538).

Thermogravimetric Analysis and Mass Spectrometry Allow for Determination of Chemisorbed Reaction Products on Metal Organic Frameworks.

Thermogravimetric analysis (TGA) is a technique which can probe chemisorption of substrates onto metal organic frameworks. A TGA method was developed to examine the catalytic oxidation of S-nitrosoglutathione (GSNO) by the MOF H3[(Cu4Cl)3(BTTri)8] (abbr. Cu-BTTri; H3BTTri = 1,3,5-tris(1H-1,2,3-triazol-5-yl)benzene), yielding glutathione disulfide (GSSG) and nitric oxide (NO). Thermal analysis of reduced glutathione (GSH), GSSG, GSNO, and Cu-BTTri revealed thermal resolution of all four analytes through different thermal onset temperatures and weight percent changes. Two reaction systems were probed: an aerobic column flow reaction and an anaerobic solution batch reaction with gas agitation. In both systems, Cu-BTTri was reacted with a 1 mM GSH, GSSG, or GSNO solution, copiously rinsed with distilled-deionized water (dd-H2O), dried (25 °C, < 1 Torr), and assessed by TGA. Additionally, stock, effluent or supernatant, and rinse solutions for each glutathione derivative within each reaction system were assessed by mass spectrometry (MS) to inform on chemical transformations promoted by Cu-BTTri as well as relative analyte concentrations. Both reaction systems exhibited chemisorption of glutathione derivatives to the MOF by TGA. Mass spectrometry analyses revealed that in both systems, GSH was oxidized to GSSG, which chemisorbed to the MOF whereas GSSG remained unchanged during chemisorption. For GSNO, chemisorption to the MOF without reaction was observed in the aerobic column setup, whereas conversion to GSSG and subsequent chemisorption was observed in the anaerobic batch setup. These findings suggest that within this reaction system, GSSG is the primary adsorbent of concern with regards to strong binding to Cu-BTTri. Development of similar thermal methods could allow for the probing of MOF reactivity for a wide range of systems, informing on important considerations such as reduced catalytic efficiency from poisoning, recyclability, and loading capacities of contaminants or toxins with MOFs.

Effect of glucose and sodium chloride mouth rinses on neuromuscular fatigue: a preliminary study

Carbohydrate (CHO) mouth rinse has been shown to improve endurance performance and maintain the central drive of contracting muscles. Salt (NaCl) mouth rinse solution, often used in dentistry to desensitise the oral cavity to pain, could also activate cortical areas of the brain. Hence, the objective of this preliminary study was to investigate whether CHO (glucose) and NaCl mouth rinses could attenuate the reduction in maximum voluntary contraction (MVC) and sustained MVC (sMVC) following an endurance exercise (30-minute cycling at 70% VO2max). Ten subjects (male, age: 22 ± 1 years, weight: 65.3 ± 12.4 kg, height: 164.5 ± 7.5 cm, VO2max: 48.3 ± 6.1 mL kg−1 min−1) completed three trials of 30-minute cycling exercise. In a randomised cross-over study, in each trial, the participants rinsed using either water, 6% glucose, or 6% NaCl solution for 5 s immediately prior to and every 10 min during the cycling exercise. The MVC and sMVC were measured pre and post cycling. Analysis of variance showed significant interaction and time effects for MVC, while for sMVC there was a significant interaction with time and group effects. Both MVC and sMVC were higher post cycling in the glucose and NaCl groups compared to the water group, which suggests that activation of glucose and NaCl oral receptors could better preserve post-exercise force production. This is the first study to show that NaCl mouth rinse can produce a comparable effect on glucose. Hence, mouth rinses may be able to activate other distinct pathways that could attenuate fatigue.

Carbohydrate mouth rinse has no effects on behavioral or neuroelectric indices of cognition

Rinsing the mouth with a carbohydrate solution has been suggested as a means to enhance aspects of both physical and cognitive performance. However, evidence in support of these assertions is relatively weak. The purpose of this study was to investigate the effects of a carbohydrate mouth rinse solution on motor speed, inhibition, and sustained attention as indexed by both behavioral and neuroelectric measures. Using a double-blind, placebo-controlled, within-subjects crossover design, 50 college-aged young adults performed a battery of cognitive tasks both before and after rinsing their mouth for 10 s with 20 mL of either a carbohydrate mouth rinse solution or a sensory-matched placebo control solution. A simple tapping task was used as a measure of motor speed, a modified Eriksen flanker task was used to index inhibition, and a rapid visual information processing task was used as a measure of sustained attention. Participants demonstrated longer reaction times in the Flanker task after rinsing their mouths with the carbohydrate mouth rinse, relative to pretest. No differences in reaction time were observed for the placebo control condition. P3 latency in the Flanker task as an index of attentional processing speed was shorter at posttest than at pretest in the placebo control – but not the carbohydrate mouth rinse – condition. These results suggest that despite claims of cognitive enhancement, carbohydrate mouth rinses do not appear to alter motor speed, inhibition, or sustained attention as compared to a placebo control in non-physically-fatigued college-aged adults.

