diff --git a/src/classes/PFitter.cpp b/src/classes/PFitter.cpp
index a25e1d69c..2d3394334 100644
--- a/src/classes/PFitter.cpp
+++ b/src/classes/PFitter.cpp
@@ -64,10 +64,9 @@
 #include <TFile.h>
 #include <TDatime.h>
 #include <TString.h>
-#include <TObjArray.h>
-#include <TObjString.h>
 
 #include "PFitter.h"
+#include "PStringUtils.h"
 
 
 //+++ PSectorChisq class +++++++++++++++++++++++++++++++++++++++++++++++++++
@@ -397,8 +396,6 @@ void PFitter::GetPhaseParams()
   // default functions:
   // user functions cannot be checked!
   PMsrLines *theo = fRunInfo->GetMsrTheory();
-  TObjArray *tok = nullptr;
-  TObjString *ostr = nullptr;
   TString str;
   int pos = -1;
   for (unsigned int i=0; i<theo->size(); i++) {
@@ -423,18 +420,10 @@ void PFitter::GetPhaseParams()
       continue;
 
     // extract phase token
-    tok = line.Tokenize(" \t");
-    if (tok == nullptr) {
-      std::cerr << "PFitter::GetPhaseParams(): **ERROR** couldn't tokenize theory line string." << std::endl;
-      return;
+    std::vector<std::string> tok = PStringUtils::Split(line.Data(), " \t");
+    if (static_cast<int>(tok.size()) > pos) {
+      str = tok[pos].c_str();
     }
-    if (tok->GetEntries() > pos) {
-      ostr = dynamic_cast<TObjString*>(tok->At(pos));
-      str = ostr->GetString();
-    }
-    // clean up
-    delete tok;
-    tok = nullptr;
 
     // decode phase token. It can be funX, mapX, or a number
     if (str.Contains("fun")) { // function
@@ -491,22 +480,15 @@ PIntVector PFitter::GetParFromFun(const TString funStr)
   PIntVector parVec;
 
   PMsrLines *funList = fRunInfo->GetMsrFunctions();
-  TObjArray *tok = nullptr;
-  TObjString *ostr = nullptr;
   TString str;
 
   for (int i=0; i<funList->size(); i++) {
     if (funList->at(i).fLine.Contains(funStr)) {
       // tokenize function string
-      tok = funList->at(i).fLine.Tokenize(" =+-*/");
-      if (tok == nullptr) {
-        std::cerr << "PFitter::GetParFromFun(): **ERROR** couldn't tokenize function string." << std::endl;
-        return parVec;
-      }
+      std::vector<std::string> tok = PStringUtils::Split(funList->at(i).fLine.Data(), " =+-*/");
 
-      for (int j=1; j<tok->GetEntries(); j++) {
-        ostr = dynamic_cast<TObjString*>(tok->At(j));
-        str = ostr->GetString();
+      for (int j=1; j<static_cast<int>(tok.size()); j++) {
+        str = tok[j].c_str();
         // parse tok for parX
         if (str.Contains("par")) {
           // find start idx of par in token
@@ -533,10 +515,6 @@ PIntVector PFitter::GetParFromFun(const TString funStr)
           }
         }
       }
-
-      // clean up
-      delete tok;
-      tok = nullptr;
     }
   }
 
@@ -996,16 +974,14 @@ Bool_t PFitter::CheckCommands()
       cmd.second = cmdLineNo;
       fCmdList.push_back(cmd);
       // filter out possible parameters for scan
-      TObjArray *tokens = nullptr;
-      TObjString *ostr;
+      std::vector<std::string> tokens;
       TString str;
       UInt_t ival;
 
-      tokens = line.Tokenize(", \t");
+      tokens = PStringUtils::Split(line.Data(), ", \t");
 
