Automated Method for the Determination of Direct Available P2O5 in Fertilizers

1973 ◽  
Vol 56 (5) ◽  
pp. 1078-1083
Author(s):  
Larry G Hambleton
Keyword(s):  
Primary Standard ◽  
Sampling Rate ◽  
Gravimetric Method ◽  
Ammonium Citrate ◽  
Photometric Method ◽  
Ferric Pyrophosphate ◽  
Color Development ◽  
Automated Method ◽  
Significant Difference ◽  
Coloring Matter

Abstract An automated photometric method for the analysis of direct available P2O5 in fertilizers has been developed. The method utilizes basic AutoAnalyzer equipment along with a heating bath to destroy ammonium citrate and coloring matter and also to hydrolyze non-orthophosphates. The 0.15 and 0.35 mg P2O5/ml ranges are expanded to read 10 and 90% T, respectively, with a sampling rate of 30 analyses/ hr. Experiments were conducted to show the effect of acid and ammonium citrate concentrations on color development. The normality of acid needed to completely hydrolyze the phosphorus in non-orthophosphate samples was also determined. Results for samples of urea-ammonium polyphosphate, sodium pyrophosphate, sodium metaphosphate, and ferric pyrophosphate analyzed by the automated method are reported and compared to results on the same samples analyzed by the official final action gravimetric quinolinium molybdophosphate method, 2.023–2.025; good agreement was shown between the methods. Six replicate determinations on 5 mixed fertilizer samples and a KH2PO4 primary standard by each method were in close agreement. The accuracy of the automated method was confirmed by analyzing 312 routine fertilizer samples by both the automated method and the gravimetric method; results did not show a significant difference when compared by Students’ l-test at the 5% level.

Automated Method for Determining Direct Available P2O5 in Fertilizers

1974 ◽  
Vol 57 (4) ◽  
pp. 785-790
Author(s):  
Larry L Wall ◽  
Charles W Gehrke
Keyword(s):  
Sampling Rate ◽  
Gravimetric Method ◽  
Ammonium Citrate ◽  
Slight Effect ◽  
Flow Rates ◽  
Automated Method ◽  
Accuracy And Precision ◽  
Analytical System ◽  
Hydrolysis Of ◽  
Heating Bath

Abstract In the automated method for the analysis of direct available and total P205 in fertilizers, a heating bath is used to destroy ammonium citrate and colored material and for hydrolysis of non-orthophosphates. The heating bath was maintained at 98°C and contained a 40' time delay coil, providing 15 min digestion. Improvements on the method for the automated digestion of citrate extracts of fertilizer included decreasing the reagent and sample flow rates by factors of 2 to 5. All of the citrate in those samples containing the highest levels of citrate was not destroyed; however, the slight effect of the remaining citrate could be eliminated by changing the concentration of the molybdovanadate reagent. No difficulty was encountered with the hydrolysis of non-orthophosphates. With this analytical system, steady state conditions were reached at a sampling rate of 40 samples/hr and with a 4 : 1 sample-to-wash ratio. Repeated analyses were made on 9 samples, and the accuracy and precision of results obtained by the automated method compared very well with data by the official AOAC gravimetric method.

Automation of the AOAC Photometric Phosphomolybdovanadate Method for Direct Available P2O5

1966 ◽  
Vol 49 (6) ◽  
pp. 1213-1218
Author(s):  
Charles W Gehrke ◽  
James H Baumgartner ◽  
James P Ussary
Keyword(s):  
Sampling Rate ◽  
Gravimetric Method ◽  
Photometric Method ◽  
Available Phosphorus ◽  
Automatic Method ◽  
Average Recovery ◽  
Automated Method ◽  
Relative Standard ◽  
Standard Deviations