An improved process for the collection and DNA analysis of fired cartridge cases

Improvements to the DNA analysis of fired cartridge cases have been made in recent years, yet successful analysis of this important evidence type remains difficult. In this study, we describe both a novel device for the collection and transport of fired cartridge cases and a new DNA recovery method that incorporates a rinse-and-swab technique. This technique combines two different types of swabs and a rinse solution with additives that reduce the degradative effects that copper has on DNA. The new recovery method yielded approximately threefold more DNA than the traditional double swab method and reduced the evidence of degradation. After validation, we estimated the real-world success rate of obtaining DNA profiles suitable for comparison with the rinse-and-swab method by testing over 100 cartridge cases collected from crime scenes. Approximately 67 % of the time (8 of 12), at least one DNA profile suitable for comparison was obtained from fired cartridge cases assumed to be associated with a single firearm using the collection device and the rinse-and-swab method when the fired cartridge cases were collected within 24 h.

A Comparative Evaluation of Phytic Acid as Final Rinse Solution with Other Chelating Agents for Elimination of Intraradicular Smear: A Scanning Electron Microscopy Study.

ABSTRACTAim:The aim of this study was to compare radicular smear layer removal ability of different solutions of phytic acid (PA) with other chelating agents when used in specific irrigant protocols.Materials and Methods:Seventy four maxillary central incisors were collected, standardized, and canals were prepared. A total of 5% sodium hypochlorite was used as the initial rinse solution (8mL). Samples were divided into control (Group I—normal saline and II—7% ethylenediaminetetraacetic acid) and experimental groups (Group III, IV, V, VI, VII, and VIII) based on the type of final rinse solution used, that is, 5% PA, 10% PA, 17% PA, 5% citric acid (CA), 10% CA, and 17% CA (5mL). Samples were coded, buccolingually divided into two halves, dehydrated, mounted, splutter coated, and examined under scanning electron microscope.Results:Group IV had the least smear and debris in coronal, middle, and apical thirds with mean scores of 1.06 and 1.3, respectively. When compared with Group II, no statistically significant difference was found (P > 0.05). Overall, the Group III had the lowest erosion scores at apical, middle, and coronal one-third with a mean of 1.68. Group VII had the highest amount of erosion with loss of peritubular and intertubular dentin at all levels.Conclusion:The role of PA as final rinse solution for the removal of radicular smear is promising and comparable to other chelating agents.

Evaluation of Swab and Rinse Sampling Procedures and Recovery Rate Determination in Cleaning Validation Considering Various Surfaces, Amount and Nature of the Residues and Contaminants.

A cleaning validation for a family of compounds utilizing swab sampling and rinse solution procedures, and high performance liquid chromatography for separation and detection of the analytes was performed.Effective parameters on recovery including sampling method, swab characteristics, solvent, swabbing technique, and material substance of product contact surfaces within the manufacturing equipment for swab and rinse sampling method, quantitative cleaning verification method, and active pharmaceutical ingredient (API) level and nature have been studied.The limit of detection and the limit of quantitation for the HPLC method were determined to be 0.0198 µg/mL, and 0.0495 µg/mL of the analyte, respectively. The linearity on replicate injections of the standard prepared in the range of 0.78, 1.55, 3.1, and 6.2 µg/mL, and relative standard deviation (R.S.D.) found to be 1.2, 1.0, 0.9, and 0.6, respectively with correlation coefficient of R2 = 0.9999. Recovery coverage for each type of surface was acceptable, ranging from 63.88% for swab sampling of stainless steel to 97.85% for rinse sampling of PVC. The acceptance criteria for precision on replicate injections of the analyte prepared in three concentration levels covering the specified range of 50, 100, and 200% was successfully accomplished R.S.D. lower than 15% for recovery results.Thus, choosing the appropriate sampling method, swab type, and surface condition can affect and increase recovery rate determination efficiency.

Investigating Ammonium By-product Removal for Ureolytic Bio-cementation Using Meter-scale Experiments

Microbially Induced Calcite Precipitation (MICP), or bio-cementation, is a promising bio-mediated technology that can improve the engineering properties of soils through the precipitation of calcium carbonate. Despite significant advances in the technology, concerns regarding the fate of produced NH4+ by-products have remained largely unaddressed. In this study, five 3.7-meter long soil columns each containing one of three different soils were improved using ureolytic bio-cementation, and post-treatment NH4+ by-product removal was investigated during the application of 525 L of a high pH and high ionic strength rinse solution. During rinsing, reductions in aqueous NH4+ were observed in all columns from initial concentrations between ≈100 mM to 500 mM to final values between ≈0.3 mM and 20 mM with higher NH4+ concentrations observed at distances furthest from the injection well. In addition, soil Vs measurements completed during rinse injections suggested that no significant changes in cementation integrity occurred during NH4+ removal. After rinsing and a 12 hour stop flow period, all column solutions achieved cumulative NH4+ removals exceeding 97.9%. Soil samples collected following rinsing, however, contained significant sorbed NH4+ masses that appeared to have a near linear relationship with surrounding aqueous NH4+ concentrations. While these results suggest that NH4+ can be successfully removed from bio-cemented soils, acceptable limits for NH4+ aqueous concentrations and sorbed NH4+ masses will likely be governed by site-specific requirements and may require further investigation and refinement of the developed techniques.