-      for (Int_t i=0; i<tokens->GetEntries(); i++) {
-        ostr = dynamic_cast<TObjString*>(tokens->At(i));
-        str = ostr->GetString();
+      for (Int_t i=0; i<static_cast<int>(tokens.size()); i++) {
+        str = tokens[i].c_str();
 
         if ((i==1) || (i==2)) { // parX / parY
           // check that token is a UInt_t
@@ -1016,10 +992,6 @@ Bool_t PFitter::CheckCommands()
             std::cerr  << std::endl << ">> command syntax for CONTOURS is: CONTOURS parameter-X parameter-Y [# of points]";
             std::cerr  << std::endl;
             fIsValid = false;
-            if (tokens) {
-              delete tokens;
-              tokens = nullptr;
-            }
             break;
           }
           ival = str.Atoi();
@@ -1031,10 +1003,6 @@ Bool_t PFitter::CheckCommands()
             std::cerr  << std::endl << ">> command syntax for CONTOURS is: CONTOURS parameter-X parameter-Y [# of points]";
             std::cerr  << std::endl;
             fIsValid = false;
-            if (tokens) {
-              delete tokens;
-              tokens = nullptr;
-            }
             break;
           }
           // keep parameter
@@ -1051,10 +1019,6 @@ Bool_t PFitter::CheckCommands()
             std::cerr  << std::endl << ">> command syntax for CONTOURS is: CONTOURS parameter-X parameter-Y [# of points]";
             std::cerr  << std::endl;
             fIsValid = false;
-            if (tokens) {
-              delete tokens;
-              tokens = nullptr;
-            }
             break;
           }
           ival = str.Atoi();
@@ -1065,20 +1029,12 @@ Bool_t PFitter::CheckCommands()
             std::cerr  << std::endl << ">> command syntax for CONTOURS is: CONTOURS parameter-X parameter-Y [# of points]";
             std::cerr  << std::endl;
             fIsValid = false;
-            if (tokens) {
-              delete tokens;
-              tokens = nullptr;
-            }
             break;
           }
           fScanNoPoints = ival;
         }
       }
 
-      if (tokens) {
-        delete tokens;
-        tokens = nullptr;
-      }
     } else if (line.Contains("EIGEN", TString::kIgnoreCase)) {
       cmd.first  = PMN_EIGEN;
       cmd.second = cmdLineNo;
@@ -1090,15 +1046,13 @@ Bool_t PFitter::CheckCommands()
       // (iii) FIT_RANGE start1 end1 start2 end2 ... startN endN
       // (iv)  FIT_RANGE fgb+n0 lgb-n1
       // (v)   FIT_RANGE fgb+n00 lgb-n01 fgb+n10 lgb-n11 ... fgb+nN0 lgb-nN1
-      TObjArray *tokens = nullptr;
-      TObjString *ostr;
+      std::vector<std::string> tokens;
       TString str;
 
-      tokens = line.Tokenize(", \t");
+      tokens = PStringUtils::Split(line.Data(), ", \t");
 
