HPLC A Practical User’s Guide P2 potx

... equilibrated and standardized, we are ready to carry out an HPLC separation on a real sample. We might add an internal standard (if necessary, to correct for injection variations), dilute our sample ... internal stan- dard to both our sample and our known standard mixture, we can calculate peak heights or areas relative to that of the internal standard. Variations in the injection size of...

Ngày tải lên: 03/07/2014, 12:20

... solvent. 8 ADVANTAGES AND DISADVANTAGES OF HPLC 1 ADVANTAGES AND DISADVANTAGES OF HPLC 3 The first things we need to understand are how an HPLC system works, its best applications and advantages over ... remember that HPLC is both an analytical and a preparative tool. Often the preparative capabilities of the HPLC are over- looked. While normal analytical injections contain picogra...

Ngày tải lên: 23/01/2014, 04:20

... remember that HPLC is both an analytical and a preparative tool. Often the preparative capabilities of the HPLC are over- looked. While normal analytical injections contain picogram to nanogram quantities, ... tool.Twenty-five years in HPLC, first as a user, then in field sales and application support for HPLC manufacturers, and finally working as a teacher and consultant has shown m...

Ngày tải lên: 03/07/2014, 12:20

... residual plots – standard errors and t tests – covariance and correlation matrices of parameter estimates and equation errors  predicted values, residuals, parameter estimates, and variance-covariance ... heteroscedasticity  bivariate probit  bivariate Tobit  sample selection models ARIMA (Box-Jenkins) and ARIMAX (Box-Tiao) Modeling and Forecasting ✦ 31 ARIMA (Box-Jenkins) and ARIMAX (Box...

Ngày tải lên: 02/07/2014, 14:21

... SASECRSP, SASEFAME, and SASEHAVR interface engines enable SAS users to access and process time series data in CRSPAccess data files, FAME databases, and Haver Analytics Data Link Express (DLX) data bases, ... temporary data set that contains one observation for each value of each series. data temp; length _name_ $8 _label_ $40; keep _name_ _label_ date value; format date monyy.; input _name_ m...

Ngày tải lên: 02/07/2014, 14:21

... regressor variables, ˇ is a column vector of structural parameters, and  t is normally and independently distributed with a mean of 0 and a variance of  2 . Note that in this parameterization, ... linear hypothesis to be tested. If more than one equation is specified, the equations are separated by commas. Each test is written as a linear equation composed of constants and parameter...

Ngày tải lên: 02/07/2014, 14:21

... 192.426133 MAPE 21.0772644 HQC 190.536976 Durbin-Watson 1.3321 Regress R-Square 0.5717 Total R-Square 0.7717 Parameter Estimates Standard Approx Variable DF Estimate Error t Value Pr > |t| Variable Label Intercept ... behavior can be explained by the partial adjustment and adaptive expectation hypotheses. Short-term forecasting applications often use autoregressive models because these mod...

Ngày tải lên: 02/07/2014, 14:21

... usual. OUT= Data Set The output data set contains the following variables:  BY variables  a numeric variable _TYPE_  a character variable _NAME_  the column variables from the COMPUTAB data table Order ... Values Missing values for variables in programming statements are treated in the same way that missing values are treated in the DATA step; that is, missing values used in expressio...

Ngày tải lên: 02/07/2014, 14:21

... 175.820 Reading Data Files The DATASOURCE procedure is designed to read data from many different files and to place them in a SAS data set. For example, if you have a DRI Basic Economics data file you want ... Survey  Standard & Poor’s Compustat Services Financial Database Files:  COMPUSTAT Annual  COMPUSTAT 48 Quarter  COMPUSTAT Full Coverage Annual  COMPUSTAT Full Coverage 48 Qua...

Ngày tải lên: 02/07/2014, 15:20

... that fall alphabetically between DATA1 and DATA99, and between DATA151 and DATA350. Finally, the third statement assigns a length of 4 bytes to all the numeric variables defined between DATA1 and ... the BEANIPA Data Relation of Foreign Transactions to Balance of Payment Accounts Range from 1984 to 1989 Annual The CONTENTS Procedure Alphabetic List of Variables and Attributes # Variable Type...

Ngày tải lên: 02/07/2014, 15:20