Abstract An automatic photometric method utilizing the Technicon AutoAnalyzer has been developed to determine phosphorus in all forms of fertilizer phosphorus in the range of 2.0–4.5 mg P2O5/100 ml at a sampling rate of 40 analyses/hr. Multiple analyses of KH2PO4, 9 Magruder check samples, and numerous commercial fertilizers were made and compared with results obtained by the official quinolinium phosphomolybdate method, 2.025(b). Average range for five independent determinations was 0.22% P2O5 for the automated method and 0.26% P2O5 for the gravimetric method; average relative standard deviations were 0.44 and 0.60%, respectively. The average recovery of P2O5 from KH2PO4 was 99.8% with the photometric method and 100.3% with the quinolinium method. Results on 69 commercial fertilizers containing 5–54% P2O5 by the automatic method were only 0.02%% lower than those by the gravimetric quinolinium method. Results show that the automated phosphomolybdovanadate method for direct available phosphorus in fertilizers is accurate, precise, and less time consuming for routine control and industrial laboratories.

Missouri Automated Method for Total Nitrogen in All Fertilizers

1971 ◽  
Vol 54 (3) ◽  
pp. 651-657 ◽  
Author(s):  
Charles W Gehrke ◽  
Larry L Wall ◽  
John S Killingley ◽  
Kazuyoshi Inada
Keyword(s):  
Sampling Rate ◽  
Automated System ◽  
Commercial Fertilizer ◽  
Sodium Tartrate ◽  
Color Development ◽  
Colorimetric System ◽  
Automated Method ◽  
Solid Liquid ◽  
Interfering Ions ◽  
Effective Analysis

Abstract An automated spectrophotometric method, utilizing Technicon AutoAnalyzer modules, has been developed for the analysis of nitrogen in fertilizers. The continuous digestor, which was found to effectively digest organic materials in solution after the reduction step, is coupled with an automated colorimetric system. This colorimetric system employs the ammonia-phenate-hypochlorite reaction. The fertilizer samples are reduced manually via the comprehensive nitrogen method (CNM). The sampling rate chosen is 30 cups/hr (6 reference standards included) which yields an effective analysis rate of 24 samples/hr. The impinger mixer at the exit end of the digestor helix is replaced with a jacketed double-mixing coil and an AO glass fitting for a more stable baseline and improved precision. Manganous ions at a concentration of 5.0 ppm introduced into the color development manifold as a catalyst give a significant increase in sensitivity. When commercial fertilizer samples were analyzed with the automated system, consistently low results were obtained for some samples as compared to results obtained by the AOAC CNM. However, 0.01M potassium sodium tartrate in the color development manifold provides sufficient complexing potential to eliminate the effect of interfering ions. One hundred commercial fertilizer samples including solid, liquid, and suspension fertilizers were analyzed by the Missouri automated nitrogen method. The results agreed well with the results obtained by multiple independent analyses by the AOAC CNM. Details of the automated system, sample preparation, reagent concentrations and preparation, and experimental data are given.

scholarly journals Missouri Automated Nitrogen Method (MANM) for Fertilizers

1972 ◽  
Vol 55 (3) ◽  
pp. 467-480
Author(s):  
Charles W Gehrke ◽  
John S Killingley ◽  
Larry L Wall
Keyword(s):  
Standard Deviation ◽  
Total Nitrogen ◽  
Primary Standard ◽  
Relative Difference ◽  
Automated System ◽  
Urea Nitrogen ◽  
Average Value ◽  
Color Development ◽  
Automated Method ◽  
Relative Standard

Abstract An automated spectrophotometric method, utilizing Technicon AutoAnalyzer modules, has been developed to determine total nitrogen in fertilizers containing only ammoniacal, nitrate , and urea nitrogen. This colorimetric system employs the Berthelot ammoniaphenate- hypochlorite reaction. A homogeneous chromous/titanous reduction system for the automatic reduction of nitrates was interfaced with the digestion unit and color development manifold, resulting in a total nitrogen system for fertilizers with an effective analysis r a t e of 20-25 samples/hr. A new sample retrieval system removes digested samples from the helix. The totally automated system was optimized to obtain t h e highest sensitivity for nitrogen. Data were compared for 458 samples analyzed by the automated method and the comprehensive nitrogen method (CNM), 2.053–2.054. The average difference between the 2 methods (MANM – CNM) was +0.04% nitrogen. The average relative difference was 1.12%. The average value for 140 samples of KNO3 primary standard analyzed by the MANM was 13.84% nitrogen (theoretical content 13.85%). The results of these standards ranged from 13.58 to 14.14% nitrogen and the standard deviation was 0.11%. The relative standard deviation was 0.80%. Of fertilizer samples received for analysis, less than 1% contained insoluble organic nitrogenous material which was unsuitable for analysis by the MANM. These few samples were not included in the statistical evaluation. The MANM is rapid, accurate, and precise and is a convenient and dependable automated method for the determination of total nitrogen in fertilizers containing only ammoniacal, nitrate , and urea nitrogen.