-      if (tokens->GetEntries() == 2) { // should only be RESET
-        ostr = dynamic_cast<TObjString*>(tokens->At(1));
-        str = ostr->GetString();
+      if (static_cast<int>(tokens.size()) == 2) { // should only be RESET
+        str = tokens[1].c_str();
         if (str.Contains("RESET", TString::kIgnoreCase)) {
           cmd.first = PMN_FIT_RANGE;
           cmd.second = cmdLineNo;
@@ -1110,32 +1064,23 @@ Bool_t PFitter::CheckCommands()
           std::cerr  << std::endl << ">>         with N the number of runs in the msr-file." << std::endl;
           std::cerr  << std::endl << ">>         Found " << str.Data() << ", instead of RESET" << std::endl;
           fIsValid = false;
-          if (tokens) {
-            delete tokens;
-            tokens = nullptr;
-          }
           break;
         }
-      } else if ((tokens->GetEntries() > 1) && (static_cast<UInt_t>(tokens->GetEntries()) % 2) == 1) {
-        if ((tokens->GetEntries() > 3) && ((static_cast<UInt_t>(tokens->GetEntries())-1)) != 2*fRunInfo->GetMsrRunList()->size()) {
+      } else if ((static_cast<int>(tokens.size()) > 1) && (static_cast<UInt_t>(static_cast<int>(tokens.size())) % 2) == 1) {
+        if ((static_cast<int>(tokens.size()) > 3) && ((static_cast<UInt_t>(static_cast<int>(tokens.size()))-1)) != 2*fRunInfo->GetMsrRunList()->size()) {
           std::cerr  << std::endl << ">> PFitter::CheckCommands: **ERROR** in line " << it->fLineNo;
           std::cerr  << std::endl << ">> " << line.Data();
           std::cerr  << std::endl << ">> Syntax: FIT_RANGE RESET | FIT_RANGE <start> <end> | FIT_RANGE <s1> <e1> <s2> <e2> .. <sN> <eN> |";
           std::cerr  << std::endl << ">>         FIT_RANGE fgb+<n0> lgb-<n1> | FIT_RANGE fgb+<n00> lgb-<n01> fgb+<n10> lgb-<n11> ... fgb+<nN0> lgb-<nN1>,";
           std::cerr  << std::endl << ">>         with N the number of runs in the msr-file.";
-          std::cerr  << std::endl << ">>         Found N=" << (tokens->GetEntries()-1)/2 << ", # runs in msr-file=" << fRunInfo->GetMsrRunList()->size() << std::endl;
+          std::cerr  << std::endl << ">>         Found N=" << (static_cast<int>(tokens.size())-1)/2 << ", # runs in msr-file=" << fRunInfo->GetMsrRunList()->size() << std::endl;
           fIsValid = false;
-          if (tokens) {
-            delete tokens;
-            tokens = nullptr;
-          }
           break;
         } else {
           // check that all range entries are numbers or fgb+n0 / lgb-n1
           Bool_t ok = true;
-          for (Int_t n=1; n<tokens->GetEntries(); n++) {
-            ostr = dynamic_cast<TObjString*>(tokens->At(n));
-            str = ostr->GetString();
+          for (Int_t n=1; n<static_cast<int>(tokens.size()); n++) {
+            str = tokens[n].c_str();
             if (!str.IsFloat()) {
               if ((n%2 == 1) && (!str.Contains("fgb", TString::kIgnoreCase)))
                 ok = false;
@@ -1158,10 +1103,6 @@ Bool_t PFitter::CheckCommands()
             std::cerr  << std::endl << ">>         with N the number of runs in the msr-file.";
             std::cerr  << std::endl << ">>         Found token '" << str.Data() << "', which is not a floating point number." << std::endl;
             fIsValid = false;
-            if (tokens) {
-              delete tokens;
-              tokens = nullptr;
-            }
             break;
           }
         }
@@ -1172,29 +1113,19 @@ Bool_t PFitter::CheckCommands()
         std::cerr  << std::endl << ">>         FIT_RANGE fgb+<n0> lgb-<n1> | FIT_RANGE fgb+<n00> lgb-<n01> fgb+<n10> lgb-<n11> ... fgb+<nN0> lgb-<nN1>,";
         std::cerr  << std::endl << ">>         with N the number of runs in the msr-file.";
         fIsValid = false;
-        if (tokens) {
-          delete tokens;
-          tokens = nullptr;
-        }
         break;
       }
 
-      if (tokens) {
-        delete tokens;
-        tokens = nullptr;
-      }
     } else if (line.Contains("FIX", TString::kIgnoreCase)) {
       // check if the given set of parameters (number or names) is present
-      TObjArray *tokens = nullptr;
-      TObjString *ostr;
+      std::vector<std::string> tokens;
       TString str;
       UInt_t ival;
 
-      tokens = line.Tokenize(", \t");
+      tokens = PStringUtils::Split(line.Data(), ", \t");
 
-      for (Int_t i=1; i<tokens->GetEntries(); i++) {
-        ostr = dynamic_cast<TObjString*>(tokens->At(i));
-        str = ostr->GetString();
+      for (Int_t i=1; i<static_cast<int>(tokens.size()); i++) {
+        str = tokens[i].c_str();
 
         if (str.IsDigit()) { // token might be a parameter number
           ival = str.Atoi();
@@ -1205,10 +1136,6 @@ Bool_t PFitter::CheckCommands()
             std::cerr  << std::endl << ">> Parameter " << ival << " is out of the Parameter Range [1," << fParams.size() << "]";
             std::cerr  << std::endl;
             fIsValid = false;
-            if (tokens) {
-              delete tokens;
-              tokens = nullptr;
-            }
             break;
           }
         } else { // token might be a parameter name
@@ -1226,19 +1153,11 @@ Bool_t PFitter::CheckCommands()
             std::cerr  << std::endl << ">> Parameter '" << str.Data() << "' is NOT present as a parameter name";
             std::cerr  << std::endl;
             fIsValid = false;
-            if (tokens) {
-              delete tokens;
-              tokens = nullptr;
-            }
             break;
           }
         }
       }
 
