Injection sequence

Figure 7 Addition of noise to the detector signal of a single pulse chromatographic run and a run using a PRBS injection sequence.

Chiral or achiral assay and purity determinations are done according to an external calibration calculation procedure, either with or without internal standardization. The calibration is performed against a 10% w/w (compared to the nominal concentration of the sample solution at 100% w/w) reference standard solution. The sample solution for the purity determination remains at the 100% w/w level, while that of the assay determination is diluted 10 times. The reason for the difference in concentration levels is similar to the purity method. A suggested sample injection sequence can be... 

Enantiomeric assay determinations are typically applied to characterize racemic mixtures using the normalized peak area (area%) calculation procedure. The selectivity solution is utilized to demonstrate the separation capability in the method and to allow peak identification. A suggested sample injection sequence can be... 

The sample solution for the limit test determination remains at the 100% w/w level. A suggested sample injection sequence can be... 

The injection sequence, which results in a highly sooting flame (Fig. 6.13), occurs out of phase with the air vortex formation. The first fuel injection misses the air vortex and stays unmixed while also partially suppressing the roll-up of this air vortex. The second-fuel injection enters the void between the air vortices and stays separated from the air. The rich mixture results in the formation of soot at this point as shown by the white spots. Temperature profiles also show the energy release rate to be lower in this case. 

The error terms might be correlated with each other or with an external parameter (i.e., time, injection sequence). It is always a good idea to plot the residuals vs. time and injection sequence to evaluate possible correlation effects. Detector drift, carry-over or other elfects can be easily detected with these plots. For a correct evaluation of the independence of the error, however, the calibration solutions should be injected in a randomized manner and correction for heteroskedasticity and/or curvilinearity should be applied on the calibration model. 

It has been demonstrated that, when many samples are to be analyzed in automatically injected sequences, the APCI mode is more stable than the ESI mode for quantitation [32]. However, the ESI mode is more sensitive for the detection ofthe pyrrolizidine- N-oxides. 

Presentation of injection sequences should be harmonized calibration, sample, sample, calibration, ... 

Data Acquisition and Control System. Computer-based system that controls all parameters of HPLC instrument (eluent composition (mixing of different solvents) temperature, injection sequence, etc.) and acquires data from the detector and monitors system performance (continuous monitoring of the mobile-phase composition, temperature, backpressure, etc.). 

Laboratory tests with Alipal CD-128 indicated that a steady-state reciprocal apparent viscosity of 0.2-0.4 cP (about equal to that of the oil) could be obtained and that surfactant retention by the reservoir rock would not be excessive (0.00056 lb surfac-tant/ft of rock permanent adsorption). Eventually, the following injection sequence was planned (1) 15 kg of NH4SCN tracer in 371 bbl of water, followed by a water spacer between the tracer and the subsequent surfactant solution (2) 2,764 bbl of 0.1% surfactant, intended to satisfy the adsorption requirements of the rock ... 

Assuming that the single Si-F ligand at the kink site is sufficiently polar to allow successive reaction of the two Si-Si backbonds with HF, then the overall reaction is consistent with pore formation in n- and p-type silicon where two charges are transferred per silicon atom. For the case of photoanodic dissolution of n-type silicon in NH4F [120-124] the characteristic photomultiplication effect at low light intensities is also consistent with the hole capture/electron injection sequence shown in Fig. 29 a. 

The injection scheme was optimized by simnlation using the modified UTCHEM 6.0. The final selected formula was 2% NaC03 + 1000 mg/L 1175A. The simulation results showed that the performance from different injection sequences was similar for the same mass of chemicals. Operation experience shows that polymer viscosity would be reduced by about 50% from the surface to the wellbore by mechanical shear loss, iron effect, and bacteria degradation. Therefore, in the performance prediction, the viscosity was assumed to be 50% of the measured viscosity in the laboratory. Economic analysis was also included in the optimization process to select the best injection scheme. 

Sample set or sequence method Controls and documents parameters of autosampler and sample/standard information Injection sequence vial, inject volume, injections, run time Functions inject samples, equilibrate, calibrate, quantitate Standard/sample info name, amount, sample weight, label claim, level... 

Fig. 9.7.6 Schematic of injection sequence on Synovec LC chip. (A) Chip in standby mode sample stream entering separation channel from above, mobile phase stream flowing from left side inlet channel, both streams exiting chip in side channel leading to the right. (B) Chip in injection mode external valve momentarily closes to stop exit...

Fig. 6 FI manifold with gas-diffusion separator nested in sample loop of the injection valve used for preconcentration of volatile species by time-bas sampling (sample loading sequence). AS, autosampler, T, heating thermostat (optional) CDS, gas-diffusion separator, V, injection valve Ri, reagent for generation of volatile species R2. acceptor reagent stream R3. derivatization reagent (optional) D, detector W, waste a, valve position in sample injection sequence. Crossed circles in valve represent blocked channels [20].

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