scholarly journals Results of the infrasonic array on the Valaam Island primary data processing

2020 ◽  
Vol 2 (1) ◽  
pp. 85-91
Author(s):  
Vladimir Karpinsky ◽  
Vladimir Asming
Keyword(s):  
Data Processing ◽  
Seismic Station ◽  
Sampling Rate ◽  
Low Frequency ◽  
Primary Data ◽  
Joint Analysis ◽  
Main Task ◽  
Significant Difference ◽  
Infrasound Signal ◽  
Short Time

The infrasound array VALS developed in Kola Branch GS RAS has been installed in June 2016 on the Valaam Island in addition to the continuously operating seismic station VALR. The array consists of 3 spaced low-frequency microphones. The data with a sampling rate of 100 Hz is stored continuously at the acquisition computer; the timing is carried out using GPS. In addition to the acquisition system, an infrasound signal detector is installed on the computer. It works in near real-time mode and enables us to find signals and compute their back azimuths. At the end of 2018, a new version of the detector was developed at the Kola Branch GS RAS. The detector began to work much faster, which enabled us to carry out data processing for 2.5 years in two frequency ranges in a short time. The main task of the array is acoustic monitoring, the detection of infrasound events, the determination of their parameters, and the selection of events of natural origin. The data are also used (in combination with the VALR seismic station data) to locate near seismic events, especially weak ones. The analysis of the obtained data revealed the prevailing directions to the signal sources. The change of directions to sources in time was investigated, seasonal features were revealed. Acoustic events were detected in the frequency bands 1–5 Hz and 10–20 Hz, and a significant difference was found in the azimuthal distribution of events for these ranges. A joint analysis of acoustic and seismic data showed that the part of events with both acoustic and seismic components is low – it is almost completely exhausted by career explosions. It was also noted that in addition to explosions in nearby quarries (Kuznechnoye, Pitkäranta) located at a distance of 50–60 km, according to acoustic data, events corresponding to explosions at quarries located at a distance of 100 km or more were repeatedly identified.

scholarly journals Multicenter clinical validation of an on-line monitor of dialysis adequacy.

1996 ◽  
Vol 7 (3) ◽  
pp. 464-471
Author(s):  
T A Depner ◽  
P R Keshaviah ◽  
J P Ebben ◽  
P F Emerson ◽  
A J Collins ◽  
...  
Keyword(s):  
Solute Concentration ◽  
Dialysis Dose ◽  
Dialysis Adequacy ◽  
Automated Method ◽  
Baxter Healthcare ◽  
Significant Difference ◽  
Urea Kinetics ◽  
Nitrogen Concentrations ◽  
On Line ◽  
Paired Analysis