-      if (tokens) {
-        delete tokens;
-        tokens = nullptr;
-      }
 
       // everything looks fine, feed the command list
       cmd.first  = PMN_FIX;
@@ -1278,16 +1197,14 @@ Bool_t PFitter::CheckCommands()
       fCmdList.push_back(cmd);
     } else if (line.Contains("RELEASE", TString::kIgnoreCase)) {
       // check if the given set of parameters (number or names) is present
-      TObjArray *tokens = nullptr;
-      TObjString *ostr;
+      std::vector<std::string> tokens;
       TString str;
       UInt_t ival;
 
-      tokens = line.Tokenize(", \t");
+      tokens = PStringUtils::Split(line.Data(), ", \t");
 
-      for (Int_t i=1; i<tokens->GetEntries(); i++) {
-        ostr = dynamic_cast<TObjString*>(tokens->At(i));
-        str = ostr->GetString();
+      for (Int_t i=1; i<static_cast<int>(tokens.size()); i++) {
+        str = tokens[i].c_str();
 
         if (str.IsDigit()) { // token might be a parameter number
           ival = str.Atoi();
@@ -1298,10 +1215,6 @@ Bool_t PFitter::CheckCommands()
             std::cerr  << std::endl << ">> Parameter " << ival << " is out of the Parameter Range [1," << fParams.size() << "]";
             std::cerr  << std::endl;
             fIsValid = false;
-            if (tokens) {
-              delete tokens;
-              tokens = nullptr;
-            }
             break;
           }
         } else { // token might be a parameter name
@@ -1319,19 +1232,11 @@ Bool_t PFitter::CheckCommands()
             std::cerr  << std::endl << ">> Parameter '" << str.Data() << "' is NOT present as a parameter name";
             std::cerr  << std::endl;
             fIsValid = false;
-            if (tokens) {
-              delete tokens;
-              tokens = nullptr;
-            }
             break;
           }
         }
       }
 
-      if (tokens) {
-        delete tokens;
-        tokens = nullptr;
-      }
       cmd.first  = PMN_RELEASE;
       cmd.second = cmdLineNo;
       fCmdList.push_back(cmd);
@@ -1348,16 +1253,14 @@ Bool_t PFitter::CheckCommands()
       cmd.second = cmdLineNo;
       fCmdList.push_back(cmd);
       // filter out possible parameters for scan
-      TObjArray *tokens = nullptr;
-      TObjString *ostr;
+      std::vector<std::string> tokens;
       TString str;
       UInt_t ival;
 
-      tokens = line.Tokenize(", \t");
+      tokens = PStringUtils::Split(line.Data(), ", \t");
 
-      for (Int_t i=0; i<tokens->GetEntries(); i++) {
-        ostr = dynamic_cast<TObjString*>(tokens->At(i));
-        str = ostr->GetString();
+      for (Int_t i=0; i<static_cast<int>(tokens.size()); i++) {
+        str = tokens[i].c_str();
         if (i==1) { // get parameter number
           // check that token is a UInt_t
           if (!str.IsDigit()) {
@@ -1367,10 +1270,6 @@ Bool_t PFitter::CheckCommands()
             std::cerr  << std::endl << ">> command syntax for SCAN is: SCAN [parameter no [# of points [low high]]]";
             std::cerr  << std::endl;
             fIsValid = false;
-            if (tokens) {
-              delete tokens;
-              tokens = nullptr;
-            }
             break;
           }
           ival = str.Atoi();
@@ -1382,10 +1281,6 @@ Bool_t PFitter::CheckCommands()
             std::cerr  << std::endl << ">> command syntax for SCAN is: SCAN [parameter no [# of points [low high]]]";
             std::cerr  << std::endl;
             fIsValid = false;
-            if (tokens) {
-              delete tokens;
-              tokens = nullptr;
-            }
             break;
           }
           // keep parameter
@@ -1402,10 +1297,6 @@ Bool_t PFitter::CheckCommands()
             std::cerr  << std::endl << ">> command syntax for SCAN is: SCAN [parameter no [# of points [low high]]]";
             std::cerr  << std::endl;
             fIsValid = false;
-            if (tokens) {
-              delete tokens;
-              tokens = nullptr;
-            }
             break;
           }
           ival = str.Atoi();
@@ -1416,10 +1307,6 @@ Bool_t PFitter::CheckCommands()
             std::cerr  << std::endl << ">> command syntax for SCAN is: SCAN [parameter no [# of points [low high]]]";
             std::cerr  << std::endl;
             fIsValid = false;
-            if (tokens) {
-              delete tokens;
-              tokens = nullptr;
-            }
             break;
           }
           fScanNoPoints = ival;
@@ -1434,10 +1321,6 @@ Bool_t PFitter::CheckCommands()
             std::cerr  << std::endl << ">> command syntax for SCAN is: SCAN [parameter no [# of points [low high]]]";
             std::cerr  << std::endl;
             fIsValid = false;
-            if (tokens) {
-              delete tokens;
-              tokens = nullptr;
-            }
             break;
           }
           fScanLow = str.Atof();
@@ -1452,33 +1335,23 @@ Bool_t PFitter::CheckCommands()
             std::cerr  << std::endl << ">> command syntax for SCAN is: SCAN [parameter no [# of points [low high]]]";
             std::cerr  << std::endl;
             fIsValid = false;
-            if (tokens) {
-              delete tokens;
-              tokens = nullptr;
-            }
             break;
           }
           fScanHigh = str.Atof();
         }
       }
 
-      if (tokens) {
-        delete tokens;
-        tokens = nullptr;
-      }
     } else if (line.Contains("SIMPLEX", TString::kIgnoreCase)) {
       cmd.first  = PMN_SIMPLEX;
       cmd.second = cmdLineNo;
       fCmdList.push_back(cmd);
     } else if (line.Contains("STRATEGY", TString::kIgnoreCase)) {
-      TObjArray *tokens = nullptr;
-      TObjString *ostr;
+      std::vector<std::string> tokens;
       TString str;
 
-      tokens = line.Tokenize(" \t");
-      if (tokens->GetEntries() == 2) {
-        ostr = dynamic_cast<TObjString*>(tokens->At(1));
-        str = ostr->GetString();
+      tokens = PStringUtils::Split(line.Data(), " \t");
+      if (static_cast<int>(tokens.size()) == 2) {
+        str = tokens[1].c_str();
         if (str.CompareTo("0") == 0) { // low
           fStrategy = 0;
         } else if (str.CompareTo("1") == 0) { // default
@@ -1494,10 +1367,6 @@ Bool_t PFitter::CheckCommands()
         }
       }
 
-      if (tokens) {
-        delete tokens;
-        tokens = nullptr;
-      }
     } else if (line.Contains("USER_COVARIANCE", TString::kIgnoreCase)) {
       cmd.first  = PMN_USER_COVARIANCE;
       cmd.second = cmdLineNo;
@@ -1513,35 +1382,28 @@ Bool_t PFitter::CheckCommands()
       fCmdList.push_back(cmd);
 
       // check if the given sector arguments are valid time stamps, i.e. doubles and value < lgb time stamp
-      TObjArray *tokens = nullptr;
-      TObjString *ostr;
+      std::vector<std::string> tokens;
       TString str;
 
-      tokens = line.Tokenize(" ,\t");
+      tokens = PStringUtils::Split(line.Data(), " ,\t");
 
-      if (tokens->GetEntries() == 1) { // no sector time stamps given -> issue an error
+      if (static_cast<int>(tokens.size()) == 1) { // no sector time stamps given -> issue an error
         std::cerr << std::endl << ">> PFitter::CheckCommands(): **FATAL ERROR** in line " << it->fLineNo;
         std::cerr << std::endl << ">> " << line.Data();
         std::cerr << std::endl << ">> At least one sector time stamp is expected.";
         std::cerr << std::endl << ">> Will stop ...";
         std::cerr << std::endl;
-        // cleanup
-        if (tokens) {
-          delete tokens;
-          tokens = nullptr;
-        }
         fIsValid = false;
         fSectorFlag = false;
         break;
       }
 