Quantitation of hemodialysis by measuring changes in blood solute concentration requires careful timing when taking the postdialysis blood sample to avoid errors from postdialysis rebound and from recirculation of blood through the access device. It also requires complex mathematical interpretation to account for solute disequilibrium in the patient. To circumvent these problems, hemodialysis can be quantified and its adequacy assessed by direct measurement of the urea removed in the dialysate. Because total dialysate collection is impractical, an automated method was developed for measuring dialysate urea-nitrogen concentrations at frequent intervals during treatment. A multicenter clinical trial of the dialysate monitoring device, the Biostat 1000 (Baxter Healthcare Corporation, McGaw Park, IL) was conducted to validate the measurements of urea removed, the delivered dialysis dose (Kt/V), and net protein catabolism (PCR). The results were compared with a total dialysate collection in each patient. During 29 dialyses in 29 patients from three centers, the paired analysis of urea removed, as estimated by the dialysate monitor compared with the total dialysate collection, showed no significant difference (14.7 +/- 4.7 g versus 14.8 +/- 5.1 g). Similarly, measurements of Kt/V and PCR showed no significant difference (1.30 +/- 0.18 versus 1.28 +/- 0.19, respectively, for Kt/V and 42.3 +/- 15.7 g/day versus 52.2 +/- 17.4 g/day for PCR). When blood-side measurements during the same dialyses were analyzed with a single-compartment, variable-volume model of urea kinetics, Kt/V was consistently overestimated (1.49 +/- 0.29/dialysis, P < 0.001), most likely because of failure to consider urea disequilibrium. Because urea disequilibrium is difficult to quantitate during each treatment, dialysate measurements have obvious advantages. The dialysate monitor eliminated errors from dialysate bacterial contamination, simplified dialysate measurements, and proved to be a reliable method for quantifying and assuring dialysis adequacy.

scholarly journals Comparison between Steiner cephalometric and modified Andrews photometric method for assessing antero-posterior position of the maxillary central incisors.

2019 ◽  
Vol 147 (11-12) ◽  
pp. 670-675
Author(s):  
Predrag Vucinic ◽  
Djordje Petrovic ◽  
Stojan Ivic ◽  
Sanja Vujkov
Keyword(s):  
Vertical Line ◽  
Photometric Method ◽  
Facial Features ◽  
Tooth Position ◽  
Facial Esthetics ◽  
Lateral Cephalograms ◽  
Significant Difference ◽  
Low Levels ◽  
Relationship Of ◽  
Posterior Position

Introduction/Objective. Maxillary incisors, when exposed during smile, are one of the most important facial features. In an attempt to overcome limitations of standard cephalometric methods, Andrews described an approach to determine ideal anteroposterior (AP) position of maxillary central incisors in smiling profile in relation to the forehead. We compared traditional Steiner cephalometric method, using surrounding skeletal landmarks, to the method proposed by Andrews, with the aim of determining whether distant but very noticeable craniofacial structures can affect our impression of tooth position. Methods. The study comprised 90 randomly selected lateral cephalograms, divided into three groups according to maxillary central incisors AP position according to Steiner cephalometric norms. The AP relationship of the maxillary central incisors was measured as a perpendicular distance from facial axis point to the nasion A line and to the vertical line through forehead facial axis point respectively. Student?s t-test and Pearson?s correlation were used to compare tested variables. Results. There was statistically significant difference between two methods (p = 0.01108). According to the Steiner method 46.67% subjects had retrusive incisors and 53.33% subjects had protrusion. Andrews?s method showed different results; 35.56% subjects had retrusion, while 64.4% had protrusion. Conclusion. The method proposed by Andrews showed consistently more protrusion than the traditional cephalometric method according to Steiner. Slightly retruded position of maxillary central incisors according to Steiner analysis does not always imply poor facial esthetics, if they have favorable position to the forehead. Low levels of correlation indicate that we should never rely on just one set of parameters.

A fully automated method for late ventricular diastole frame selection in post-dive echocardiography without ECG gating

2021 ◽  
pp. 73-80
Author(s):  
Eric Markley ◽  
◽  
David Q. Le ◽  
Peter Germonpré ◽  
Costantino Balestra ◽  
...  
Keyword(s):  
Field Experiments ◽  
High Reliability ◽  
Rater Bias ◽  
Algorithm Performance ◽  
Frame Selection ◽  
Automated Method ◽  
Significant Difference ◽  
Computer Automation ◽  
Decompression Stress ◽  
Selection Of