       Double_t dval;
-      for (Int_t i=1; i<tokens->GetEntries(); i++) {
+      for (Int_t i=1; i<static_cast<int>(tokens.size()); i++) {
         // keep time range of sector
         PSectorChisq sec(fRunInfo->GetNoOfRuns());
         // get parse tokens
-        ostr = dynamic_cast<TObjString*>(tokens->At(i));
-        str = ostr->GetString();
+        str = tokens[i].c_str();
         if (str.IsFloat()) {
           dval = str.Atof();
           // check that the sector time stamp is smaller than all lgb time stamps
@@ -1552,11 +1414,6 @@ Bool_t PFitter::CheckCommands()
               std::cerr << std::endl << ">> The sector time stamp " << dval << " is > as the lgb time stamp (" << fOriginalFitRange[j].second << ") of run " << j << ".";
               std::cerr << std::endl << ">> Will stop ...";
               std::cerr << std::endl;
-              // cleanup
-              if (tokens) {
-                delete tokens;
-                tokens = nullptr;
-              }
               fIsValid = false;
               fSectorFlag = false;
               return fIsValid;
@@ -1571,21 +1428,12 @@ Bool_t PFitter::CheckCommands()
           std::cerr << std::endl << ">> The sector time stamp '" << str << "' is not a number.";
           std::cerr << std::endl << ">> Will stop ...";
           std::cerr << std::endl;
-          // cleanup
-          if (tokens) {
-            delete tokens;
-            tokens = nullptr;
-          }
           fIsValid = false;
           fSectorFlag = false;
           break;
         }
       }
 
-      if (tokens) {
-        delete tokens;
-        tokens = nullptr;
-      }
     } else { // unkown command
       std::cerr << std::endl << ">> PFitter::CheckCommands(): **FATAL ERROR** in line " << it->fLineNo << " an unkown command is found:";
       std::cerr << std::endl << ">> " << line.Data();
@@ -1729,27 +1577,24 @@ Bool_t PFitter::ExecuteFitRange(UInt_t lineNo)
     return true;
   }
 
-  TObjArray *tokens = nullptr;
-  TObjString *ostr;
+  std::vector<std::string> tokens;
   TString str;
 
-  tokens = fCmdLines[lineNo].fLine.Tokenize(", \t");
+  tokens = PStringUtils::Split(fCmdLines[lineNo].fLine.Data(), ", \t");
 
   PMsrRunList *runList = fRunInfo->GetMsrRunList();
 
   // execute command, no error checking needed since this has been already carried out in CheckCommands()
-  if (tokens->GetEntries() == 2) { // reset command
+  if (static_cast<int>(tokens.size()) == 2) { // reset command
     fRunListCollection->SetFitRange(fOriginalFitRange);
-  } else if (tokens->GetEntries() == 3) { // single fit range for all runs    
+  } else if (static_cast<int>(tokens.size()) == 3) { // single fit range for all runs    
     Double_t start = 0.0, end = 0.0;
     PDoublePair fitRange;
     PDoublePairVector fitRangeVector;
 
-    ostr = dynamic_cast<TObjString*>(tokens->At(1));
-    str = ostr->GetString();
+    str = tokens[1].c_str();
     start = str.Atof();
-    ostr = dynamic_cast<TObjString*>(tokens->At(2));
-    str = ostr->GetString();
+    str = tokens[2].c_str();
     end = str.Atof();
 
     fitRange.first  = start;
@@ -1763,11 +1608,9 @@ Bool_t PFitter::ExecuteFitRange(UInt_t lineNo)
     PDoublePairVector fitRangeVector;
 
     for (UInt_t i=0; i<runList->size(); i++) {
-      ostr = dynamic_cast<TObjString*>(tokens->At(2*i+1));
-      str = ostr->GetString();
+      str = tokens[2*i+1].c_str();
       start = str.Atof();
-      ostr = dynamic_cast<TObjString*>(tokens->At(2*i+2));
-      str = ostr->GetString();
+      str = tokens[2*i+2].c_str();
       end = str.Atof();
 
       fitRange.first  = start;
@@ -1795,15 +1638,13 @@ Bool_t PFitter::ExecuteFix(UInt_t lineNo)
 {
   std::cout << ">> PFitter::ExecuteFix(): " << fCmdLines[lineNo].fLine.Data() << std::endl;
 
-  TObjArray *tokens = nullptr;
-  TObjString *ostr;
+  std::vector<std::string> tokens;
   TString str;
 
-  tokens = fCmdLines[lineNo].fLine.Tokenize(", \t");
+  tokens = PStringUtils::Split(fCmdLines[lineNo].fLine.Data(), ", \t");
 
-  for (Int_t i=1; i<tokens->GetEntries(); i++) {
-    ostr = dynamic_cast<TObjString*>(tokens->At(i));
-    str = ostr->GetString();
+  for (Int_t i=1; i<static_cast<int>(tokens.size()); i++) {
+    str = tokens[i].c_str();
 
     if (str.IsDigit()) { // token is a parameter number
       fMnUserParams.Fix(static_cast<UInt_t>(str.Atoi())-1);
@@ -1812,11 +1653,6 @@ Bool_t PFitter::ExecuteFix(UInt_t lineNo)
     }
   }
 
-  // clean up
-  if (tokens) {
-    delete tokens;
-    tokens = nullptr;
-  }
 
   return true;
 }
@@ -2124,19 +1960,17 @@ Bool_t PFitter::ExecutePrintLevel(UInt_t lineNo)
 {
   std::cout << ">> PFitter::ExecutePrintLevel(): " << fCmdLines[lineNo].fLine.Data() << std::endl;
 
-  TObjArray *tokens = nullptr;
-  TObjString *ostr;
+  std::vector<std::string> tokens;
   TString str;
 
-  tokens = fCmdLines[lineNo].fLine.Tokenize(", \t");
+  tokens = PStringUtils::Split(fCmdLines[lineNo].fLine.Data(), ", \t");
 
-  if (tokens->GetEntries() < 2) {
+  if (static_cast<int>(tokens.size()) < 2) {
     std::cerr  << std::endl << "**ERROR** from PFitter::ExecutePrintLevel(): SYNTAX: PRINT_LEVEL <N>, where <N>=0-3" << std::endl << std::endl;
     return false;
   }
 
-  ostr = (TObjString*)tokens->At(1);
-  str = ostr->GetString();
+  str = tokens[1].c_str();
 
   Int_t ival;
   if (str.IsDigit()) {
@@ -2159,11 +1993,6 @@ Bool_t PFitter::ExecutePrintLevel(UInt_t lineNo)
   ROOT::Minuit2::MnPrint::SetLevel(fPrintLevel);
 #endif
 
-  // clean up
-  if (tokens) {
-    delete tokens;
-    tokens = nullptr;
-  }
 
   return true;
 }
@@ -2180,17 +2009,15 @@ Bool_t PFitter::ExecutePrintLevel(UInt_t lineNo)
  */
 Bool_t PFitter::ExecuteRelease(UInt_t lineNo)
 {
-  TObjArray *tokens = nullptr;
-  TObjString *ostr;
+  std::vector<std::string> tokens;
   TString str;
 
-  tokens = fCmdLines[lineNo].fLine.Tokenize(", \t");
+  tokens = PStringUtils::Split(fCmdLines[lineNo].fLine.Data(), ", \t");
 
   std::cout << ">> PFitter::ExecuteRelease(): " << fCmdLines[lineNo].fLine.Data() << std::endl;
 
-  for (Int_t i=1; i<tokens->GetEntries(); i++) {
-    ostr = dynamic_cast<TObjString*>(tokens->At(i));
-    str = ostr->GetString();
+  for (Int_t i=1; i<static_cast<int>(tokens.size()); i++) {
+    str = tokens[i].c_str();
 
     if (str.IsDigit()) { // token is a parameter number
       fMnUserParams.Release(static_cast<UInt_t>(str.Atoi())-1);
@@ -2203,11 +2030,6 @@ Bool_t PFitter::ExecuteRelease(UInt_t lineNo)
     }
   }
 
-  // clean up
-  if (tokens) {
-    delete tokens;
-    tokens = nullptr;
-  }
 
   return true;
 }