Venous gas emboli (VGE) are often quantified as a marker of decompression stress on echocardiograms. Bubble-counting has been proposed as an easy to learn method, but remains time-consuming, rendering large dataset analysis impractical. Computer automation of VGE counting following this method has therefore been suggested as a means to eliminate rater bias and save time. A necessary step for this automation relies on the selection of a frame during late ventricular diastole (LVD) for each cardiac cycle of the recording. Since electrocardiograms (ECG) are not always recorded in field experiments, here we propose a fully automated method for LVD frame selection based on regional intensity minimization. The algorithm is tested on 20 previously acquired echocardiography recordings (from the original bubble-counting publication), half of which were acquired at rest (Rest) and the other half after leg flexions (Flex). From the 7,140 frames analyzed, sensitivity was found to be 0.913 [95% CI: 0.875-0.940] and specificity 0.997 [95% CI: 0.996-0.998]. The method’s performance is also compared to that of random chance selection and found to perform significantly better (p<0.0001). No trend in algorithm performance was found with respect to VGE counts, and no significant difference was found between Flex and Rest (p>0.05). In conclusion, full automation of LVD frame selection for the purpose of bubble counting in post-dive echocardiography has been established with excellent accuracy, although we caution that high quality acquisitions remain paramount in retaining high reliability.

Collaborative Study of Turbidimetric Microbiological Assay of Monensin in Chicken Rations

1977 ◽  
Vol 60 (1) ◽  
pp. 179-182
Author(s):  
H Latham Breunig ◽  
Robert E Scroggs ◽  
Lealon V Tonkinson ◽  
Henry Bikin
Keyword(s):  
Experimental Design ◽  
Collaborative Study ◽  
Microbiological Assay ◽  
Assay Method ◽  
Turbidimetric Method ◽  
Automated Method ◽  
Relative Standard ◽  
Significant Difference ◽  
Feed Form ◽  
Automated Methods

Abstract A turbidimetric microbiological assay method for monensin in chicken rations was submitted in a modified form to 8 collaborating laboratories along with randomized and coded samples. Three laboratories used the manual method and 5 used the automated method. Other factors in the experimental design were ration types (broiler starter, broiler finisher, and pullet grower), feed form (meal vs. pellets), and potency level (90 and 110 g/ton) for one ration. Average recoveries for the ration types over all laboratories and feed forms were 87.7—93.13% of label, while mean recoveries in 2 feed forms were 91.7% for meal and 87.6% for pellets. Average recoveries in the 8 laboratories ranged from 84.6 to 106.64% of label for 90 g/ton rations and 87.1 to 106.6% for 110 g/ton rations. There was no significant difference between the manual and the automated methods. The collaborators’ assays were uniform with respect to within-laboratory variation. Relative standard deviations ranged from 4.51 to 10.76% with a median of 6.04%. Agreement with the plate assay is quite good. The turbidimetric method for monensin has been adopted as official first action.

Automatic Flame Photometric Determination of Potassium in Fertilizers. A. Elimination of Anion Exchange Cleanup. B. Using Direct Available P2O5 Extract

1965 ◽  
Vol 48 (6) ◽  
pp. 1095-1100
Author(s):  
James P Ussary ◽  
Charles W Gehrke
Keyword(s):  
Anion Exchange ◽  
Primary Standard ◽  
Photometric Determination ◽  
Photometric Method ◽  
Potassium Salts ◽  
Commercial Fertilizer ◽  
Aoac Official ◽  
Primary Standards ◽  
Standard Grade

Abstract Three primary standard grade potassium salts, eight Magruder check samples, and 18 commercial fertilizer samples were analyzed by three methods. Primary standards gave an average recovery of 100.0% and an average range of 0.21% K20. Magruder check samples averaged 0.09% K20 higher by the modified flame photometric method than the grand averages of the STPB results on the respective Magruder reports. The modified flame photometric method averaged 0.02% K20 lower than the official flame photometric method and 0.11% K20 higher than the official STPB method on 18 commercial fertilizer samples. The automatic flame photometric method, without anion exchange cleanup, is rapid enough for routine analysis and is as accurate and precise as the AOAC official methods. The method was also applied to the direct available P205 extract. Results on three primary grade potassium salts, seven Magruder check samples, and 13 commercial fertilizer samples were as accurate and precise as the official STPB method.

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